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Abstract Background Benzoic acid is one of the most useful aromatic compounds. Despite its versatility and simple structure, benzoic acid production using microbes has not been reported previously. Streptomyces are aerobic, Gram-positive, mycelia-forming soil bacteria, and are known to produce various kinds of antibiotics composed of many aromatic residues. S. maritimus possess a complex amino acid modification pathway and can serve as a new platform microbe to produce aromatic building-block compounds. In this study, we carried out benzoate fermentation using S. maritimus. In order to enhance benzoate productivity using cellulose as the carbon source, we constructed endo-glucanase secreting S. maritimus. Results After 4 days of cultivation using glucose, cellobiose, or starch as a carbon source, the maximal level of benzoate reached 257, 337, and 460 mg/l, respectively. S. maritimus expressed β-glucosidase and high amylase-retaining activity compared to those of S. lividans and S. coelicolor. In addition, for effective benzoate production from cellulosic materials, we constructed endo-glucanase-secreting S. maritimus. This transformant efficiently degraded the phosphoric acid swollen cellulose (PASC) and then produced 125 mg/l benzoate. Conclusions Wild-type S. maritimus produce benzoate via a plant-like β-oxidation pathway and can assimilate various carbon sources for benzoate production. In order to encourage cellulose degradation and improve benzoate productivity from cellulose, we constructed endo-glucanase-secreting S. maritimus. Using this transformant, we also demonstrated the direct fermentation of benzoate from cellulose. To achieve further benzoate productivity, the L-phenylalanine availability needs to be improved in future.

Abstract Background Hydrolysis of cellulose requires the action of the cellulolytic enzymes endoglucanase, cellobiohydrolase and β-glucosidase. The expression ratios and synergetic effects of these enzymes significantly influence the extent and specific rate of cellulose degradation. In this study, using our previously developed method to optimize cellulase-expression levels in yeast, we constructed a diploid Saccharomyces cerevisiae strain optimized for expression of cellulolytic enzymes, and attempted to improve the cellulose-degradation activity and enable direct ethanol production from rice straw, one of the most abundant sources of lignocellulosic biomass. Results The engineered diploid strain, which contained multiple copies of three cellulase genes integrated into its genome, was precultured in molasses medium (381.4 mU/g wet cell), and displayed approximately six-fold higher phosphoric acid swollen cellulose (PASC) degradation activity than the parent haploid strain (63.5 mU/g wet cell). When used to ferment PASC, the diploid strain produced 7.6 g/l ethanol in 72 hours, with an ethanol yield that achieved 75% of the theoretical value, and also produced 7.5 g/l ethanol from pretreated rice straw in 72 hours. Conclusions We have developed diploid yeast strain optimized for expression of cellulolytic enzymes, which is capable of directly fermenting from cellulosic materials. Although this is a proof-of-concept study, it is to our knowledge, the first report of ethanol production from agricultural waste biomass using cellulolytic enzyme-expressing yeast without the addition of exogenous enzymes. Our results suggest that combining multigene expression optimization and diploidization in yeast is a promising approach for enhancing ethanol production from various types of lignocellulosic biomass.

Abstract Background The filamentous fungus T. reesei effectively degrades cellulose and is known to produce various cellulolytic enzymes such as β-glucosidase, endoglucanase, and cellobiohydrolase. The expression levels of each cellulase are controlled simultaneously, and their ratios and synergetic effects are important for effective cellulose degradation. However, in recombinant Saccharomyces cerevisiae, it is difficult to simultaneously control many different enzymes. To construct engineered yeast with efficient cellulose degradation, we developed a simple method to optimize cellulase expression levels, named cocktail δ-integration. Results In cocktail δ-integration, several kinds of cellulase expression cassettes are integrated into yeast chromosomes simultaneously in one step, and strains with high cellulolytic activity (i.e., expressing an optimum ratio of cellulases) are easily obtained. Although the total integrated gene copy numbers of cocktail δ-integrant strain was about half that of a conventional δ-integrant strain, the phosphoric acid swollen cellulose (PASC) degradation activity (64.9 mU/g-wet cell) was higher than that of a conventional strain (57.6 mU/g-wet cell). This suggests that optimization of the cellulase expression ratio improves PASC degradation activity more so than overexpression. Conclusions To our knowledge, this is the first report on the expression of cellulase genes by δ-integration and optimization of various foreign genes by δ-integration in yeast. This method should be very effective and easily applied for other multi-enzymatic systems using recombinant yeast.

Pretreatment of lignocellulosic biomass is crucial yet challenging for sustainable energy production. This study focuses on enhancing enzymatic accessibility of cellulose in oil palm empty fruit bunches by optimizing pretreatment parameters to improve glucose and ethanol yields while reducing fermentation inhibitors. It evaluates the impact of maleic acid concentrations on biorefinery processes. High maleic acid concentrations (>25% w/w) may allow reuse and offer benefits over lower concentrations, such as enhanced delignification and increased sugar yield under milder conditions. Biomass undergoes pretreatment, enzymatic saccharification, and fermentation using Saccharomyces cerevisiae F118. Pretreatment with 75% maleic acid (w/w) for 60 min at 180 °C effectively removes lignin and hemicellulose, increasing cellulose accessibility but results in 74.8% crystallinity, hindering saccharification. A 50% maleic acid pretreatment yielded higher glucose (77.1%). Optimal ethanol production is achieved with 1% maleic acid pretreatment. However, the ethanol yield is negatively impacted by residual maleic acid on the solid matrix., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Background: Adaptive laboratory evolution (ALE) is an impactful technique for cultivating microorganisms to adapt to specific environmental circumstances or substrates through iterative growth and selection. This study utilized an adaptive laboratory evolution method on Lipomyces starkeyi for high tolerance in producing lignin derivative alcohols and lipids from syringaldehyde. Afterward, untargeted metabolomics analysis was employed to find the key metabolites that play important roles in the better performance of evolved strains compared to the wild type. Lignin, a prominent constituent of plant biomass, is a favorable source material for the manufacture of biofuel and lipids. Nevertheless, the effective transformation of chemicals produced from lignin into products with high economic worth continues to be a difficult task., Results: In this study, we exposed L. starkeyi to a series of flask passaging experiments while applying selective pressure to facilitate its adaptation to syringaldehyde, a specific type of lignin monomeric aldehyde. Using ALE, we successfully developed a new strain, DALE-22, which can synthesize syringyl alcohol up to 18.74 mM from 22.28 mM syringaldehyde with 41.9% lipid accumulation. In addition, a comprehensive examination of untargeted metabolomics identified six specific crucial metabolites linked to the improved tolerance of the evolved strain in the utilization of syringaldehyde, including 2-aminobutyric acid, allantoin, 4-hydroxyphenethyl alcohol, 2-aminoethanol, tryptophan, and 5-aminovaleric acid., Conclusion: The results of our study reveal how L. starkeyi adapts to using substrates produced from lignin. These findings offer important information for developing strategies to improve the process of converting lignin into valuable products for sustainable biorefinery applications., (© 2024. The Author(s).)

This research aims to create an emulsion formulation utilizing lignin as a carrier and citronella oil for its application as a herbicide. The formulation composition includes lignin solution 55-62 %v/v, Tween 80 25 %w/v, propylene glycol 10 %w/v, and citronella oil 3-10 %w/v. The preparation steps involve preparing the oil phase by mixing tween 80 surfactant, propylene glycol, and citronella oil; preparing the aqueous phase by mixing lignin into distilled water at pH 12 with stirring; mixing the oil phase and the water phase accompanied by stirring at 5000-10000 rpm for 1-5 minutes until a stable solution is formed as a natural herbicide. The application outcomes revealed that the formulation successfully eliminated specific weeds within two to three days at the maximum concentration of 10 %, leaving no detectable herbicide residue after 7 and 15 days of treatment. The result demonstrates how green technology has the capacity to replace herbicides derived from chemicals, especially in the agricultural sector., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Only a few reports available about the assimilation of hydrophobic or oil-based feedstock as carbon sources by Lipomyces starkeyi. In this study, the ability of L. starkeyi to efficiently utilize free fatty acids (FFAs) and real biomass like palm acid oil (PAO) as well as crude palm kernel oil (CPKO) for growth and lipid production was investigated. PAO, CPKO, and FFAs were evaluated as sole carbon sources or in the mixed medium containing glucose. L. starkeyi was able to grow on the medium supplemented with PAO and FFAs, which contained long-chain length FAs and accumulated lipids up to 35% (w/w) of its dry cell weight. The highest lipid content and lipid concentration were achieved at 50% (w/w) and 10.1 g/L, respectively, when L. starkeyi was cultured in nitrogen-limited mineral medium (-NMM) supplemented with PAO emulsion. Hydrophobic substrate like PAO could be served as promising carbon source for L. starkeyi., (Copyright © 2024 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Previously, we biosynthesized an evolved version of a bio-based polylactide (PLA) on microbial platforms using our engineered lactate-polymerizing enzyme (LPE). This lactate (LA)-based copolyester, LAHB, has advantages over PLA, including improved flexibility and biodegradability, and its properties can be regulated through the LA fraction. To expand the LA-incorporation capacity and improve polymer properties, in the state of in vivo LAHB production, propionyl-CoA transferases (PCTs) that exhibited enhanced production of LA-CoA than the conventional PCTs were selected. Here, the present study has demonstrated that the LA fraction of LAHB could be altered using various PCTs. Enhanced PCT performance was achieved by balancing polymer production and cell growth. Both events are governed by the use of acetyl-CoA, a commonly shared key metabolite. This could be attributed to the different reactivities of individual PCTs towards acetyl-CoA, which serves both as a CoA donor and a leading compound in the TCA cycle. Interestingly, we found complete sequence randomness in the LAHB copolymers, independent of the LA fraction. The mechanism of LA fraction-independent sequence randomness is discussed. This new PCT-based strategy synergistically combines with the evolution of LPE to advance the LAHB project, and enables us to perform advanced applications other than LAHB production utilizing CoA-linked substrates., Competing Interests: Declaration of competing interest Seiichi Taguchi reports financial support was provided by New Energy and Industrial Technology Development Organization of Japan. Seiichi Taguchi reports financial support was provided by JST Adaptable and Seamless Technology Transfer Program Through Target-driven R and D. If there are other authors, they 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 The Author(s). Published by Elsevier B.V. All rights reserved.)

The utilization of Streptomyces as a microbial chassis for developing innovative drugs and medicinal compounds showcases its capability to produce bioactive natural substances. Recent focus on the clustered regularly interspaced short palindromic repeat (CRISPR) technology highlights its potential in genome editing. However, applying CRISPR technology in certain microbial strains, particularly Streptomyces , encounters specific challenges. These challenges include achieving efficient gene expression and maintaining genetic stability, which are critical for successful genome editing. To overcome these obstacles, an innovative approach has been developed that combines several key elements: activation-induced cytidine deaminase (AID), nuclease-deficient cas9 variants (dCas9), and Petromyzon marinus cytidine deaminase 1 (PmCDA1). In this study, this novel strategy was employed to engineer a Streptomyces coelicolor strain. The target gene was actVA-ORF4 (SCO5079), which is involved in actinorhodin production. The engineering process involved introducing a specific construct [pGM1190-dcas9-pmCDA-UGI-AAV-actVA-ORF4 (SCO5079)] to create a CrA10 mutant strain. The resulting CrA10 mutant strain did not produce actinorhodin. This outcome highlights the potential of this combined approach in the genetic manipulation of Streptomyces . The failure of the CrA10 mutant to produce actinorhodin conclusively demonstrates the success of gene editing at the targeted site, affirming the effectiveness of this method for precise genetic modifications in Streptomyces ., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Engineering in Life Sciences published by Wiley‐VCH GmbH.)

While flocculation has demonstrated its efficacy in enhancing yeast robustness and ethanol production, its potential application for lactic acid fermentation remains largely unexplored. Our study examined the differences between flocculating and nonflocculating Saccharomyces cerevisiae strains in terms of their metabolic dynamics when incorporating an exogenous lactic acid pathway, across varying cell densities and in the presence of lignocellulose-derived byproducts. Comparative gene expression profiles revealed that cultivating a nonflocculant strain at higher cell density yielded a substantial upregulation of genes associated with glycolysis, energy metabolism, and other key pathways, resulting in elevated levels of fermentation products. Meanwhile, the flocculating strain displayed an inherent ability to sustain high glycolytic activity regardless of the cell density. Moreover, our investigation revealed a significant reduction in glycolytic activity under chemical stress, potentially attributable to diminished ATP supply during the energy investment phase. Conversely, the formation of flocs in the flocculating strain conferred protection against toxic chemicals present in the medium, fostering more stable lactic acid production levels. Additionally, the distinct flocculation traits observed between the two examined strains may be attributed to variations in the nucleotide sequences of the flocculin genes and their regulators. This study uncovers the potential of flocculation for enhanced lactic acid production in yeast, offering insights into metabolic mechanisms and potential gene targets for strain improvement., (© 2023 John Wiley & Sons Ltd.)

Itaconic acid is a promising biochemical building block that can be used in polymer synthesis. Itaconic acid is currently produced in industry by the natural producer fungus Aspergillus terreus using glucose as a main carbon source. Most research for itaconic acid production using lignocellulosic-based carbon sources was carried out by A. terreus. Engineered Corynebacterium glutamicum strain which can grow in presence of fermentation inhibitors without effect on growth, was used for production of itaconic acid using sweet sorghum juice and bagasse sugar lysate (BSL). BSL contains many inhibitors unlike sorghum juice. C. glutamicum could grow in the media containing both types of lignocellulose-based carbon sources without showing any growth inhibition, however, sorghum juice was better in itaconic acid production than BSL. Different constructed strains of C. glutamicum were used for itaconic acid production, however, C. glutamicum ATCC 13032 pCH-Tad1 opt Adi1 opt strain expressing Adi1/Tad1 genes (trans-pathway) from Ustilago maydis proved to be better in itaconic acid production giving final titer of 8.4 and 4.02 g/L using sweet sorghum juice and BSL as the sole carbon sources by fed-batch fermentation. Our study is the first for production of itaconic acid using sweet sorghum juice and BSL. The present study also proved that C. glutamicum can be used for enhancing itaconic acid production using lignocellulosic-based carbon sources., 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 Elsevier Inc. All rights reserved.)

Plants produce sugars by photosynthesis and use them for growth and development. Sugars are transported from source-to-sink organs via the phloem in the vasculature. It is well known that vascular development is precisely controlled by plant hormones and peptide hormones. However, the role of sugars in the regulation of vascular development is poorly understood. In this study, we examined the effects of sugars on vascular cell differentiation using a vascular cell induction system named 'Vascular Cell Induction Culture System Using Arabidopsis Leaves' (VISUAL). We found that sucrose has the strongest inhibitory effect on xylem differentiation, among several types of sugars. Transcriptome analysis revealed that sucrose suppresses xylem and phloem differentiation in cambial cells. Physiological and genetic analyses suggested that sucrose might function through the BRI1-EMS-SUPPRESSOR1 transcription factor, which is the central regulator of vascular cell differentiation. Conditional overexpression of cytosolic invertase led to a decrease in the number of cambium layers due to an imbalance between cell division and differentiation. Taken together, our results suggest that sucrose potentially acts as a signal that integrates environmental conditions with the developmental program., (© The Author(s) 2023. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Itaconic acid (IA), a C5-dicarboxylic acid, is a potential bio-based building block for the polymer industry. There are three pathways for IA production from natural IA producers; however, most of the engineered strains were used for IA production by heterologous expression of cis-aconitate decarboxylase gene (cadA) from Aspergillus terreus. In this study, IA was produced by an engineered Corynebacterium glutamicum ATCC 13032 expressing two different types of genes from two distinct pathways. The first involves the mammalian immunoresponsive gene1 (Irg1) derived from Mus musculus. The second (termed here the trans-pathway) involves two genes from the natural IA producer Ustilago maydis which are aconitate-delta-isomerase (Adi1) and trans-aconitate decarboxylase (Tad1) genes. The constructed strains developing the two distinct IA production pathways: C. glutamicum ATCC 13032 pCH-Irg1 opt and C. glutamicum ATCC 13032 pCH-Tad1 opt adi1 opt were used for production of IA from different carbon sources. The results reflect the possibility for IA production from C. glutamicum expressing the trans-pathway (Adi1/Tad1 genes) and cis-pathway (Irg1 gene) other than the well-known cis-pathway that depends mainly on cadA gene from A. terreus. The developed strain expressing trans-pathway from U. maydis; however, proved to be better at IA production with high titers of 12.25, 11.34, and 11.02 g/L, and a molar yield of 0.22, 0.42, and 0.43 mol/mol from glucose, maltose, and sucrose, respectively, via fed-batch fermentation. The present study suggests that trans-pathway is better than cis-pathway for IA production in engineered C. glutamicum., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Itaconic acid (IA) is a value-added chemical currently produced by Aspergillus terreus from edible glucose and starch but not from inedible lignocellulosic biomass owing to the high sensitivity to fermentation inhibitors present in the hydrolysate of lignocellulosic biomass. To produce IA from lignocellulosic biomass, a gram-positive bacterium, Corynebacterium glutamicum, with a high tolerance to fermentation inhibitors was metabolically engineered to express a fusion protein composed of cis-aconitate decarboxylase from A. terreus responsible for IA formation from cis-aconitate and a maltose-binding protein (malE) from Escherichia coli. The codon-optimized cadA_malE gene was expressed in C. glutamicum ATCC 13032, and the resulting recombinant strain produced IA from glucose. IA concentration increased 4.7-fold by the deletion of the ldh gene encoding lactate dehydrogenase. With the Δldh strain HKC2029, an 18-fold higher IA production was observed from enzymatic hydrolysate of kraft pulp as a model lignocellulosic biomass than from glucose (6.15 and 0.34 g/L, respectively). The enzymatic hydrolysate of kraft pulp contained various potential fermentation inhibitors involved in furan aldehydes, benzaldehydes, benzoic acids, cinnamic acid derivatives, and aliphatic acid. Whereas cinnamic acid derivatives severely inhibited IA production, furan aldehydes, benzoic acids, and aliphatic acid improved IA production at low concentrations. The present study suggests that lignocellulosic hydrolysate contains various potential fermentation inhibitors; however, some of them can serve as enhancers for microbial fermentation likely due to the changing of redox balance in the cell., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Inorganic nanoparticles with multiple functions have been attracting attention as multimodal nanoprobes in bioimaging, biomolecule detection, and medical diagnosis and treatment. A drawback of conventional metallic nanoparticle-based nanoprobes is the Ohmic losses that lead to fluorescence quenching of attached molecules and local heating under light irradiation. Here, metal-free nanoprobes capable of scattering/fluorescence dual-mode imaging are developed. The nanoprobes are composed of a silicon nanosphere core having efficient Mie scattering in the visible to near infrared range and a fluorophore doped silica shell. The dark-field scattering and photoluminescence images/spectra for nanoprobes made from different size silicon nanospheres and different kinds of fluorophores are studied by single particle spectroscopy. The fluorescence spectra are strongly modified by the Mie modes of a silicon nanosphere core. By comparing scattering and fluorescence spectra and calculated Purcell factors, the fluorescence enhancement factor is quantitatively discussed. In vitro scattering/fluorescence imaging studies on human cancer cells demonstrate that the developed nanoparticles work as scattering/fluorescence dual-mode imaging nanoprobes., (© 2023 Wiley-VCH GmbH.)

Sorghum is the fifth most important cereal crop. Here we performed molecular genetic analyses of the 'SUGARY FETERITA' (SUF) variety, which shows typical sugary endosperm traits (e.g., wrinkled seeds, accumulation of soluble sugars, and distorted starch). Positional mapping indicated that the corresponding gene was located on the long arm of chromosome 7. Within the candidate region of 3.4 Mb, a sorghum ortholog for maize Su1 ( SbSu ) encoding a starch debranching enzyme ISA1 was found. Sequencing analysis of SbSu in SUF uncovered nonsynonymous single nucleotide polymorphisms (SNPs) in the coding region, containing substitutions of highly conserved amino acids. Complementation of the rice sugary-1 ( osisa1 ) mutant line with the SbSu gene recovered the sugary endosperm phenotype. Additionally, analyzing mutants obtained from an EMS-induced mutant panel revealed novel alleles with phenotypes showing less severe wrinkles and higher Brix scores. These results suggested that SbSu was the corresponding gene for the sugary endosperm. Expression profiles of starch synthesis genes during the grain-filling stage demonstrated that a loss-of-function of SbSu affects the expression of most starch synthesis genes and revealed the fine-tuned gene regulation in the starch synthetic pathway in sorghum. Haplotype analysis using 187 diverse accessions from a sorghum panel revealed the haplotype of SUF showing severe phenotype had not been used among the landraces and modern varieties. Thus, weak alleles (showing sweet and less severe wrinkles), such as in the abovementioned EMS-induced mutants, are more valuable for grain sorghum breeding. Our study suggests that more moderate alleles ( e.g. produced by genome editing) should be beneficial for improving grain sorghum., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hashimoto, Okada, Araki-Nakamura, Ohmae-Shinohara, Miura, Kawaguchi, Ogino, Kasuga and Sazuka.)

Lignocellulose is resistant to degradation and requires pretreatment before hydrolytic enzymes can release fermentable sugars. Sulfuric acid has been widely used for biomass pretreatment, but high amount of degradation products usually occurred when using this method. To enhance accessibility to cellulose, we studied the performances of several dilute organic acid pretreatments of sugarcane bagasse and oil palm empty fruit bunch fiber. The results revealed that pretreatment with maleic acid yields the highest xylose and glucose release among other organic acids. The effects of concentration, duration of heating and heating temperature were further studied. Dilute maleic acid 1 % (w/w) pretreatment at 180 °C was the key to its viability as a substitute for sulfuric acid. Moreover, maleic acid did not seem to highly promote the formation of either furfural or 5-HMF in the liquid hydrolysate after pretreatment., 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 © 2022 Elsevier Ltd. All rights reserved.)

New enzyme functions exist within the increasing number of unannotated protein sequences. Novel enzyme discovery is necessary to expand the pathways that can be accessed by metabolic engineering for the biosynthesis of functional compounds. Accordingly, various machine learning models have been developed to predict enzymatic reactions. However, the ability to predict unknown reactions that are not included in the training data has not been clarified. In order to cover uncertain and unknown reactions, a wider range of reaction types must be demonstrated by the models. Here, we establish 16 expanded enzymatic reaction prediction models developed using various machine learning algorithms, including deep neural network. Improvements in prediction performances over that of our previous study indicate that the updated methods are more effective for the prediction of enzymatic reactions. Overall, the deep neural network model trained with combined substrate-enzyme-product information exhibits the highest prediction accuracy with Macro F 1 scores up to 0.966 and with robust prediction of unknown enzymatic reactions that are not included in the training data. This model can predict more extensive enzymatic reactions in comparison to previously reported models. This study will facilitate the discovery of new enzymes for the production of useful substances.

The aromatic compound 3-amino-4-hydroxybenzoic acid (3,4-AHBA) can be employed as a raw material for high-performance industrial plastics. The aim of this study is to produce 3,4-AHBA via a recombinant Streptomyces lividans strain containing griI and griH genes derived from Streptomyces griseus using culture medium with glucose and/or xylose, which are the main components in lignocellulosic biomass. Production of 3,4-AHBA by the recombinant S. lividans strain was successful, and the productivity was affected by the kind of sugar used as an additional carbon source. Metabolic profiles revealed that L aspartate-4-semialdehyde (ASA), a precursor of 3,4-AHBA, and coenzyme NADPH were supplied in greater amounts in xylose medium than in glucose medium. Moreover, cultivation in TSB medium with a mixed sugar (glucose/xylose) was found to be effective for 3,4-AHBA production, and optimal conditions for efficient production were designed by changing the ratio of glucose to xylose. The best productivity of 2.70 g/L was achieved using a sugar mixture of 25 g/L glucose and 25 g/L xylose, which was 1.5 times higher than the result using 50 g/L glucose alone. These results suggest that Streptomyces is a suitable candidate platform for 3,4-AHBA production from lignocellulosic biomass-derived sugars under appropriate culture conditions.

Acidic and chemical inhibitor stresses undermine efficient lactic acid bioproduction from lignocellulosic feedstock. Requisite coping treatments, such as detoxification and neutralizing agent supplementation, can be eliminated if a strong microbial host is employed in the process. Here, we exploited an originally robust yeast, Saccharomyces cerevisiae BTCC3, as a production platform for lactic acid. This wild-type strain exhibited a rapid cell growth in the presence of various chemical inhibitors compared to laboratory and industrial strains, namely BY4741 and Ethanol-red. Pathway engineering was performed on the strain by introducing an exogenous LDH gene after disrupting the PDC1 and PDC5 genes. Facilitated by this engineered strain, high cell density cultivation could generate lactic acid with productivity at 4.80 and 3.68 g L -1  h -1 under semi-neutralized and non-neutralized conditions, respectively. Those values were relatively higher compared to other studies. Cultivation using real lignocellulosic hydrolysate was conducted to assess the performance of this engineered strain. Non-neutralized fermentation using non-detoxified hydrolysate from sugarcane bagasse as a medium could produce lactic acid at 1.69 g L -1  h -1 , which was competitive to the results from other reports that still included detoxification and neutralization steps in their experiments. This strategy could make the overall lactic acid bioproduction process simpler, greener, and more cost-efficient., (© 2022. The Author(s).)

When lignocellulosic biomass is utilized as a fermentative substrate to produce biochemicals, the existence of a yeast strain resistant to inhibitory chemical compounds (ICCs) released from the biomass becomes critical. To achieve the purpose, in this study, Saccharomyces yeast strains from a NBRC yeast culture collection were used for exploration and evaluated in two different media containing ICCs that mimic one another but resemble the hydrolysate of real biomass. Among them, S. cerevisiae F118 strain shows robustness upon the fermentation with unique flocculation trait that was strongly responsive to ICC stress. When this strain was cultured in the presence of ICCs, its cell wall hydrophobicity increased dramatically, and reduced significantly when the ICCs were depleted, demonstrating that cell-surface hydrophobicity can also act as an adaptive response to the ICCs. Cells from the strain with the highest cell-wall hydrophobicity displayed progressively stronger flocculation, indicating that the F118 strain is having unique robustness under ICC stress. Gene expression perturbation analysis revealed that mot3 gene encoding regulatory Mot3p from the F118 strain was expressed in response to the concentration of ICCs. This gene was found to control expression of ygp1 gene that encoding Ygp1p, one of cell wall proteins. Deep sequencing analysis revealed that the Mot3p of the F118 strain features a unique insertion and deletion of nucleotides that encode glutamine or asparagine residues, particularly in N-terminal domain, as determined by comparison to the Mot3p sequence from the S288c strain, which was employed as a control strain. Furthermore, the cell wall hydrophobicity of the S288c strain was greatly enhanced and became ICC-responsive after gene swapping with the mot3 gene from the F118 strain. The gene-swapped S288c strain fermented 6-fold faster than the wild-type strain, producing 14.5 g/L of ethanol from 30 g/L of glucose consumed within 24 h in a medium containing the ICCs. These such modifications to Mot3p in unique locations in its sequence have a potential to change the expression of a gene involved in cell wall hydrophobicity and boosted the flocculation response to ICC stress, allowing for the acquisition of extraordinary robustness., (Copyright © 2022 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.)

Background: Despite recent advances in radiotherapy, radioresistance in patients with pancreatic cancer remains a crucial dilemma for clinical treatment. Cancer stem cells (CSCs) represent a major factor in radioresistance. Developing a potent radiosensitizer may be a novel candidate for the eradication of pancreatic CSCs., Methods: CSCs were isolated from MIA PaCa-2 and PANC1 human pancreatic cancer cell lines. Titanium peroxide nanoparticles (TiOxNPs) were synthesized from titanium dioxide nanoparticles (TiO 2 NPs) and utilized as radiosensitizers when added one hour prior to radiation exposure. The antitumor activity of this novel therapeutic strategy was evaluated against well-established pancreatic CSCs model both in vitro and in vivo., Results: It is shown that TiOxNPs combined with ionizing radiation exhibit anti-cancer effects on radioresistant CSCs both in vitro and in vivo. TiOxNPs exhibited a synergistic effect with radiation on pancreatic CSC-enriched spheres by downregulating self-renewal regulatory factors and CSC surface markers. Moreover, combined treatment suppressed epithelial-mesenchymal transition, migration, and invasion properties in primary and aggressive pancreatic cancer cells by reducing the expression of proteins relevant to these processes. Notably, radiosensitizing TiOxNPs suppressed the growth of pancreatic xenografts following primary or dissociating sphere MIA PaCa-2 cell implantation. It is inferred that synergy is formed by generating intolerable levels of reactive oxygen species (ROS) and inactivating the AKT signaling pathway., Conclusions: Our data suggested the use of TiOxNPs in combination with radiation may be considered an attractive therapeutic strategy to eliminate pancreatic CSCs., (© 2022. The Author(s).)

Each year, the palm oil industry generates a significant amount of biomass residue and effluent waste; both have been identified as significant sources of greenhouse gas (GHG) emissions. This issue poses a severe environmental challenge for the industry due to the possibility of long-term negative effects on human well-being. The palm-oil industry must invest significantly in the technology that is required to resolve these issues and to increase the industry's sustainability. However, current technologies for converting wastes such as lignocellulosic components and effluents into biochemical products are insufficient for optimal utilization. This review discusses the geographical availability of palm-oil biomass, its current utilization routes, and then recommends the development of technology for converting palm-oil biomass into value-added products through an integrated biorefinery strategy. Additionally, this review summarizes the palm oil industry's contribution to achieving sustainable development goals (SDGs) through a circular bioeconomy concept., (Copyright © 2021 Elsevier Ltd. All rights reserved.)