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High inhibitor concentrations in lignocellulose feedstock negatively affect the degradation rate of biodetoxification strains. This study designed two adaptive laboratory evolutions in solid substrate and liquid medium to boost the biodetoxification capacity of P. variotii to high titers of lignocellulose-derived inhibitors, resulting in two evolved strains AC70 and ZW70. The results showed that the evolutionary adaptation in liquid medium could better boost the acetic acid assimilation compared to that on solid substrate. Transcriptional analysis revealed that the evolved strains exhibited a significant upregulation of adh, acs, ach1, and ackA directly related to the initial steps of acetate and furan aldehydes metabolisms. ZW70 strain can effectively remove the high concentration inhibitors cocktail from the hydrolysates derived from pretreated wheat straw and furfural residues. The biodetoxified hydrolysates by ZW70 were successfully used for cellulose chiral L-lactic acid production with the titers of ∼110 g/L, which were over 20 % higher than that detoxified by parental strain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

For the last two decades, the aromatic aldehyde 5-hydroxymethyl-furfural (5-HMF) has been the subject of several investigations for its pharmacologic potential. In 2004, the Safo group reported that 5-HMF has potent antisickling activity by targeting and ameliorating the primary pathophysiology of hypoxia-induced sickling of erythrocytes (red blood cells [RBC]). Following the encouraging outcome of the preclinical and phase I/II clinical studies of 5-HMF for the treatment of sickle cell disease (SCD), there have been multiple studies suggesting 5-HMF has several other biological or pharmacologic activities, including anti-allergic, antioxidant, anti-hypoxic, anti-ischemic, cognitive improvement, anti-tyrosinase, anti-proliferation, cytoprotective, and anti-inflammatory activities. The wide range of its effects makes 5-HMF a potential candidate for treating a variety of diseases including cognitive disorders, gout, allergic disorders, anemia, hypoxia, cancers, ischemia, hemorrhagic shock, liver fibrosis, and oxidative injury. Several of these therapeutic claims are currently under investigation and, while promising, vary in terms of the strength of their evidence. This review presents the research regarding the therapeutic potential of 5-HMF in addition to its sources, physicochemical properties, safety, absorption, distribution, metabolism, and excretion (ADME) profiles., (© 2024 The Author(s). Medicinal Research Reviews published by Wiley Periodicals LLC.)

Bee products, including bee pollen (BP) and bee bread (BB) are natural sources that contain a diverse range of bioactive compounds. The objective of this study was to investigate the potential of BP and BB to enhance the functional properties of shortcrust pastry cookies. The impact on BP and BB on the colour parameters, polyphenolic compounds content, heat-induced compounds content (acrylamide, furfural, 5-hydroxymethylfurfural (HMF)), antioxidant properties, and inhibitory effects against advanced glycation end products (AGEs) formation and acetylcholinesterase (AChE) activity was examine by enriching cookies with 3 and 10% of BP or BB. The incorporation of BP or BB resulted in a notable darkening of the cookies. The spectroscopic and chromatographic analyses revealed that the cookies enriched with bee products exhibited an elevated content of phenolic compounds. The antioxidant activity (AA) of the enriched cookies exhibited an average increase of 2- to 3-fold in the ABTS test and 2-fold in the DPPH test. All cookies exhibited inhibitory potential against AGEs formation, witch inhibitory rates ranging from 10.64 to 46.22% in the BSA-GLU model and 1.75-19.33% in BSA-MGO model. The cookies enriched with 10% BP were characterised by to the highest level of AChE activity inhibition (13.72%). The incorporation of BB and BP resulted in elevated concentration of acrylamide, furfural, and HMF. Our findings suggest that bee products may serve as a valuable addition to food ingredients, significantly enhancing the functional properties of shortcrust pastry cookies. However, further investigation is necessary to address the increased level of heat-induced compounds., (© 2024. The Author(s).)

The process of preprocessing techniques such as acid and alkali pretreatment in lignocellulosic industry generates substantial solid residues and lignocellulosic pretreatment wastewater (LPW) containing glucose, xylose and toxic byproducts. In this study, furfural and vanillin were selected as model toxic byproducts. Kurthia huakuii as potential strain could tolerate to high concentrations of inhibitors. The results indicated that vanillin exhibited a higher inhibitory effect on K. huakuii (3.95 % inhibition rate at 1 g/L than furfural (0.45 %). However, 0.5 g/L vanillin promoted the bacterial growth (-2.35 % inhibition rate). Interestingly, the combination of furfural and vanillin exhibited antagonistic effects on bacterial growth (Q<0.85). Furfural and vanillin could be bio-transformed into less toxic molecules (furfuryl alcohol, furoic acid, vanillyl alcohol, and vanillic acid) by K. huakuii, and inhibitor degradation rate could be promoted by expression of antioxidant enzymes. This study provides important insights into how bacteria detoxify inhibitors in LPW, potentially enhancing resource utilization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. We declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Lignocellulosic material is a leading carbon source for economically viable biotechnological processes; however, compounds such furfural and acetic acid exhibit toxicity to yeasts. Nonetheless, research about the molecular mechanism of furfural and acetic acid toxicity is still scarce in yeasts like Scheffersomyces stipitis. Thus, this study aims to elucidate the impact of furfural and acetic acid on S. stipitis regarding bioenergetic and fermentation parameters. Here, we provide evidence that furfural and acetic acid induce a delay in cell growth and extend the lag phase. The mitochondrial membrane potential decreased in all treatments with no significant differences between inhibitors or concentrations. Interestingly, reactive oxygen species increased when the inhibitor concentrations were from 0.1 to 0.3 % (v/v). The glycolytic flux was not significantly (p > 0.05) altered by acetic acid, but furfural caused different effects. Ethanol production decreased significantly (4.32 g·L -1 in furfural and 5.06 g·L -1 in acetic acid) compared to the control (26.3 g·L -1 ). In contrast, biomass levels were not significantly different in most treatments compared to the control. This study enhances our understanding of the effects of furfural and acetic acid at the mitochondrial level in a pentose-fermenting yeast like S. stipitis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Furfural-tolerant and hydrogen-producing microbial consortia were enriched from soil, with hydrogen production of 259.84 mL/g-xylose under 1 g/L furfural stress. The consortia could degrade 2.5 g/L furfural within 24 h in the xylose system, more efficient than in the sugar-free system. Despite degradation of furfural to furfuryl alcohol, the release of reactive oxygen species and lactate dehydrogenase was also detected, suggesting that furfuryl alcohol is also a potential inhibitor of hydrogen production. The butyrate/acetate ratio was observed to decrease with increasing furfural concentration, leading to decreased hydrogen production. Furthermore, microbial community analysis suggested that dominated Clostridium butyricum was responsible for furfural degradation, while Clostridium beijerinckii reduction led to hydrogen production decrease. Overall, the enriched consortia in this study could efficiently degrade furfural and produce hydrogen, providing new insights into hydrogen-producing microbial consortia with furfural tolerance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Abundant renewable resource lignocellulosic biomass possesses tremendous potential for green biomanufacturing, while its efficient utilization by Yarrowia lipolytica, an attractive biochemical production host, is restricted since the presence of inhibitors furfural and acetic acid in lignocellulosic hydrolysate. Given deficient understanding of inherent interactions between inhibitors and cellular metabolism, sufficiently mining relevant genes is necessary. Herein, 14 novel gene targets were discovered using clustered regularly interspaced short palindromic repeats interference library in Y. lipolytica, achieving tolerance to 0.35 % (v/v) acetic acid (the highest concentration reported in Y. lipolytica), 4.8 mM furfural, or a combination of 2.4 mM furfural and 0.15 % (v/v) acetic acid. The tolerance mechanism might involve improvement of cell division and decrease of reactive oxygen species level. Transcriptional repression of effective gene targets still enabled tolerance when xylose was a carbon source. This work forms a robust foundation for improving microbial tolerance to lignocellulose-derived inhibitors and revealing underlying mechanism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Excessive accumulation of advanced glycation end products (AGEs) in the body is associated with diabetes and its complications. In this study, we aimed to explore the potential and mechanism of coffee leaf extract (CLE) in inhibiting the generation of AGEs and their precursors in an in vitro glycation model using bovine serum albumin and glucose (BSA-Glu) for the first time. High-performance liquid chromatography analysis revealed that CLE prepared with ultrasound pretreatment (CLE-U) contained higher levels of trigonelline, mangiferin, 3,5-dicaffeoylquinic acid, and γ-aminobutyric acid than CLE without ultrasound pretreatment (CLE-NU). The concentrations of these components, along with caffeine and rutin, were dramatically decreased when CLE-U or CLE-NU was incubated with BSA-Glu reaction mixture. Both CLE-U and CLE-NU exhibited a dose-dependent inhibition of fluorescent AGEs, carboxymethyllysine, fructosamine, 5-hydroxymethylfurfural, 3-deoxyglucosone, glyoxal, as well as protein oxidation products. Notably, CLE-U exhibited a higher inhibitory capacity compared to CLE-NU. CLE-U effectively quenched fluorescence intensity and increased the α-helix structure of the BSA-Glu complex. Molecular docking results suggested that the key bioactive compounds present in CLE-U interacted with the arginine residues of BSA, thereby preventing its glycation. Overall, this research sheds light on the possible application of CLE as a functional ingredient in combating diabetes by inhibiting the generation of AGEs., (© 2024 Institute of Food Technologists.)

Allergic inflammation is the foundation of multiple allergic disorders, such as allergic rhinitis and asthma. Mast cells are effector cells that initiate inflammatory response. 5-hydroxymethylfurfural (5-HMF), a furfural compound, is the heat-processed product of various fruit, foods, drinks, as well as some Chinese herbal medicines. 5-HMF was previously reported to inhibit mast cell activation. Our study aimed to explore the functions of 5-HMF in both phorbol 12-mystate 13-acetate (PMA) plus calcium ionophore (A23187)-induced allergic inflammation in human mast cell line HMC-1 and ovalbumin (OVA)-induced asthma mouse models. HMC-1 cells were pretreated with 5-HMF and then stimulated by PMA+A23187. The cytotoxicity of 5-HMF on HMC-1 cells was evaluated by MTT assay. Histamine content in cell supernatants was measured by the o-phthaldialdehyde spectrofluorometric procedure. Intracellular calcium was determined using the fluorescent dye Fura-2AM. The production and expression of pro-inflammatory cytokines were detected by ELISA and RT-qPCR. Caspase-1 colorimetric assay was employed to examine the enzymatic activity of caspase-1. Asthma mouse models were induced by OVA sensitization. The bronchoalveolar lavage fluid (BALF) and blood samples were collected for the detection of total and differential cell count as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT), OVA-immunoglobulin E (OVA-IgE), OVA-immunoglobulin G1 (OVA-IgG1), and pro-inflammatory cytokine levels. The left lung of mouse was dissected for histopathological examination by hematoxylin and eosin (H&E) staining. The protein expression of pro-caspase-1 and the phosphorylation of NF-κB and MAPK pathway-associated molecules were assessed by Western blotting. Our findings revealed that 5-HMF efficiently suppressed the PMA+A23187-induced enhancement in histamine production and intracellular calcium in HMC-1 cells. Pro-inflammatory cytokine production and expression in HMC-1 cells were elevated after PMA plus A23187 stimulation, which, however, were inhibited by pretreatment of 5-HMF. Additionally, 5-HMF suppressed the activity of caspase-1 and the phosphorylation of NF-κB and MAPK-associated molecules including p65 NF-κB, p38 MAPK, ERK, and JNK in HMC-1 cells. In vivo experiments demonstrated that 5-HMF treatment reduced the lung/body weight index and total and differential (macrophages, neutrophils, lymphocytes, and eosinophils) cell counts in BALF of asthmatic mice, but exerted no influence on serum AST and ALT levels. Besides, 5-HMF reduced serum OVA-IgE and OVA-IgG1 levels, mitigated lung inflammation, and inhibited the NF-κB and MAPK signaling pathways in asthma mouse models. 5-HMF mitigates allergic inflammation in asthma by inactivating caspase-1 and NF-κB and MAPK signaling pathways., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Air pollution consists of complex mixtures of chemicals with serious deleterious health effects from acute and chronic exposure. To help understand the mechanisms by which adverse effects occur, the present work examines the responses of cultured human epidermal keratinocytes to specific chemicals commonly found in woodsmoke. Our earlier findings with liquid smoke flavoring (aqueous extract of charred wood) revealed that such extracts stimulated the expression of genes associated with oxidative stress and proinflammatory response, activated the aryl hydrocarbon receptor, thereby inducing cytochrome P4501A1 activity, and induced cross-linked envelope formation, a lethal event ordinarily occurring during terminal differentiation. The present results showed that furfural produced transcriptional responses resembling those of liquid smoke, cyclohexanedione activated the aryl hydrocarbon receptor, and several chemicals induced envelope formation. Of these, syringol permeabilized the cells to the egress of lactate dehydrogenase at a concentration close to that yielding envelope formation, while furfural induced envelope formation without permeabilization detectable in this way. Furfural (but not syringol) stimulated the incorporation of amines into cell proteins in extracts in the absence of transglutaminase activity. Nevertheless, both chemicals substantially increased the amount of cellular protein incorporated into envelopes and greatly altered the envelope protein profile. Moreover, the proportion of keratin in the envelopes was dramatically increased. These findings are consistent with the chemically induced protein cross-linking in the cells. Elucidating mechanisms by which this phenomenon occurs may help understand how smoke chemicals interact with proteins to elicit cellular responses, interpret bioassays of complex pollutant mixtures, and suggest additional sensitive ways to monitor exposures.

Pretreatment of lignocellulosic biomass produces growth inhibitory substances such as furfural which is toxic to microorganisms. Acinetobacter baylyi ADP1 cannot use furfural as a carbon source, instead it biotransforms this compound into difurfuryl ether using the reduced nicotinamide adenine dinucleotide (NADH)-dependent dehydrogenases AreB and FrmA during aerobic acetate catabolism. However, NADH consumption for furfural biotransformation compromises aerobic growth of A. baylyi ADP1. Depending on the growth phase, several genes related to acetate catabolism and oxidative phosphorylation changed their expression indicating that central metabolic pathways were affected by the presence of furfural. During the exponential growth phase, reactions involved in the formation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) (icd gene) and NADH (sfcA gene) were preferred when furfural was present. Therefore a higher NADH and NADPH production might support furfural biotransformation and biomass production, respectively. In contrast, in the stationary growth phase genes of the glyoxylate shunt were overexpressed probably to save carbon compounds for biomass formation, and only NADH regeneration was appreciated. Finally, disruption of the frmA or areB gene in A. baylyi ADP1 led to a decrease in growth adaptation and in the capacity to biotransform furfural. The characterization of this physiological behavior clarifies the impact of furfural in Acinetobacter metabolism., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

The knowledge of the relationship between the chemical structure of food components with their mechanisms of action is crucial for the understanding of diet health benefits. This review relates the chemical variability present in coffee beverages with the mechanisms involved in key physiological events, supporting coffee as a polyvalent functional food. Coffee intake has been related with several health-promoting properties such as neuroprotective (caffeine, chlorogenic acids and melanoidins), anti-inflammatory (caffeine, chlorogenic acids, melanoidins, diterpenes), microbiota modulation (polysaccharides, melanoidins, chlorogenic acids), immunostimulatory (polysaccharides), antidiabetic (trigonelline, chlorogenic acids), antihypertensive (chlorogenic acids) and hypocholesterolemic (polysaccharides, chlorogenic acids, lipids). Nevertheless, caffeine and diterpenes are coffee components with ambivalent effects on health. Additionally, a large range of potentially harmful compounds, including acrylamide, hydroxymethylfurfural, furan, and advanced glycation end products, are formed during the roasting of coffee and are present in the beverages. However, coffee beverages are part of the daily human dietary healthy habits, configuring a coffee paradox.

Lignocellulosic biomass represents a carbon neutral cheap and versatile source of carbon which can be converted to biofuels. A pretreatment step is frequently used to make the lignocellulosic carbon bioavailable for microbial metabolism. Dilute acid pretreatment at high temperature and pressure is commonly utilized to efficiently solubilize the pentose fraction by hydrolyzing the hemicellulose fibers and the process results in formation of furans-furfural and 5-hydroxymethyl furfural-and other inhibitors which are detrimental to metabolism. The presence of inhibitors in the medium reduce productivity of microbial biocatalysts and result in increased production costs. Furfural is the key furan inhibitor which acts synergistically along with other inhibitors present in the hydrolysate. In this review, the mode of furfural toxicity on microbial metabolism and metabolic strategies to increase tolerance is discussed. Shared cellular targets between furfural and acetic acid are compared followed by discussing further strategies to engineer tolerance. Finally, the possibility to use furfural as a model inhibitor of dilute acid pretreated lignocellulosic hydrolysate is discussed. The furfural tolerant strains will harbor an efficient lignocellulosic carbon to pyruvate conversion mechanism in presence of stressors in the medium. The pyruvate can be channeled to any metabolite of interest by appropriate modulation of downstream pathway of interest. The aim of this review is to emphasize the use of hydrolysate as a carbon source for bioproduction of biofuels and other compounds of industrial importance., (© 2023. The Author(s).)

The yeast Saccharomyces cerevisiae able to tolerate lignocellulose-derived inhibitors like furfural. Yeast strain performance tolerance has been measured by the length of the lag phase for cell growth in response to the furfural inhibitor challenge. The aims of this work were to obtain RDS1 yeast tolerant strain against furfural through overexpression using a method of in vivo homologous recombination. Here, we report that the overexpressing RDS1 recovered more rapidly and displayed a lag phase at about 12 h than its parental strain. Overexpressing RDS1 strain encodes a novel aldehyde reductase with catalytic function for reduction of furfural with NAD(P)H as the co-factor. It displayed the highest specific activity (24.8 U/mg) for furfural reduction using NADH as a cofactor. Fluorescence microscopy revealed improved accumulation of reactive oxygen species resistance to the damaging effects of inhibitor in contrast to the parental. Comparative transcriptomics revealed key genes potentially associated with stress responses to the furfural inhibitor, including specific and multiple functions involving defensive reduction-oxidation reaction process and cell wall response. A significant change in expression level of log2 (fold change >1) was displayed for RDS1 gene in the recombinant strain, which demonstrated that the introduction of RDS1 overexpression promoted the expression level. Such signature expressions differentiated tolerance phenotypes of RDS1 from the innate stress response of its parental strain. Overexpression of the RDS1 gene involving diversified functional categories is accountable for stress tolerance in yeast S. cerevisiae to survive and adapt the furfural during the lag phase., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Lignocellulose's hydrolysate, a significant renewable source, contains xylose and furfural, making it challenging for industrial production of oleaginous yeast. On xylose fermentation with furfural treatment, OE::DN7263 and OE::DN7661 increased lipid yield and furfural tolerance versus WT, while, which of OE::CreA were decreased owing to CreA regulating DN7263 and DN7661 negatively. OE::CreA generated reactive oxygen species (ROS) causing oxidative damage. OE::DN7263, OE::DN7661, and ΔCreA reduced furfural via NADH; while ΔCreA produced less ROS and OE::DN7263, and OE::DN7661 scavenged ROS quickly, minimizing oxidative damage. Overall, CreA knockout increased DN7263 and DN7661 expression to facilitate xylose assimilation, enhancing NADH generation and ROS clearance. Finally, with mixed sugar fermentation, ΔCreA and OE::DN7263's biomass and lipid yield rose without furfural addition, while that of ΔCreA remained higher than WT after furfural treatment. These findings revealed how oleaginous yeast zwy-2-3 resisted furfural stress and indicated ΔCreA and OE::DN7263 might develop into robust industrial chassis strains., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In this study were synthesized non-Michael acceptor cyclopentenones (CP) from biomass derivative furfural as anticancer agents. Cyclic enones, both from natural sources and synthetic analogues, have been described as cytotoxic agents. Most of these agents were unsuccessful in becoming valuable therapeutic agents due to toxicity problems derived from unselective critical biomacromolecule alkylation. This may be caused by Michael addition to the enone system. Ab initio studies revealed that 2,4-substituted CPs are less prone to Michael additions, and as such were tested three families of those derivatives. We prepare the new CPs from furfural through a tandem furan ring opening/Nazarov electrocyclization and further functionalization. Experimentally the 2,4-substituted CPs exhibited no reactivity towards sulphur nucleophiles, while maintaining cytotoxicity against HT-29, MCF-7, NCI-H460, HCT-116 and MDA-MB 231 cells lines. Moreover, the selected CP are non-toxic against healthy HEK 293T cell lines and present proper calculated drug-like properties., (© 2023 The Authors. ChemMedChem published by Wiley-VCH GmbH.)

Lignocellulosic biomass is still considered a feasible source of bioethanol production. Saccharomyces cerevisiae can adapt to detoxify lignocellulose-derived inhibitors, including furfural. Tolerance of strain performance has been measured by the extent of the lag phase for cell proliferation following the furfural inhibitor challenge. The purpose of this work was to obtain a tolerant yeast strain against furfural through overexpression of YPR015C using the in vivo homologous recombination method. The physiological observation of the overexpressing yeast strain showed that it was more resistant to furfural than its parental strain. Fluorescence microscopy revealed improved enzyme reductase activity and accumulation of oxygen reactive species due to the harmful effects of furfural inhibitor in contrast to its parental strain. Comparative transcriptomic analysis revealed 79 genes potentially involved in amino acid biosynthesis, oxidative stress, cell wall response, heat shock protein, and mitochondrial-associated protein for the YPR015C overexpressing strain associated with stress responses to furfural at the late stage of lag phase growth. Both up- and down-regulated genes involved in diversified functional categories were accountable for tolerance in yeast to survive and adapt to the furfural stress in a time course study during the lag phase growth. This study enlarges our perceptions comprehensively about the physiological and molecular mechanisms implicated in the YPR015C overexpressing strain's tolerance under furfural stress. Construction illustration of the recombinant plasmid. a) pUG6-TEF1p-YPR015C, b) integration diagram of the recombinant plasmid pUG6-TEF1p-YPR into the chromosomal DNA of Saccharomyces cerevisiae ., (© 2023 Getachew Tafere Abrha et al., published by Sciendo.)

Modern agriculture has many environmental consequences, such as soil contamination, accumulation of toxic compounds in the environment or risk of adverse effects on nontarget organisms and for these reasons, scientists are seeking a more environmentally friendly alternative to synthetic insecticides. This study investigated the effects of four plant secondary metabolites classified as volatile organic compounds (VOCs), which have potential as bioinsecticides, (E)-2-decenal, furfural, 2-undecanone and (E,E)-2-4-decadienal, in concentrations 10 -5 and 10 -7 M, on female reproductive processes and larval hatchability of the Tenebrio molitor beetle. Our study indicates proper development of ovaries after application of compounds however the volume of terminal oocytes was significantly reduced, with the strongest effect of (E)- 2-decenal which reduced the volume approximately three times. The relative vitellogenin expression level was reduced, with the strongest effect observed after application of furfural, (E,E)- 2-4-decadienal and (E)- 2-decenal in concentration 10 -7 M, at the same time patency index was significantly reduced up to 2-times after application of furfural at 10 -7 M. What is more important morphological changes translated into physiological ones. The number of laid eggs was affected, with the strongest inhibition after application of furfural (∼43% reduction), (E,E)- 2-4-decadienal (∼33%) and (E)- 2-decenal at concentration 10 -7 M (∼33%). Moreover, we observed up to 13% (in case of 2-undecanone) decrease in larval hatchability. Tested compounds exhibited a repellent effect and caused 60% reduction of insect survivability after (E)- 2-decenal at concentration 10 -5 M. Altogether, VOCs seems like potential bioactive compounds in plant protection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

For 2G ethanol production, pentose fermentation and yeast tolerance to lignocellulosic hydrolyzate components are essential to improve biorefinery yields. Generally, physicochemical pre-treatment methodologies are used to facilitate access to cellulose and hemicellulose in plant material, which consequently can generate microbial growth inhibitory compounds, such as furans, weak acids, and phenolic compounds. Because of the unsatisfactory yield of wild-type Saccharomyces cerevisiae during pentose fermentation, the search for xylose-fermenting yeasts tolerant to microbial growth inhibitors has gained attention. In this study, we investigated the ability of the yeasts Pichia guilliermondii G1.2 and Candida oleophila G10.1 to produce ethanol from xylose and tolerate the inhibitors furfural, 5-hydroxymethylfurfural (HMF), acetic acid, formic acid, ferulic acid, and vanillin. We demonstrated that both yeasts were able to grow and consume xylose in the presence of all single inhibitors, with greater growth limitation in media containing furfural, acetic acid, and vanillin. In saline medium containing a mixture of these inhibitors (2.5-3.5 mM furfural and HMF, 1 mM ferulic acid, 1-1.5 mM vanillin, 10-13 mM acetic acid, and 5-7 mM formic acid), both yeasts were able to produce ethanol from xylose, similar to that detected in the control medium (without inhibitors). In future studies, the proteins involved in the transport of pentose and tolerance to these inhibitors need to be investigated., (© 2023. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Ethanol production at high temperatures using lignocellulosic biomass as feedstock requires a highly efficient thermo and lignocellulosic inhibitor-tolerant ethanologenic yeast. In this study, sixty-three yeast isolates were obtained from tropical acidic fruits using a selective acidified medium containing 80 mM glacial acetic acid. Twenty-nine of the yeast isolates exhibited significant thermo and acetic acid-tolerant fermentative abilities. All these isolates were classified into three major yeast species, namely Saccharomycodes ludwigii, Pichia kudriavzevii, and P. manshurica, based on molecular identification. Saccharomycodes ludwigii APRE2 displayed an ability to grow at high temperatures of up to 43 °C and exhibited significant multistress tolerance toward acetic acid, furfural, 5-hydroxymethyl furfural (5-HMF), and ethanol among the isolated yeast species. It can produce a maximum ethanol concentration of 63.07 g/L and productivity of 1.31 g/L.h in yeast extract malt extract (YM) medium containing 160 g/L glucose and supplemented with 80 mM acetic acid and 15 mM furfural as a cocktail inhibitor. When an acid-pretreated pineapple waste hydrolysate (PWH) containing approximately 106 g/L total sugars, 131 mM acetic acid, and 3.95 mM furfural was used as a feedstock, 38.02 g/L and 1.58 g/L.h of ethanol concentration and productivity, respectively, were achieved. Based on the results of the current study, the new thermo and acetic acid-tolerant yeast S. ludwigii APRE2 exhibited excellent potential for second-generation bioethanol production at high temperatures., (© 2022. The Author(s).)

Direct reutilization of condensate can inhibit ethanol fermentation, 2-phenylethyl alcohol and furfural existed in the condensate are considered to be inhibitors. To achieve the reutilization of the condensate, the ozonation combined with ion-exchange method was used. The results showed that the elimination rates of 2-phenylethyl alcohol and furfural reached 98.0% and 100.0%, respectively after ozonation, while the concentrations of acetic acid, propionic acid, butyric acid and valeric acid increased by 14.9%, 7.7%, 35.3% and 25.5%, respectively. The fermentation results showed that the inhibition of the condensate after ozonation was alleviated but was not completely eliminated. When the effluent volume treated by the ion-exchange method reached 80 BV, the concentrations of acetic acid, propionic acid, butyric acid and valeric acid decreased by 25.8%, 8.6%, 6.5% and 34.4%, respectively. The fermentation results showed that the inhibition of the condensate was completely eliminated after ozonation combined with ion-exchange treatment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Second generation (2G) ethanol is produced using lignocellulosic biomass. However, the pre-treatment processes generate a variety of molecules (furanic compounds, phenolic compounds, and organic acids) that act as inhibitors of microbial metabolism, and thus, reduce the efficiency of the fermentation step in this process. In this context, the present study aimed to investigate the effect of furanic compounds on the physiology of lactic acid bacteria (LAB) strains that are potential contaminants in ethanol production., Methodology: Homofermentative and heterofermentative strains of laboratory LAB, and isolated from first generation ethanol fermentation, were used. LAB strains were challenged to grow in the presence of furfural and 5-hydroxymethyl furfural (HMF)., Results: We determined that the effect of HMF and furfural on the growth rate of LAB is dependent on the metabolic type, and the growth kinetics in the presence of these compounds is enhanced for heterofermentative LAB, whereas they are inhibitory to homofermentative LAB. Sugar consumption and product formation were also enhanced in the presence of furanic compounds for heterofermentative LAB, who displayed effective depletion kinetics when compared to the homofermentative LAB., Conclusion: Homo- and heterofermentative LAB are affected differently by furanic compounds, in a way that the latter type is more resistant to the toxic effects of these inhibitors. This knowledge is important to understand the potential effects of bacterial contamination in 2G bioprocesses., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and biocompatible plastic that has the potential to replace petroleum-based plastics. Lignocellulosic biomass is a promising feedstock for industrial fermentation to produce bioproducts such as polyhydroxybutyrate (PHB). However, the pretreatment processes of lignocellulosic biomass lead to the generation of toxic byproducts, such as furfural, 5-HMF, vanillin, and acetate, which affect microbial growth and productivity. In this study, to reduce furfural toxicity during PHB production from lignocellulosic hydrolysates, we genetically engineered Cupriavidus necator NCIMB 11599, by inserting the nicotine amide salvage pathway genes pncB and nadE to increase the NAD(P)H pool. We found that the expression of pncB was the most effective in improving tolerance to inhibitors, cell growth, PHB production and sugar consumption rate. In addition, the engineered strain harboring pncB showed higher PHB production using lignocellulosic hydrolysates than the wild-type strain. Therefore, the application of NAD salvage pathway genes improves the tolerance of Cupriavidus necator to lignocellulosic-derived inhibitors and should be used to optimize PHB production., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The presence of furfural in the hydrolysates obtained from lignocellulosic biomass sources represents an enormous challenge during their fermentation because furfural is a toxic compound for different microorganisms. Rhodosporidium toruloides-1588 can grow and accumulate lipids using wood hydrolysate as a substrate containing up to 1 g/L of furfural. In this study, the capacity of R. toruloides-1588 to grow and accumulate lipids using furfural without glucose in the media has been observed. R. toruloides-1588 degraded up to 3 g/L of furfural into furfuryl alcohol (1.8 g/L) and 2-furoic acid (0.9 g/L). Furthermore, R. toruloides-1588 accumulated 52% and 30% of its dry weight into lipids using YM media and YM media without glucose, respectively. Fatty acids such as palmitic, stearic and oleic were the most abundant. Finally, R. toruloides-1588 could potentially utilize furfural as a carbon source., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The microbial conversion of pentoses to ethanol is one of the major drawbacks that limits the complete use of lignocellulosic sugars. In this study, we compared the yeast species Spathaspora arborariae, Spathaspora passalidarum, and Sheffersomyces stipitis regarding their potential use for xylose fermentation. Herein, we evaluated the effects of xylose concentration, presence of glucose, and temperature on ethanol production. The inhibitory effects of furfural, hydroxymethylfurfural (HMF), acetic acid, and ethanol were also determined. The highest ethanol yield (0.44 g/g) and productivity (1.02 g/L.h) were obtained using Sp. passalidarum grown in 100 g/L xylose at 32 °C. The rate of xylose consumption was reduced in the presence of glucose for the species tested. Hydroxymethylfurfural did not inhibit the growth of yeasts, whereas furfural extended their lag phase. Acetic acid inhibited the growth and fermentation of all yeasts. Furthermore, we showed that these xylose-fermenting yeasts do not produce ethanol concentrations greater than 4% (v/v), probably due to the inhibitory effects of ethanol on yeast physiology. Our data confirm that among the studied yeasts, Sp. passalidarum is the most promising for xylose fermentation, and the low tolerance to ethanol is an important aspect to be improved to increase its performance for second-generation (2G) ethanol production. Our molecular data showed that this yeast failed to induce the expression of some classical genes involved in ethanol tolerance. These findings suggest that Sp. passalidarum may have not activated a proper response to the stress, impacting its ability to overcome the negative effects of ethanol on the cells., (© 2022. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

While lignocellulose is a promising source of renewable sugars for microbial fermentations, the presence of inhibitory compounds in typical lignocellulosic feedstocks, such as furfural, has hindered their utilisation. In Escherichia coli, a major route of furfural toxicity is the depletion of NADPH pools due to its use as a substrate by the YqhD enzyme that reduces furfural to its less toxic alcohol form. Here, we examine the potential of exploiting benzyl alcohol dehydrogenases as an alternative means to provide this same catalytic function but using the more abundant reductant NADH, as a strategy to increase the capacity for furfural removal. We determine the biochemical properties of three of these enzymes, from Pseudomonas putida, Acinetobacter calcoaceticus, and Burkholderia ambifaria, which all demonstrate furfural reductase activity. Furthermore, we show that the P. putida and B. ambifaria enzymes are able to provide substantial increases in furfural tolerance in vivo, by allowing more rapid conversion to furfuryl alcohol and resumption of growth. The study demonstrates that methods to seek alternative cofactor dependent enzymes can improve the intrinsic robustness of microbial chassis to feedstock inhibitors., (© 2022 The Author(s).)

Cellulose is one of the main raw materials for production of green ethanol, but the presence of the growth inhibitor furfural in non-detoxified lignocellulosic hydrolysates often seriously affects their utilization. In a previous study, we obtained strains of Candida glycerinogenes that were tolerant to furfural, but at concentrations above 2.5 g L -1 there was a significant increase in the growth lag phase. In this work, transcription factor genes (SEF1, STB5, CAS5, and ETP1) associated with furfural tolerance were identified and employed to obtain modified strains permitting ethanol fermentation of concentrated and non-detoxified cellulose hydrolysates containing more than 2.5 g L -1 furfural. Tolerance to furfural could be increased to 4.5 g L -1 by overexpression of either STB5 or ETP1, which have different regulation patterns. Moreover, in non-detoxified and concentrated cellulose hydrolysate, overexpression of ETP1 significantly shortened the growth lag phase and ethanol fermentation time was reduced by 17-20%. In batch fermentations fed with concentrated non-detoxified lignocellulose hydrolysate, ethanol productivity and maximum ethanol concentration reached 2.4 g L -1 h -1 and 72.5 g L -1 , increases of 26.1% and 6.6%, respectively. The results provided a route for the economic use of lignocellulose for chemical production., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Yarrowia lipolytica , the non-conventional yeast capable of high lipogenesis, is a microbial chassis for producing lipid-based biofuels and chemicals from renewable resources such as lignocellulosic biomass. However, the low tolerance of Y. lipolytica against furfural, a major inhibitory furan aldehyde derived from the pretreatment processes of lignocellulosic biomass, has restricted the efficient conversion of lignocellulosic hydrolysates. In this study, the furfural tolerance of Y. lipolytica has been improved by supporting its endogenous detoxification mechanism. Specifically, the endogenous genes encoding the aldehyde dehydrogenase family proteins were overexpressed in Y. lipolytica to support the conversion of furfural to furoic acid. Among them, YALI0E15400p (FALDH2) has shown the highest conversion rate of furfural to furoic acid and resulted in two-fold increased cell growth and lipid production in the presence of 0.4 g/L of furfural. To our knowledge, this is the first report to identify the native furfural detoxification mechanism and increase furfural resistance through rational engineering in Y. lipolytica . Overall, these results will improve the potential of Y. lipolytica to produce lipids and other value-added chemicals from a carbon-neutral feedstock of lignocellulosic biomass.

Furfural acetone (FAc) is a promising alternative to currently available nematicides, and it exhibits equivalent control efficiency on root-knot nematodes with avermectin in fields. However, its effect on the reproduction of root-knot nematode is poorly understood. In this study, the natural metabolite FAc was found to exhibit reproductive toxicity on Meloidogyne incognita and Caenorhabditis elegans . The number of germ cells of C. elegans was observed to decrease after exposure to FAc, with a reduction of 59.9% at a dose of 200 mg/L. FAc in various concentrations induced the germ-cell apoptosis of C. elegans , with an increase over six-fold in the number of apoptotic germ cells at 200 mg/L. These findings suggested that FAc decreased the brood size of nematode by inducing germ-cell apoptosis. Moreover, FAc-induced germ-cell apoptosis was suppressed by the mutation of gene hus-1 , clk-2 , cep-1 , egl-1 , ced-3 , ced-4 , or ced-9 . The expression of genes spo-11 , cep-1 , and egl-1 in C. elegans was increased significantly after FAc treatment. Taken together, these results indicate that nematode exposure to FAc might inflict DNA damage through protein SPO-11, activate CEP-1 and EGL-1, and induce the core apoptosis pathway to cause germ-cell apoptosis, resulting in decreased brood size of C. elegans .

Furfural is a common furan inhibitor formed due to dehydration of pentose sugars, like xylose, and acts as an inhibitor of microbial metabolism. Overexpression of NADH-specific FucO and deletion of NADPH-specific YqhD had been a successful strategy in the past in conferring tolerance against furfural in Escherichia coli, which highlights the importance of oxidoreductases in conferring tolerance against furfural. In a screen consisting of various oxidoreductases, dehydrogenases, and reductases, we identified the yghA gene as an overexpression target to confer tolerance against furfural. YghA preferably used NADH as a cofactor and had an apparent K m value of 0.03 mM against furfural. In the presence of 1 g liter -1 furfural and 10% xylose (wt/vol), yghA overexpression in an ethanologenic E. coli strain SSK42 resulted in an ethanol efficiency of ∼97%, with a 5.3-fold increase in ethanol titers compared to the control. YghA also exhibited activity against the less toxic inhibitor 5-hydroxymethyl furfural, which is formed due to dehydration of hexose sugars, and thus is a formidable target for overexpression in ethanologenic strain for fermentation of sugars in biomass hydrolysate. IMPORTANCE Lignocellulosic biomass represents an inexhaustible source of carbon for second-generation biofuels. Thermo-acidic pretreatment of biomass is performed to loosen the lignocellulosic fibers and make the carbon bioavailable for microbial metabolism. The pretreatment process also results in the formation of inhibitors that inhibit microbial metabolism and increase production costs. Furfural is a potent furan inhibitor that increases the toxicity of other inhibitors present in the hydrolysate. Thus, it is desirable to engineer furfural tolerance in E. coli for efficient fermentation of hydrolysate sugars.

5-Hydroxymethylfurfural (5-HMF) is known to increase hemoglobin oxygen affinity (Hb-O 2 affinity) and to induce a left shift of the oxygen dissociation curve (ODC). It is under investigation as a therapeutic agent in sickle cell anemia and in conditions where pulmonary oxygen uptake is deteriorated or limited (e.g., various clinical conditions or altitude exposure). The combination of 5-HMF and α-ketoglutaric acid (αKG) is commercially available as a nutritional supplement. To further elucidate dose effects, ODCs were measured in vitro in venous whole blood samples of 20 healthy volunteers (10 female and 10 male) after the addition of three different doses of 5-HMF, αKG and the combination of both. Linear regression analysis revealed a strong dose-dependent increase in Hb-O 2 affinity for 5-HMF (R 2 = 0.887; p < 0.001) and the commercially available combination with αKG (R 2 = 0.882; p < 0.001). αKG alone increased Hb-O 2 affinity as well but to a lower extent. Both the combination (5-HMF + αKG) and 5-HMF alone exerted different P50 and Hill coefficient responses overall and between sexes, with more pronounced effects in females. With increasing Hb-O 2 affinity, the sigmoidal shape of the ODC was better preserved by the combination of 5-HMF and αKG than by 5-HMF alone. Concerning the therapeutic effects of 5-HMF, this study emphasizes the importance of adequate dosing in various physiological and clinical conditions, where a left-shifted ODC might be beneficial. By preserving the sigmoidal shape of the ODC, the combination of 5-HMF and αKG at low (both sexes) and medium (males only) doses might be able to better maintain efficient oxygen transport, particularly by mitigating potentially deteriorated oxygen unloading in the tissue. However, expanding knowledge on the interaction between 5-HMF and Hb-O 2 affinity in vitro necessitates further investigations in vivo to additionally assess pharmacokinetic mechanisms.

Lignocellulosic hydrolysates will also contain compounds that inhibit microbial metabolism, such as organic acids, furaldehydes, and phenolic compounds. Understanding the response of yeasts toward such inhibitors is important to the development of different bioprocesses. In this work, the growth capacity of 7 industrial Saccharomyces cerevisiae and 7 non-Saccharomyces yeasts was compared in the presence of 3 different concentrations of furaldehydes (furfural and 5-hydroxymetil-furfural), organic acids (acetic and formic acids), and phenolic compounds (vanillin, syringaldehyde, ferulic, and coumaric acids). Then, Candida tropicalis JA2, Meyerozyma caribbica JA9, Wickerhamomyces anomalus 740, S. cerevisiae JP1, B1.1, and G06 were selected for fermentation in presence of acetic acid, HMF, and vanillin because they proved to be most tolerant to the tested compounds, while Spathaspora sp. JA1 because its xylose consumption rate. The results obtained showed a dose-dependent response of the yeasts toward the eight different inhibitors. Among the compared yeasts, S. cerevisiae strains presented higher tolerance than non-Saccharomyces, 3 of them with the highest tolerance among all. Regarding the non-Saccharomyces yeasts, C. tropicalis JA2 and W. anomalus 740 appeared as the most tolerant, whereas Spathaspora strains appeared very sensitive to the different compounds.

Objectives: To determine furfural biotransformation capabilities of Acinetobacter baylyi ADP1 and Acinetobacter schindleri ACE., Results: Acinetobacter baylyi ADP1 and A. schindleri ACE could not use furfural as sole carbon source but when acetate was used as substrate, ADP1 and ACE biotransformed 1 g furfural/l in 5 and 9 h, respectively. In both cases, the product of this biotransformation was difurfuryl-ether as shown by FT-IR and 1 H and 13 C NMR spectroscopy. The presence of furfural decreased the specific growth rate in acetate by 27% in ADP1 and 53% in ACE. For both strains, the MIC of furfural was 1.25 g/l. Nonetheless, ADP1 biotransformed 2 g furfural/l at a rate of 1 g/l/h in the stationary phase of growth. A transcriptional analysis of possible dehydrogenases involved in this biotransformation, identified that the areB and frmA genes were highly overexpressed after the exposure of ADP1 to furfural. The products of these genes are a benzyl-alcohol dehydrogenase and an alcohol dehydrogenase., Conclusions: Acinetobacter baylyi ADP1 is a candidate for the biological detoxification of furfural, a fermentation inhibitor present in lignocellulosic hydrolysates, with the possible direct involvement of the AreB and FrmA enzymes in the process.

Acetic acid and furfural are the two prevalent inhibitors coexisting with glucose and xylose in lignocellulosic hydrolysate. The transcriptional regulations of Saccharomyces cerevisiae in response to acetic acid (Aa), furfural (Fur), and the mixture of acetic acid and furfural (Aa&#95;Fur) were revealed during mixed glucose and xylose fermentation. Carbohydrate metabolism pathways were significantly enriched in response to Aa, while pathways of xenobiotic biodegradation and metabolism were significantly enriched in response to Fur. In addition to these pathways, other pathways were activated in response to Aa&#95;Fur, i.e., cofactor and vitamin metabolism and lipid metabolism. Overexpression of Haa1p or Tye7p improved xylose consumption rates by nearly 50%, while the ethanol yield was enhanced by nearly 8% under acetic acid and furfural stress conditions. Co-overexpression of Haa1p and Tye7p resulted in a 59% increase in xylose consumption rate and a 12% increase in ethanol yield, revealing the beneficial effects of Haa1p and Tye7p on improving the tolerance of yeast to mixed acetic acid and furfural. IMPORTANCE Inhibitor tolerance is essential for S. cerevisiae when fermenting lignocellulosic hydrolysate with various inhibitors, including weak acids, furans, and phenols. The details regarding how xylose-fermenting S. cerevisiae strains respond to multiple inhibitors during fermenting mixed glucose and xylose are still unknown. This study revealed the transcriptional regulation mechanism of an industrial xylose-fermenting S. cerevisiae strain in response to acetic acid and furfural. The transcription factor Haa1p was found to be involved in both acetic acid and furfural tolerance. In addition to Haa1p, four other transcription factors, Hap4p, Yox1p, Tye7p, and Mga1p, were identified as able to improve the resistance of yeast to these two inhibitors. This study underscores the feasibility of uncovering effective transcription factors for constructing robust strains for lignocellulosic bioethanol production., (Copyright © 2021 American Society for Microbiology.)

Gaining an in-depth understanding of the response of Saccharomyces cerevisiae to the different inhibitors generated during the pretreatment of lignocellulosic material is driving the development of new strains with higher inhibitor tolerances. The objective of this study is to assess, using flow cytometry, how three common inhibitors (vanillin, furfural, and acetic acid) affect the membrane potential, the membrane permeability and the concentration of reactive oxygen species (ROS) during the different fermentations. The membrane potential decreased during the detoxification phase and reflected on the different mechanisms of the toxicity of the inhibitors. While vanillin and furfural caused a metabolic inhibition and a gradual depolarization, acetic acid toxicity was related to fast acidification of the cytosol, causing an immediate depolarization. In the absence of acetic acid, ethanol increased membrane permeability, indicating a possible acquired tolerance to ethanol due to an adaptive response to acetic acid. The intracellular ROS concentration also increased in the presence of the inhibitors, indicating oxidative stress. Measuring these features with flow cytometry allows a real-time assessment of the stress of a cell culture, which can be used in the development of new yeast strains and to design new propagation strategies to pre-adapt the cell cultures to the inhibitors.

Background: Lignocellulosic material is a suitable renewable carbon and energy source for microbial cell factories, such as Yarrowia lipolytica. To be accessible for microorganisms, the constituent sugars need to be released in a hydrolysis step, which as a side effect leads to the formation of various inhibitory compounds. However, the effects of these inhibitory compounds on the growth of Y. lipolytica have not been thoroughly investigated., Results: Here we show the individual and combined effect of six inhibitors from three major inhibitor groups on the growth of Y. lipolytica. We engineered a xylose consuming strain by overexpressing the three native genes XR, XDH, and XK and found that the inhibitor tolerance of Y. lipolytica is similar in glucose and in xylose. Aromatic compounds could be tolerated at high concentrations, while furfural linearly increased the lag phase of the cultivation, and hydroxymethylfurfural only inhibited growth partially. The furfural induced increase in lag phase can be overcome by an increased volume of inoculum. Formic acid only affected growth at concentrations above 25 mM. In a synthetic hydrolysate, formic acid, furfural, and coniferyl aldehyde were identified as the major growth inhibitors., Conclusion: We showed the individual and combined effect of inhibitors found in hydrolysate on the growth of Y. lipolytica. Our study improves understanding of the growth limiting inhibitors found in hydrolysate and enables a more targeted engineering approach to increase the inhibitor tolerance of Y. lipolytica. This will help to improve the usage of Y. lipolytica as a sustainable microbial cell factory.

The present study was aimed to investigate the antibiofilm activity of 5-hydroxymethylfurfural against Acinetobacter baumanni and Vellar estuary isolates v3 (Acinetobacter nosocomialis). The biofilm inhibitory concentration (BIC) of 5HMF against A. baumannii and v3 (A. nosocomialis) was found to be 100 µg/ml) exhibited non-bactericidal concentration-dependent antibiofilm activities against Acinetobacter species. The present study found that 5HMF treatment is very effective in the initial stage of A. baumannii biofilms and it significantly disrupted the mature biofilms. Moreover, 5HMF treatment inhibited the extracellular polymeric substances (EPS), including polysaccharides and proteins production. Results from gene expression and in vitro assays further demonstrated the 5HMF treatment downregulated the expression of bfmR, bap, csuA/B, ompA and katE virulence genes, which consistently affects biofilm formation and its mediated virulence property. The present study suggests that 5HMF unveil its antibiofilm activity by interfering initial biofilm formation and suppressing the virulence regulator genes in A. baumannii. Further studies are required to explore the 5HMF mode of action responsible for the antibiofilm activity.

Electrogenic bacteria can mediate electron transfer to conserve energy and promote growth. To examine bacterial electrogenicity, an L. mesenteroides EH-1 strain was cultured in rich media in the presence and absence of 2% glucose. After 12 h incubation, glucose triggered fermentation of L. mesenteroides EH-1 to produce >10 mmol/l acetate and elicit electricity measured by voltage changes. The electricity production was mediated by glucose fermentation since pre-treatment of L. mesenteroides EH-1 with furfural, a fermentation inhibitor, completely diminished the voltage increases. The deficiency of furfural pre-treated L. mesenteroides EH-1 in electricity production can be restored by the external addition of acetate into the bacterial culture, suggesting the function of acetate as an electron donor. Oral administration of HFD-fed mice with L. mesenteroides EH-1 in the presence or absence of glucose significantly attenuated the high level of pro-inflammatory IL-6 cytokine in blood. Bacterial electricity can be elicited by fermentation. Supplementation of fermenting and electrogenic L. mesenteroides EH-1 may provide a novel approach for the reduction of pro-inflammatory IL-6 cytokine that increased in chronic inflammation, autoimmune diseases, cancers, and infections., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Pear juice concentrate prepared by boiling Japanese pear ( Pyrus pyrifolia Nakai cv. Nijisseiki) juice can significantly inhibit the activity of tyrosinase, a key enzyme in melanin synthesis in human skin. Using the ethanol extract of pear juice concentrate, we homogeneously purified an active compound that was identified as 5-hydroxymethyl-2-furaldehyde (5-HMF) through 1 H- and 13 C-NMR and mass spectroscopy. We observed that 5-HMF inhibited the monophenolase and diphenolase activities of mushroom tyrosinase as a mixed-type inhibitor ( K i values of 3.81 and 3.70 mmol/L, respectively). In B16 mouse melanoma cells, treatment with 170 µmol/L of 5-HMF significantly reduced α-melanocyte-stimulated melanin synthesis by suppressing the cyclic adenosine monophosphate-dependent signaling pathway involved in melanogenesis. The results of our study indicated that 5-HMF can be potentially used as a skin-lightening agent in the cosmetic industry. Abbreviations: AC: adenylate cyclase; CREB: cAMP response element-binding protein; dhFAME: S-(-)-10,11-Dihydroxyfarnesoic acid methyl ester; DMEM: dulbecco's modified eagle medium; l-DOPA: 3-(3,4-Dihydroxyphenyl)- l-alanine; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HEPES: 4-(2-Hydroxyethyl)-1-piperazine ethane sulfonic acid; 5-HMF: 5-Hydroxymethyl-2-furaldehyde; MITF: microphthalmia-associated transcription factor; α-MSH: α-Melanocyte-stimulating hormone; PKA: protein kinase A; PVDF: polyvinylidene difluoride; SDS: sodium dodecyl sulfate; TRP1: tyrosinase-related protein 1; TRP2: tyrosinase-related protein 2.

Zymomonas mobilis, as an ethanologenic microorganism with many desirable industrial features, faces crucial obstacles in the lignocellulosic ethanol production process. A significant hindrance occurs during the pretreatment procedure that not only produces fermentable sugars but also releases severe toxic compounds. As diverse parts of regulation networks are involved in different aspects of complicated tolerance to inhibitors, we developed ZM4-hfq and ZM4-sigE strains, in which hfq and sigE genes were overexpressed, respectively. ZM4-hfq is a transcription regulator and ZM4-sigE is a transcription factor that are involved in multiple stress responses. In the present work, by overexpressing these two genes, we evaluated their impact on the Z. mobilis tolerance to furfural, acetic acid, and sugarcane bagasse hydrolysates. Both recombinant strains showed increased growth rates and ethanol production levels compared to the parental strain. Under a high concentration of furfural, the growth rate of ZM4-hfq was more inhibited compared to ZM4-sigE. More precisely, fermentation performance of ZM4-hfq revealed that the yield of ethanol production was less than that of ZM4-sigE, because more unused sugar had remained in the medium. In the case of acetic acid, ZM4-sigE was the superior strain and produced four and two-fold more ethanol compared to the parental strain and ZM4-hfq, respectively. Comparison of inhibitor tolerance between single and multiple toxic inhibitors in the fermentation of sugarcane bagasse hydrolysate by ZM4-sigE strain showed similar results. In addition, ethanol production performance was considerably higher in ZM4-sigE as well. Finally, the results of the qPCR analysis suggested that under both furfural and acetic acid treatment experiments, overproduction of both hfq and sigE improves the Z. mobilis tolerance and its ethanol production capability. Overall, our study showed the vital role of the regulatory elements to overcome the obstacles in lignocellulosic biomass-derived ethanol and provide a platform for further improvement by directed evolution or systems metabolic engineering tools., Competing Interests: The authors have declared that no competing interests exist.

Nicotiana tabacum, Stemona japonica, and Cnidium monnieri are common plants that are widely used for their anti-parasitic properties. The purpose of this study was to evaluate the acaricidal activity of extracts from these plants against the brown dog tick, Rhipicephalus sanguineus. A composition analysis of crude extracts by GC-MS was conducted to discover compounds with acaricidal effects. The toxicity of extraction against the engorged nymphs of R. sanguineus was evaluated by an immersion test. The results showed that the crude extracts of S. japonica and C. monnieri in varying ratios, concentrations, and from different extraction methods, had a killing effect on R. sanguineus. Lethality reached 76.67% ± 0.04410 when using a 1:1 extract of S. japonica:C. monnieri in 75% ethanol with ultrasonic extraction; the crude extract was determined at a concentration of 0.5 g/mL. GC-MS results showed that osthole and 5-hydroxymethylfurfural (5-HMF) are the main components of the extract. These results suggested that ultrasound-assisted extraction (UAE) extracts contained acaricidal components acting against R. sanguineus, which may result in the development of effective extracts of S. japonica and C. monnieri as a source of low-toxicity, plant-based, natural acaricidal drugs., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Furfural and 5-hydroxymethyl furfural (5-HMF) are key furan inhibitors that are generated due to breakdown of lignocellulosic sugars at high temperature and acidic treatment conditions. Both furfural and 5-HMF act in a synergistic manner to inhibit microbial metabolism and resistance to both is a desirable characteristic for efficient conversion of lignocellulosic carbon to ethanol. Genetic manipulations targeted toward increasing cellular NADPH pools have successfully imparted tolerance against furfural and 5-HMF. In present study, deletion of pgi gene as a strategy to augment carbon flow through pentose phosphate pathway (PPP) was studied in ethanologenic Escherichia coli strain SSK101 to impart tolerance towards either furfural or 5-HMFor both inhibitors together., Results: A key gene of EMP pathway, pgi, was deleted in an ethanologenic E. coli strain SSK42 to yield strain SSK101. In presence of 1 g/L furfural in minimal AM1 media, the rate of biomass formation for strain SSK101 was up to 1.9-fold higher as compared to parent SSK42 strain, and it was able to clear furfural in half the time. Tolerance to inhibitor was associated with glucose as carbon source and not xylose, and the tolerance advantage of SSK101 was neutralized in LB media. Bioreactor studies were performed under binary stress of furfural and 5-HMF (1 g/L each) and different glucose concentrations in a glucose-xylose mixture with final sugar concentration of 5.5%, mimicking major components of dilute acid treated biomass hydrolysate. In the mixture having 6 g/L and 12 g/L glucose, SSK101 strain produced ~ 18 g/L and 20 g/L ethanol, respectively. Interestingly, the maximum ethanol productivity was better at lower glucose load with 0.46 g/(L.h) between 96 and 120 h, as compared to higher glucose load where it was 0.33 g/(L.h) between 144 and 168 h. Importantly, parent strain SSK42 did not exhibit significant metabolic activity under similar conditions of inhibitor load and sugar concentration., Conclusions: E. coli strain SSK101 with pgi deletion had enhanced tolerance against both furfural and 5-HMF, which was associated with presence of glucose in media. Strain SSK101 also had improved fermentation characteristics under both hyperosmotic as well as binary stress of furfural and 5-HMF in media containing glucose-xylose mixture.

Aquaporin-1 (AQP1) dual water and ion channels enhance migration and invasion when upregulated in leading edges of certain classes of cancer cells. Work here identifies structurally related furan compounds as novel inhibitors of AQP1 ion channels. 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, and three structurally related compounds, 5-nitro-2-furoic acid (5NFA), 5-acetoxymethyl-2-furaldehyde (5AMF), and methyl-5-nitro-2-furoate (M5NF), were analyzed for effects on water and ion channel activities of human AQP1 channels expressed in Xenopus oocytes. Two-electrode voltage clamp showed dose-dependent block of the AQP1 ion current by 5HMF (IC 50 0.43 mM), 5NFA (IC 50 1.2 mM), and 5AMF (IC 50 ∼3 mM) but no inhibition by M5NF. In silico docking predicted the active ligands interacted with glycine 165, located in loop D gating domains surrounding the intracellular vestibule of the tetrameric central pore. Water fluxes through separate intrasubunit pores were unaltered by the furan compounds (at concentrations up to 5 mM). Effects on cell migration, invasion, and cytoskeletal organization in vitro were tested in high-AQP1-expressing cancer lines, colon cancer (HT29) and AQP1-expressing breast cancer (MDA), and low-AQP1-expressing SW480. 5HMF, 5NFA, and 5AMF selectively impaired cell motility in the AQP1-enriched cell lines. In contrast, M5NF immobilized all the cancer lines by disrupting actin cytoskeleton. No reduction in cell viability was observed at doses that were effective in blocking motility. These results define furans as a new class of AQP1 ion channel inhibitors for basic research and potential lead compounds for development of therapeutic agents targeting aquaporin channel activity. SIGNIFICANCE STATEMENT: 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, blocks the ion conductance but not the water flux through human Aquaporin-1 (AQP1) channels and impairs AQP1-dependent cell migration and invasiveness in cancer cell lines. Analyses of 5HMT and structural analogs demonstrate a structure-activity relationship for furan compounds, supported by in silico docking modeling. This work identifies new low-cost pharmacological antagonists for AQP1 available to researchers internationally. Furans merit consideration as a new class of therapeutic agents for controlling cancer metastasis., (Copyright © 2020 by The American Society for Pharmacology and Experimental Therapeutics.)

Ginseng (G) and Prepared Rehmannia Root (PRR) are commonly used in traditional Chinese medicine for blood supplementation. This study aimed to study G and PRR with different compatibility ratios changes in chemical composition and inhibition of cyclophosphamide-induced myelosuppression. HPLC was used to determine the chemical constituents of 13 ginsenosides, 5-hydroxymethylfurfural (5-HMF) and verbascoside in different proportions of G-PRR. Balb/c mice were injected intraperitoneally with cyclophosphamide (CTX) to induce bone marrow suppression. The effects of different proportions of G-PRR on peripheral blood, bone marrow nucleated cells, thymus and spleen index of myelosuppressed mice were analyzed. The results showed that the compatibility of G and PRR can promote the dissolution of ginsenosides, and the content of conventional ginsenosides decreased, and the content of rare ginsenosides increased. Different proportions of G-PRR increased the number of peripheral blood and bone marrow nucleated cells in cyclophosphamide-induced bone marrow suppression mice (p < 0.01), increased thymus index (p < 0.01), decreased spleen index (p < 0.01). Different proportions of G-PRR can improve the myelosuppression induced by cyclophosphamide in mice, and the combined effect of G-PRR is better than the single decoction of G and PRR. Among them, G-PRR 2 : 3 and G-PRR 1 : 2 were better than the other groups. These results indicate that different proportion of G-PRR can improve bone marrow suppression, and the combined decoction of G-PRR is better than the separate Decoction in improving bone marrow suppression. This improvement may be related to the changes of the substance basis and active ingredients of G-PRR.

The incidence of adverse reactions in food is very low, however, some food products contain toxins formed naturally due to their handling, processing and storage conditions. 5-(Hydroxymethyl)-2-furfural (HMF) can be formed by hydrogenation of sugar substances in some of manufactured foodstuffs and honey under elevated temperatures and reduced pH conditions following Maillard reactions. In previous studies, it was found that HMF was responsible for harmful (mutagenic, genotoxic, cytotoxic and enzyme inhibitory) effects on human health. HMF occurs in a wide variety of food products like dried fruit, juice, caramel products, coffee, bakery, malt and vinegar. The formation of HMF is not only an indicator of food storage conditions and quality, but HMF could also be used as an indicator of the potential occurrence of contamination during heat-processing of some food products such as coffee, milk, honey and processed fruits. This review focuses on HMF formation and summarizes the adverse effects of HMF on human health.

Jabara ( Citrus jabara Hort. ex Y. Tanaka) is a type of citrus fruit known for its beneficial effect against seasonal allergies. Jabara is rich in the antioxidant narirutin whose anti-allergy effect has been demonstrated. One of the disadvantages in consuming Jabara is its bitter flavor. Therefore, we fermented the fruit to reduce the bitterness and make Jabara easy to consume. Here, we examined whether fermentation alters the anti-allergic property of Jabara. Suppression of degranulation and cytokine production was observed in mast cells treated with fermented Jabara and the effect was dependent on the length of fermentation. We also showed that 5-hydroxymethylfurfural (5-HMF) increases as fermentation progresses and was identified as an active component of fermented Jabara, which inhibited mast cell degranulation. Mast cells treated with 5-HMF also exhibited reduced degranulation and cytokine production. In addition, we showed that the expression levels of phospho-PLC γ 1 and phospho-ERK1/2 were markedly reduced upon FcεRI stimulation. These results indicate that 5-HMF is one of the active components of fermented Jabara that is involved in the inhibition of mast cell activation.

The industrial yeast Saccharomyces cerevisiae has a plastic genome with a great flexibility in adaptation to varied conditions of nutrition, temperature, chemistry, osmolarity, and pH in diversified applications. A tolerant strain against 2-furaldehyde (furfural) and 5-hydroxymethyl-2-furaldehyde (HMF) was successfully obtained previously by adaptation through environmental engineering toward development of the next-generation biocatalyst. Using a time-course comparative transcriptome analysis in response to a synergistic challenge of furfural-HMF, here we report tolerance phenotypes of pathway-based transcriptional profiles as components of the adapted defensive system for the tolerant strain NRRL Y-50049. The newly identified tolerance phenotypes were involved in biosynthesis superpathway of sulfur amino acids, defensive reduction-oxidation reaction process, cell wall response, and endogenous and exogenous cellular detoxification. Key transcription factors closely related to these pathway-based components, such as Yap1, Met4, Met31/32, Msn2/4, and Pdr1/3, were also presented. Many important genes in Y-50049 acquired an enhanced transcription background and showed continued increased expressions during the entire lag phase against furfural-HMF. Such signature expressions distinguished tolerance phenotypes of Y-50049 from the innate stress response of its progenitor NRRL Y-12632, an industrial type strain. The acquired yeast tolerance is believed to be evolved in various mechanisms at the genomic level. Identification of legitimate tolerance phenotypes provides a basis for continued investigations on pathway interactions and dissection of mechanisms of yeast tolerance and adaptation at the genomic level.

Sickle cell trait (SCT) is the benign heterozygous carrier state for the sickle variant of the HBB gene. Most of the ~300 million people with SCT worldwide will not experience any significant complications. However, accumulating evidence finds SCT associated with increased risk for the common conditions of chronic kidney disease and venous thromboembolism, and severe but rare renal medullary carcinoma and exercise-induced rhabdomyolysis. The mechanism is uncertain, but probably involves pathological rheology of SCT blood in regions of low oxygen tension, resulting from sickle haemoglobin polymerization in SCT red cells and leading to reduced blood flow and further tissue hypoxia and damage. Here, we used an in vitro microfluidic flow system to study the oxygen-dependent rheology of SCT blood and show that 5-(hydroxymethyl)furfural, a natural breakdown product of glucose and fructose-containing foods, such as fruit juices, can reduce the effects of hypoxia on SCT blood rheology in vitro, restoring near-normal flow velocities at very low oxygen. While opinions regarding the clinical significance of the risks associated with SCT are still evolving, these results suggest that a compound present in some food may provide a potential approach for managing risks that may be associated with SCT., (© 2019 British Society for Haematology and John Wiley & Sons Ltd.)

Ethnopharmacological Relevance: Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines., Aim of the Study: To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa., Materials and Methods: The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml -1 concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa., Results: MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml -1 concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml -1 concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa., Conclusion: This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections., (Copyright © 2019. Published by Elsevier B.V.)

We developed a significantly improved ultra-high performance liquid chromatography-tandem mass spectrometry method for determination of 5-nitro-2-furaldehyde (NF) as a surrogate using a novel internal standard for the detection of nitrofurazone. We used 2,4-dinitrophenylhydrazine derivatization and furfural as the internal standard. Derivatization was easily performed in HCl using ultrasonic manipulation for 5 min followed by liquid extraction using ethyl acetate. The samples were concentrated and purified using reverse phase and alumina cartridges in tandem. The derivatives were separated using a linear gradient elution on a C 18 column with methanol and water as the mobile phase in negative ionization mode and multiple reaction monitoring. Under the optimized conditions, the calibration curves were linear from 0.2 to 20 μg/L with correlation coefficients >0.999. Mean recoveries were 80.8 to 104.4% with the intra- and inter-day relative standard deviations <15% at spiking levels of 0.1 to 10 μg/kg. The limits of detection and quantification were 0.05 and 0.1 μg/kg, respectively. This method is a robust tool for the identification and quantitative determination of NF in shrimp samples.