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Magnetic Fe 3 O 4 nanoparticles were prepared and embedded into the Combi-CLEAs to produce the magnetic Combi-CLEAs in this work. The process for magnetic Combi-CLEAs preparation was optimized, and its properties were investigated. The optimum temperature, thermal stability and optimum pH of magnetic Combi-CLEAs were similar to those of Combi-CLEAs. The catalytic performance of magnetic Combi-CLEAs was tested with the biosynthesis of ( S )-ethyl 4-chloro-3-hydroxybutyrate (( S )-CHBE). Magnetic Combi-CLEAs could tolerate higher substrate concentration in the biphasic system. The catalytic efficiency and long-term operational stability of magnetic Combi-CLEAs were obviously superior to those of Combi-CLEAs in both aqueous and biphasic systems. Embedding of magnetic Fe 3 O 4 nanoparticles endowing rigidity contributed to these improvements. Furthermore, the preparation of magnetic Combi-CLEAs was easy, and its recovery during multiple batches of reactions could be fulfilled by magnetic field. Aforementioned advantages make the magnetic Combi-CLEAs hold obvious potential for industrial application. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs)-based ultrasonic extraction of terpene trilactones (TTLs) fromGinkgo bilobaleaves was efficiently developed. Sixteen DESs were prepared, and DESs composed of choline chloride-urea (ChCl-U) and betaine-ethylene glycol (BE-EG) gave higher TTL extraction yields than the present, most efficient solvent 70% ethanol. The extraction conditions were further optimized, and the optimum conditions were as follows: taking BE-EG containing 40% (w/w) water as the extraction solvent, 1:10 ofG. bilobaleaves powder-to-solvent ratio, and ultrasonic treatment at 45°C and 100 W for 20 min. A total extraction yield of 1.94 ± 0.03 mg/g was obtained under the optimum conditions, which indicated that 99.37% of TTLs could be extracted from theG. bilobaleaves powder by a single extraction. Moreover, the polyamide resin was used to recover the TTLs in DES extracting solution, and recovery yield of 95.1% was attained. Therefore, BE-EG containing 40% (w/w) water was a potential alternative solvent for TTLs extraction fromG. bilobaleaves. [ABSTRACT FROM AUTHOR]

Nitrilase from Arthrobacter aurescens CYC705 can hydrolyze the iminodiacetonitrile to iminodiacetic acid (IDA) efficiently, and its high-level production in Escherichia coli has not been established. In the present work, the production of this nitrilase expressed in E. coli BL21(DE3) with a recombinant plasmid pET28a-cyc705 was optimized. Various culture conditions and process parameters including medium components and concentrations, inducer types and concentrations, inducing temperature and time were systematically examined in a shake flask. After optimization, the OD600, nitrilase activity, and productivity were obviously improved and achieved to 40.91 ± 1.341, 98.12 ± 1.248 U/mL, and 2,230 ± 28.36 U L−1 H−1, respectively, about 2.1-, 30-, and 33-fold increases as compared with those in the primary medium. Furthermore, four different fermentation strategies were adopted to scale up cultivation of the recombinant E. coli BL21(DE3)/pET28a-cyc705 in a 3.7-L fermenter. Substituting the peanut powder with fish peptone and accompanying with 1.0% glycerol feeding could significantly reduce the bubble production and shorten the fermentation time, which resulted in a nitrilase productivity of 4,653 ± 38.16 U L−1 H−1 that was about two times higher than that in a shake flask. The high-level production of A. aurescens CYC705 nitrilase established in this study will meet the need of industrial biosynthesis of IDA. [ABSTRACT FROM AUTHOR]

Semi-synthetic β-lactam antibiotics (SSBAs) are one of the most important antibiotic families in the world market. Their enzymatic synthesis can be catalyzed by penicillin G acylases (PGAs). In this study, to improve enzymatic synthesis of ampicillin, site-saturating mutagenesis was performed on three conserved amino acid residues: βF24, αR146, and αF147 of thermo-stable penicillin G acylase from Alcaligenes faecalis (Af PGA). Four mutants βF24G, βF24A, βF24S, and βF24P were recovered by screening the mutant bank. Kinetic analysis of them showed up to 800-fold increased k cat / K m value for activated acyl donor D-phenylglycine methyl ester (D-PGME). When βF24G was used for ampicillin synthesis under kinetic control at industrially relevant conditions, 95% of nucleophile 6-aminopenicillanic acid (6-APA) was converted to ampicillin in aqueous medium at room temperature while 12% process time is needed to reach maximum product accumulation at 25% enzyme concentration compared with the wild-type Af PGA. Consequently, process productivity of enzymatic synthesis of ampicillin catalyzed by Af PGA was improved by more than 130 times, which indicated an enzyme viable for efficient SSBAs synthesis. [ABSTRACT FROM AUTHOR]

Serratia marcescens lipase ( Sm L) is an important biocatalyst used to enantioselectively hydrolyze (±)- trans-3-(4-methoxyphynyl) glycidic acid methyl ester. However, the economically justified level recombinant soluble expression of Sm L in Escherichia coli has not been established. Thus, fusion genes of lipase from S. marcescens H30 with different fusion tags were constructed and expressed in E. coli. The effects of fusion tags were revealed. A significant increase in recombinant lipase solubility showed that E. coli BL21 ( DE3)/p ET32a- Sm L was a suitable choice for Sm L production. To optimize the performance of recombinant Sm L production, changes in culture medium compositions and induction conditions were systematically tested. Finally, the recombinant Sm L activity and productivity reached approximately 23,000 U/L and 1,278 U/L/H in shake flasks, respectively. This value is the highest Sm L activity attained by heterogeneous recombinant expression in E. coli. Lipase activity and productivity reached 19,650 U/L and 1,228 U/L/H, respectively, by scaling up Sm L production in a 7.0 L fermenter. The existence of the Trx tag did not influence the chiral selectivity of recombinant Sm L. These findings indicate a possibility for soluble and economical Sm L expression in E. coli to meet industrial needs. [ABSTRACT FROM AUTHOR]

Lodderomyces elongisporus LH703 isolated from soil samples contained three novel aldo–keto reductases (AKRs) (LEAKR 48, LEAKR 49, and LEAKR 50). The three enzymes were cloned, expressed, and purified to homogeneity for characterization. These three AKRs shared <40% amino acid identity with each other. LEAKR 50 was identified as a member of AKR3 family, whereas the other two LEAKRs were identified as members of two novel AKR families, respectively. All the three AKRs required nicotinamide adenine dinucleotide phosphate as a cofactor. However, they showed diverse characteristics, including optimum catalyzing conditions, resistance to adverse reaction conditions, and substrate specificity. LEAKR 50 was estimated to be a promising biocatalyst that could reduce ethyl 4-chloroacetoacetate with high enantiomeric excess (98% e. e.) and high activity residue under adverse conditions. [ABSTRACT FROM AUTHOR]

A major obstacle in the commercialization of biodiesel is its cost of manufacturing, primarily the raw material cost. In order to decrease the cost of biodiesel, soapstock oil was investigated as the feedstock for biodiesel production. Because the soapstock oil containing large amounts of free fatty acids (FFAs) cannot be effectively converted to biodiesel, complicated two-stage process (esterification followed by transesterification) was generally adopted. In this study, simple one-stage lipase catalyzed methanolysis of soapstock oil was developed via one-pot esterification and transesterification. Water produced by lipase catalyzed esterification of FFAs affected the lipase catalyzed transesterification of glycerides in the soapstock oil severely. Addition of tert-alcohol could overcome this problem and enhance the fatty acid methyl ester (FAME) yield from 42.8% to 76.4%. The FAME yield was further elevated to 95.2% by optimizing the methanol/oil molar ratio, lipase amount, and water absorbent. The developed process enables the simple, efficient, and green production of biodiesel from soapstock oil, providing with a potential industrial application. [ABSTRACT FROM AUTHOR]

Production of biodiesel, a mixture of alkyl esters of fatty acids, by a lipase-catalyzed irreversible transesterification of Pistacia chinensis Bunge seed oil using dialkyl carbonate as an acyl acceptor is studied. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize five important reaction variables. A quadratic model was established to modify those variables for high biodiesel yield. From the analysis of variance (ANOVA), the most important variables in the experimental design response were the reaction time, temperature, the molar ratio of oil to diethyl carbonate, and the amount of water added. The biodiesel yield predicted by the model was 98.2% under the optimal conditions and the subsequent verification experiments gave the average biodiesel yield of 97.6% thus confirming the validity of the predicted model. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a nitrilase-CLEA mediated dynamic kinetic resolution for the asymmetric synthesis of d-N-formyl-phenylglycine was developed. Cross-linked enzyme aggregates (CLEAs) of nitrilase from Sphingomonas wittichii RW1 were first prepared and characterized. Compared with the free nitrilase, nitrilase-CLEAs showed higher stability against various conditions such as pH and temperature. The nitrilase-CLEA catalyzed dynamic kinetic resolution of N-formyl-phenylglycinonitrile was further optimized. Under the optimal conditions, the yield and ee value of N-d-formyl-phenylglycine achieved 95% and 97%, respectively. Additionally, the nitrilase-CLEAs could be repeatedly used in the batch biotransformation, and the activity retained more than 70% of the initial activity after 6 batches. These results indicated that the nitrilase-CLEA mediated dynamic kinetic resolution was a promising method for the synthesis of d-N-formyl-phenylglycine. [Copyright &y& Elsevier]

Abstract: A strategy of nitrilase mediated dynamic kinetic resolution toward the synthesis of d-phenylglycine was developed, using aqueous-1-octanol biphasic system. Due to the efficient suppression of the decomposition of phenylglycinonitrile, a maximum yield of 81% is obtained. This result indicates that the nitrilase mediated dynamic kinetic resolution is a promising method toward the synthesis of d-phenylglycine and its derivatives. [Copyright &y& Elsevier]

Highlights: [•] The solubility of GLA expression in E. coli was significantly affected by expression system. [•] Lactose used as inducer and lower inducing temperature could reduce the GLA inclusion formation. [•] Dextrin used as carbon source could promote the accumulation of soluble GLA in E. coli. [•] High-level expression of NK703 GLA was obtained with a synthetic medium and a feeding medium. [ABSTRACT FROM AUTHOR]

Abstract: A new strategy based on enantioselective acylation properties of relatively unknown penicillin G acylase from Alcaligenes faecalis has been developed for the production of pharmacologically interesting enantiomerically pure d-phenylalanine. In order to get high reaction rate and enantioselectivity, two key factors (pH and temperature) and eight different acyl donors were optimized, and the optimal acylation reaction was carried out at pH 10, 35°C, using phenylacetamide as the acyl donor. This enantioselective acylating method is also illustrated by the effective production of five different p-substituted phenylalanine derivatives in enantiopure. [Copyright &y& Elsevier]

Abstract: An efficient approach to synthesize terpene esters using plant lipase-Carica papaya lipase (CPL) as the biocatalyst was developed in this work. The effects of chain length of acyl donor and solvent type on the CPL-catalyzed transesterification reaction were investigated firstly. It was found that CPL showed the highest activity in n-hexane with vinyl octanoate as the best acyl donor. To obtain high yield of terpene esters, the main reaction parameters were studied and further optimized by response surface methodology. Ping–Pong Bi–Bi mechanism with dead end complex of citronellol was found to fit the initial rate data and the kinetic parameters were obtained by regression analysis. The optimal conditions were: 55°C, 9% (w/w) of CPL based on substrate, equimolar ratio of substrates. Under these conditions, yield of more than 99% was achieved after 8h reaction. Ionic liquids (ILs) were used to improve the operational stability because the CPL was found to lose its activity markedly during the repeated runs, it showed that the stability of CPL increased about 5 times when it was coated with ionic liquids. The CPL is low cost yet effective, thus the process developed here shows obvious potential for the production of terpene esters industrially. [Copyright &y& Elsevier]

Abstract: Dimethyl/diethyl carbonate was adopted as extraction solvent and transesterification reagent at the same time for in situ lipase-catalyzed reactive extraction of oilseeds for biodiesel production in this work. Fatty acid methyl esters and ethyl esters were respectively obtained with higher yields than those achieved by conventional two-step extraction/transesterification. The augment ranged from 15.7% to 31.7%. The key parameters such as solvent/seed ratio and water content were further investigated to find their effects on the in situ reactive extraction. The highest yields of Pistacia chinensis Bunge methyl ester, P. chinensis Bunge ethyl ester, Jatropha curcas L methyl ester and J. curcas L ethyl ester could attain 89.6%, 90.7%, 95.9% and 94.5%, respectively under the optimized conditions. [Copyright &y& Elsevier]

Abstract: A lipase-producing bacterium K107 was isolated from soil samples of China and identified to be a strain of Proteus sp. With genome-walking method, the open reading frame of lipase gene lipK107, encoding 287 amino acids, was cloned and expressed in a heterologous host, Escherichia coli BL21 (DE3). The recombinant lipase was purified and characterized, and the optimum pH of the purified LipK107 was 9, at 35°C. The recombinant E. coli expressing lipK107 was applied in biodiesel production in the form of whole-cell biocatalyst. Activity of the biocatalyst increased significantly when cells were permeabilized with 0.3% (w/v) cetyl-trimethylammoniumbromide (CTAB). This transesterification was carried out efficiently in a mixture containing 5M equivalents of methanol to the oil and 100% water by weight of the substrate. It was the first time to use E. coli whole-cell biocatalyst expressing lipase in biodiesel production, and the biodiesel reached a yield of nearly 100% after 12h reaction at the optimal temperature of 15°C, which was the lowest temperature among all the known catalyst in biodiesel production. [Copyright &y& Elsevier]

Abstract: A solvent engineering strategy was applied to the lipase-catalyzed methanolysis of triacylglycerols for biodiesel production. The effect of different pure organic solvents and co-solvent mixtures on the methanolysis was compared. The substrate conversions in the co-solvent mixtures were all higher than those of the corresponding pure organic solvents. Further study showed that addition of co-solvent decreased the values of |log P interface −log P substrate| and thus led to a faster reaction. The more the values of |log P interface −log P substrate| decreased, the faster the reaction proceeded and the higher the conversion attained. Different co-solvent ratio was further investigated. The co-solvent mixture of 25% t-pentanol:75% isooctane (v/v) was optimal, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. There was no obvious loss in lipase activity even after being repeatedly used for 60 cycles (720h) with this co-solvent mixture as reaction medium. Other lipases and lipase combinations can also catalyze methanolysis in this co-solvent mixture. Furthermore, other vegetable oils were also explored for biodiesel production in this co-solvent mixture and it had been found that this co-solvent mixture media has extensive applicability. [Copyright &y& Elsevier]

To achieve sustainable development goals, the exploitation of green solvents has been a research hotspot. Owing to the easier preparation process with 100% atom economy, low cost, potential biodegradability and negligible toxicity, deep eutectic solvents (DESs) are recognized as attractive substitutes of organic solvents and ionic liquids. However, the most synthesized DESs are miscible with aqueous media as well as hydrophilic organic solvents, which strictly restrict their applications in water-containing or lipophilic samples. Very recently, hydrophobic DESs (HDESs) have been discovered with hydrophobicity and good solvation abilities for organic and inorganic compounds. The emergence of HDESs overcomes the limitations of traditional hydrophilic DESs and extends the application scopes. In this review, recent progress on the properties and applications of HDESs in detection technologies for food safety and environment protection, separation and extraction processes, biocatalysis, energy utilization, enantioseparation, material modification and pharmaceutical fields since 2015 was reported. The contributions of HDESs lie in broadening the application scopes of DESs and alleviating some of the current industrial and social issues. A brief outlook on the future perspectives and unsolved challenges is also proposed. The aim of this review is to inspire the research enthusiasm to HDESs and promote the industrial development of HDESs. [Display omitted] [ABSTRACT FROM AUTHOR]

BACKGROUND: The increasing demand for sustainable alternatives to traditional protein sources, driven by population growth, underscores the importance of protein in a healthy diet. Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts are currently underutilized as plant‐based proteins but hold great potential in the food industry. However, there is insufficient information available on pecan protein, particularly its protein fractions. This study aimed to explore the physicochemical and functional properties of protein isolate and the main protein fraction glutelin extracted from pecan nuts. RESULTS: The results revealed that glutelin (820.67 ± 69.42 g kg−1) had a higher crude protein content compared to the protein isolate (618.43 ± 27.35 g kg−1), while both proteins exhibited amino acid profiles sufficient for adult requirements. The isoelectric points of protein isolate and glutelin were determined to be pH 4.0 and pH 5.0, respectively. The denaturation temperature of the protein isolate (90.23 °C) was higher than that of glutelin (87.43 °C), indicating a more organized and stable conformation. This is further supported by the fact that the protein isolate had a more stable main secondary structure than glutelin. Both proteins demonstrated improved solubility, emulsifying, and foaming properties at pH levels deviating from their isoelectric points in U‐shaped curves. Compared to the protein isolate, glutelin displayed superior water and oil absorption capacity along with enhanced gelling ability. CONCLUSION: The protein isolate and glutelin from pecan nuts exhibited improved stability and competitive functional properties, respectively. The appropriate utilization of these two proteins will support their potential as natural ingredients in various food systems. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Insufficient biosynthesis efficiency during the lipogenic phase can be a major obstacle to engineering oleaginous yeasts to overproduce very long-chain fatty acids (VLCFAs). Taking nervonic acid (NA, C24:1) as an example, we overcame the bottleneck to overproduce NA in an engineered Rhodosporidium toruloides by improving the biosynthesis of VLCFAs during the lipogenic phase. First, evaluating the catalytic preferences of three plant-derived ketoacyl-CoA synthases (KCSs) rationally guided reconstructing an efficient NA biosynthetic pathway in R. toruloides. More importantly, a genome-wide transcriptional analysis endowed clues to strengthen the fatty acid elongation (FAE) module and identify/use lipogenic phase-activated promoter, collectively addressing the stagnation of NA accumulation during the lipogenic phase. The best-designed strain exhibited a high NA content (as the major component in total fatty acid [TFA], 46.3%) and produced a titer of 44.2 g/L in a 5 L bioreactor. The strategy developed here provides an engineering framework to establish the microbial process of producing valuable VLCFAs in oleaginous yeasts. • A microbial platform was established for high-level production of nervonic acid in Rhodosporidium toruloides. • The genes involved in fatty acid elongation module were overexpressed for promoting VLCFAs biosynthesis during the lipogenic phase. • A lipogenic phase-activated promoter was identified by analyzing the genome-wide transcriptomic data to drive the overexpression of the critical genes. • The engineered strain could continuously produce nervonic acid as a major product of the total fatty acid. • The fermentation medium and process for nervonic acid production in the engineered strain were optimized in the bioreactor. [ABSTRACT FROM AUTHOR]

The nitrilase mediated enantioselective hydrolysis is combined with an in situ racemization. [ABSTRACT FROM AUTHOR]

Herein, we reported that Rhodobacter sphaeroides ( R. sphaeroides ) can be engineered by heterologous expression of an alcohol dehydrogenase ( adh ) from Leifsonia sp. to build a light-driven cofactor regeneration system for synthesis of chiral alcohol. The model substrate, 3′-chloroacetophenone, can be reduced by the engineered R. sphaeroides to ( R )-1-(3-chlorophenyl) ethanol with an enantiomeric excess (e.e.) value of more than 99% in an n -hexane/aqueous biphasic media. This system, which is fully controlled by light, exhibited potential power to be an alternative cofactor regeneration platform for cheap synthesis of various chiral alcohols via the cloning other oxidoreductases with diverse characteristics. [ABSTRACT FROM AUTHOR]

There are some differences in the anti-inflammatory activities of four typical components in EGB (extracts of ginkgo biloba leaves), and there is also a synergistic relationship. The order of inhibiting the NO-release ability of single functional components is OA > GF > OPC > G. Ginkgolide (G), proanthocyanidins (OPC), and organic acids (OA) all have synergistic effects on ginkgo flavonoids (GF). GF:OA (1:9) is the lowest interaction index among all complexes, showing the strongest synergy. The anti-inflammatory mechanism of the compound affects the expression of p-JNK, p-P38, and p-ERK1/2 proteins by inhibiting the expression of iNOS and COX2 genes on NFKB and MAPK pathways. This also provides a research basis for the development of anti-inflammatory deep-processing products of EGB. [ABSTRACT FROM AUTHOR]

The adverse environmental impact and health concerns associated with animal protein production have contributed to the increasing popularity of sustainable alternative proteins. Green leaf biomass represents one of the largest underutilized sources of plant-based protein globally. In this study, we extracted the protein concentrate and major protein fraction glutelin from edible dock (Rumexpatientia L. ×Rumextianshanicus A. Los), a green leaf plant with promising prospects as an excellent source of food protein, to investigate their physicochemical and functional properties. Results showed that both protein concentrate (51.97 ± 3.08%, w/w) and glutelin (50.81 ± 1.30%, w/w) had similar protein contents, shared an isoelectric point of pH 3.0, and contained a well-balanced profile of amino acids. The protein concentrate had a higher denaturation temperature (104.10 °C) than glutelin (97.30 °C), but a poorer gelling ability. However, both proteins exhibited a predominant β-sheet secondary structure. The protein concentrate and glutelin exhibited distinct advantages in terms of water and oil absorption capacity, respectively. The emulsifying and foaming abilities of the two proteins exhibited a consistent trend with protein solubility, resembling U-shaped curves in a pH-dependent variation pattern. Additionally, alkaline and acidic conditions favored preferred emulsifying stability and foaming stability, respectively. The desirable properties of edible dock shed light on its immense potential as a novel alternative source of plant proteins, positioning it as a highly promising candidate for utilization as a nutritious functional ingredient within the food industry. [Display omitted] • Edible dock is an herbaceous plant with a higher protein content than common plants. • Glutelin had the highest proportion among the protein fractions in the edible dock. • Edible dock proteins were high in essential amino acids for adult consumption. • Edible dock proteins had a stable structure due to the highest proportion of β-sheet. • Edible dock proteins had good protein solubility in neutral environments. [ABSTRACT FROM AUTHOR]

Ginkgo seeds are rich in nutrients and bioactive compounds, but they cause poisoning after excessive consumption, thus limiting their application. In this work, enzymatic degradation technology was employed to remove ginkgotoxins presented in ginkgo seeds, including 4'-O-methylpyridoxine (MPN) and MPN-5'-glucoside (MPNG). Through the screening of four oxidases and ten reaction mediators, the laccase-syringaldehyde system was successfully established. After optimizing the reaction conditions using response surface methodology (RSM), ginkgotoxins in both raw and boiled ginkgo seed powder was completely degraded at a temperature of 40 °C and a solvent to solid ratio (60 mL/g) of the ginkgo seed powder suspension within 3 h. Furthermore, the main nutritional components of detoxified ginkgo seed powder did not exhibit significant changes, but there was inevitably a decrease in the content of bioactive compounds. Finally, an acute oral toxicity assessment demonstrated that the detoxified ginkgo seed powder was virtually non-toxic. Therefore, enzymatic degradation using the laccase-syringaldehyde system has the potential to be a simple and effective approach for removing ginkgotoxins from ginkgo seed powder, thereby meeting the safety requirements for ginkgo products. [Display omitted] • A laccase-syringaldehyde system was established to degrade ginkgotoxins. • Both MPNG and MPN were completely degraded under the optimal enzymatic degradation conditions. • All ginkgotoxins present in both raw and boiled ginkgo seed powder could be effectively degraded. • Detoxified ginkgo seed powder prepared was proven to be non-toxic by an acute oral toxicity test. • The enzymatic removal technology is simple, efficient and suitable for the industrial use. [ABSTRACT FROM AUTHOR]

This study aimed to screen microorganisms capable of removing ginkgolic acids (GAs) from Ginkgo biloba leaf. Given the presence of long alkyl side chains in GAs, the study first focused on screening microorganisms that could utilize long-chain alkanes (n-tridecane, n-pentadecane, and n-heptadecane) and further studying their GAs degradation abilities. The results showed that the degradation rates of GAs by the two bacteria strains (identified as Pantoea sp.) were about 50 %, and the degradation rates of GAs by the nine fungal strains (identified as Fusarium sp.) were about 95 %. Meanwhile, Lactiplantibacillus plantarum was also found to exhibit a robust capacity for degrading GAs. Through further optimization of the medium components and fermentation conditions, Lactiplantibacillus plantarum achieved a degradation rate of 81.581 % for total GAs after 72 hours of cultivation. Notably, this process did not significantly impact flavonoids and terpene lactones present in Ginkgo biloba extract (EGb), which are essential for its therapeutic properties. Additionally, the results demonstrated that the hydrophobicity of GAs significantly influenced the degradation efficiency of GAs by Lactiplantibacillus plantarum. This study highlights the potential industrial application value of Lactiplantibacillus plantarum in the production of ginkgo products with low GAs content, thereby enhancing the safety and efficacy of this widely used medicinal plant. • Two strains of bacteria and nine strains of fungi screened from the soil could degrade GAs. • Lactiplantibacillus plantarum commonly used in food industry has good ability to degrade GAs. • Lactiplantibacillus plantarum has no significant effect on flavonoids and other active ingredients in EGb. • The structure of GAs had great influence on the degradation effect of GAs by Lactiplantibacillus plantarum. [ABSTRACT FROM AUTHOR]

Ginkgo biloba L. seeds are used for food and medicinal purposes in China, but excessive consumption of them can cause acute toxicity. Ginkgotoxin (MPN) and its-5'-glucoside (MPNG) are the main toxic substances in ginkgo seeds. Ginkgo biloba L. trees are widely cultivated in China, and there are fewer studies on total ginkgotoxin (TMPN, MPN and MPNG) in ginkgo from different regions, which is the main motivation for this work. We determined the levels of TMPN in ginkgo seed samples from different regions of China (24.44–41.19 °N, 98.68–124.43 °E), which ranged from 140.96 ± 4.19 μg/g to 537.14 ± 10.78 μg/g. We found that all 131 ginkgo seed samples contained TMPN. Pearson's correlation was performed to analyze the correlation between the TMPN, tree age, geographical location, and climatic factors. The study showed that for geographical factors, longitude was significantly positively correlated with TMPN, and altitude was significantly negatively correlated with TMPN. Regarding climatic factors, mean annual temperature (MAT) and mean warmest month temperature (MWMT) were significantly and positively correlated with TMPN. Our results contribute to a better understanding of the distribution of TMPN in ginkgo seeds in China and lay a scientific foundation for improving low toxicity and safe ginkgo food ingredients. [Display omitted] • Each Ginkgo biloba seed sample contained a certain amount of total ginkgotoxin (TMPN). • Longitude was significantly and positively correlated with TMPN. • Altitude was significantly and negatively correlated with TMPN. • The mean annual temperature and the mean warmest month temperature were both significantly and positively correlated with TMPN. [ABSTRACT FROM AUTHOR]

From an environmental perspective, utilizing nonconventional solvents (i.e. green solvents) with low ecological footprints is a highly beneficial alternative to using conventional organic solvents to form a reaction system. The nitrile hydratase (NHase, EC 4.2.1.84) catalyzed hydration of 2-amino-2,3-dimethylbutyronitrile (ADBN) to 2-amino-2,3-dimethylbutyramide (ADBA) in various green solvent–aqueous reaction systems was investigated in this study. After systematically optimizing the reaction conditions, the HFE-7100/H2O (v/v, 10%) biphasic system was ultimately identified as a promising reaction system for reducing product inhibition, avoiding substrate hydrolysis, and facilitating product separation and solvent recovery. The average ADBA yield of an entire batch reaction was 97.3%, which is obviously higher than those obtained with previously reported chemical or enzymatic methods. This is the first attempt to apply a fluorous solvent–aqueous biphasic system to a biocatalytic process, and the results suggest that the fluorous solvent employed in the biphasic system satisfies the requirements for green chemistry. [ABSTRACT FROM AUTHOR]

The three-enzyme three-pot using immobilized d -amino acid oxidase (DAAO), glutaryl-7-ACA acylase (GLA), and cephalosporin C deacetylase (CAH) was the main strategy for industrial conversion of cephalosporin C (CPC) to deacetyl-7-aminocephalosporanic acid (D-7-ACA), a key pharmaceutical intermediate that is used for the production of 3-vinyl substituted β-lactams antibiotics. In order to simplify this traditional process, we developed an one-pot bi-enzyme catalyzed procedure by coupling immobilized cephalosporin C acylase (CPCA) with immobilized cephalosporin C deacetylase (CAH), which contained two parallel cascade reactions: firstly, hydrolysis of CPC to 7-ACA by CPCA, then deacetylation of 7-ACA to D-7-ACA by CAH (route 1); or firstly, hydrolysis of CPC to deacetyl-CPC (D-CPC) by CAH, then de-α-aminoadipoylation of D-CPC to D-7-ACA by CPCA (route 2). A D-7-ACA yield of 78.39% was achieved in 30 min in a single reactor under the optimized enzyme amount. The specific productivity of D-7-ACA reached 10.85 g g −1 h −1 L −1 , which increased approximately 4-fold compared to that obtained from the two-pot enzymatic process. The half-time of immobilized CPCA was approximately 18 h while immobilized CAH was approximately 534 h under the operational conditions. These results demonstrated the industrial feasibility of this one-pot process and its clear advantages towards the traditional three-enzyme three-pot process. [ABSTRACT FROM AUTHOR]

Summary: The hypolipidemic effect of soymilk fermented by Lactiplantibacillus plantarum X7021, which is a novel strain isolated from the brine of stinky tofu, on high‐fat‐diet (HFD)‐induced hyperlipidemic mice was studied. The fermented soymilk could significantly inhibit 3‐hydroxy‐3‐methyl glutaryl coenzyme A reductase (HMGR) in vitro, and lower 23.8% total cholesterol, 45.5% triglyceride, and 15.4% low density lipoprotein cholesterol and increase 31.1% high density lipoprotein cholesterol in hyperlipidemic mice serum at the end of 4 w administration period. At the same time, the oxidative stress in hyperlipidemic mice was nearly alleviated to normal level. Furthermore, the bile salt hydrolase produced by the strain, the key enzymes, hormones and transcriptional regulators involved in hepatic lipids metabolism, faecal short chain fatty acids contents, and the abundance and diversity of gut microbiota in hyperlipidemic mice were analysed, verifying that the fermented soymilk ameliorated hyperlipidemia through the degradation of bile salts, modulating lipids metabolism and influencing gut microbiota. Consequently, this fermented soymilk is prospective in the functional food for the hypolipidemic application. [ABSTRACT FROM AUTHOR]

Hypsizygus marmoreus is a representative edible mushroom with low-temperature fruiting after a long postripening (LFLP). Clarifying the mechanism of LFLP and applying a rigorous low-temperature-limited process will optimize the mushroom cultivation process. This study performed an integrative multi-omics analysis of the molecular mechanism of LFLP in combination with genetic, physiological, and cultivation confirmation. The results showed that the amino acid content was increased during LFLP, mainly arginine. pH analysis showed acidification in the postripening stage and alkalization in the substrates of the reproductive growth stage. An enzyme activity test confirmed the increased enzyme activity of arginase and citrate synthase in the postripening stage. Weighted gene coexpression network analysis of the transcriptome and metabolomics indicated that pH variation is correlated mainly with changes in citrate and arginine. Multi-omics reveals a straightforward way of providing enriched materials for amino acid biosynthesis, namely, synergistically elevating citric acid and arginine through enhanced activity of the arginine synthesis branch pathway in the citrate cycle. Our study confirmed that GCN2 mediated metabolic adaptation by enhancing protein translation, highlighting its regulatory role during LFLP. Exogenously added citric acid and arginine shortened the postripening period by 10 days and increased the fruiting body yield by 10.2~15.5%. This research sheds light on the molecular mechanism of LFLP in H. marmoreus and highlights the promising application of nutrient accumulation in high-efficiency cultivation. [ABSTRACT FROM AUTHOR]

The cultivation of edible mushrooms is increasing because of their widely recognized nutritional benefits. Advancements in cultivation techniques have facilitated large-scale mushroom production, meeting the growing consumer demand. This rise in cultivation has led to an increasingly urgent demand for advanced postharvest preservation methods to extend the shelf life of these mushrooms. The postharvest preservation of fresh edible mushrooms involves complex physiological changes and metabolic activities closely associated with gas composition, microbial presence, moisture content, ambient temperature, and enzymatic activity. Preserving edible mushrooms through various preservation strategies (physical, chemical, biological, and nanopackaging approaches) relies on regulating postharvest factors. Nanopackaging can preserve mushrooms' sensory and nutritional qualities due to the specific characteristics of nanomaterials, such as antimicrobial properties and gas/moisture barriers. Furthermore, the review explores current trends, fundamental mechanisms, and upcoming challenges in utilizing nanomaterials, particularly their capacity to enhance the "cell wall" integrity of edible mushrooms by regulating postharvest factors. • Mushroom-specific preservation strategies is needed urgently in edible mushrooms preservation. • The impact of the postharvest factors on edible mushroom preservation methods is detailed. • The underlying mechanisms of nanopackaging on edible mushroom preservation are discussed. • Nanocomposite material application presents a promising strategy for edible mushroom preservation. [ABSTRACT FROM AUTHOR]

• Tyrosinase and β-glucosidase were the most strongly associated enzymes. • Chilling stress induced abnormal up-regulation of β-glucosidase and tyrosinase. • Cryogenic autolysis was alleviated by inhibitors of β-glucosidase and tyrosinase. • D-Glucono-1,5-lactone prevented autolysis at 4 °C. Cryogenic autolysis of Volvariella volvacea restricts the postharvest storage and sale of this commercially cultivated mushroom. Previous studies have shown that the specific ubiquitin-binding enzyme E2 (UBEV2) inhibitor (L345-0044) is an effective agent to prevent cryogenic autolysis. The safety of L345-0044 as a food preservative is debatable. Thus, it is essential to find a safer food additive for the preservation of V. volvacea. In this study, absolute quantitative transcriptome and metabolome analyses were performed to analyze the gene and metabolite expression profiles of the fruiting bodies treated with L345-0044 at 4 °C. Correlative pathway analysis of the associated metabolites from the correlation analysis of differentially expressed metabolites and genes (> 3) screened out the pathways of tyrosine metabolism and carbon metabolism (Impact > 1) in which tyrosinase and β-glucosidase were the two most strongly associated enzymes. qPCR confirmed that chilling stress (CS) induced abnormal up-regulation of β-glucosidase (BGVV1) and tyrosinase. Western blot and enzyme activity assays further confirmed our results that CS-induced cryogenic autolysis could be alleviated by inhibitors of β-glucosidase and tyrosinase. The activities of β-glucosidase and tyrosinase were increased by 23.34 % and by 250.34 %, respectively, after CS treatment for 24 h but were reduced by 27.25 % and by 73.20 %, respectively, after treatment with inhibitors that included conduritol B epoxide and arbutin, respectively. Among the inhibitors, D-Glucono-1,5-lactone prevented autolysis at 4 °C for more than 24 h. As a safe conventional food additive, its excellent performance in preventing autolysis indicates that it has a very promising application in the postharvest management of V. volvacea. [ABSTRACT FROM AUTHOR]

Camellia oleifera seed oil is rich in unsaturated fatty acids, and has various nutraceutical and health benefits, but the application of it is hindered by inappropriate processing methods. In this work, we developed an efficient procedure for preparing high quality Camellia oleifera seed oil using enzymatic extraction and demulsification. Through the screening of enzyme types, acid protease was found to be the optimal enzyme for extraction, resulting in a clear oil yield of 66.94±0.70% under the optimized conditions determined by using response surface methodology (RSM). In order to address the issue of excessive emulsion formation during enzymatic extraction, enzymatic demulsification was utilized to recover the clear oil from the emulsion layer. After successively addition of medium temperature α-amylase and acid protease under the optimized conditions, a demulsification rate of up to 74.31±0.27% and a clear oil yield of 16.01% were obtained. Therefore, a total clear oil yield of 82.95% was achieved. Finally, the quality indexes of three clear oil samples were analyzed, and all of them attained level one of Chinese National Standard GB/T 11765–2018. These results demonstrate the efficient preparation of high-quality Camellia oleifera seed oil by full enzymatic extraction and demulsification. It provides valuable theoretical guidance for the environmentally friendly extraction of Camellia oleifera seed oil, with potential applications in its production. [Display omitted] • A two-step enzymatic method was established to produce Camellia oleifera seed oil. • The oil in the emulsion layer was recovered through enzymatic demulsification. • The enzymatic extraction and demulsification achieved a clear oil yield of 82.95%. • The clear oil obtained in this work met the level one standards of GB/T 11765–2018. • The procedure in this work is simple, cost-effective, and environmentally friendly. [ABSTRACT FROM AUTHOR]

An efficient synthesis of the ( S)-3-amino-3-phenylpropanoic acid enantiomer has been achieved by Carica papaya lipase (CPL) catalysed enantioselective alcoholysis of the corresponding racemic N-protected 2,2,2-trifluoroethyl esters in an organic solvent. A high enantioselectivity ( E > 200) was achieved by two strategies that involved engineering of the substrates and optimization of the reaction conditions. Based on the resolution of a series of amino acids, it was found that the structure of the substrate has a profound effect on the CPL-catalysed resolution. The enantioselectivity and reaction rate were significantly enhanced by switching the conventional methyl ester to an activated trifluoroethyl ester. When considering steric effects, the substituted phenyl and amino groups should not both be large for the CPL-catalysed resolution. The mechanism of the CPL-catalysed enantioselective alcoholoysis of the amino acids is discussed to delineate the substrate requirements for CPL-catalysed resolution. Finally, the reaction was scaled up, and the products were separated and obtained in good yields (≥ 80 %). The ( S)-3-amino-3-phenylpropanoic acid obtained was used as a key chiral intermediate in the synthesis of ( S)-dapoxetine with very high enantiomeric excess (> 99 %). [ABSTRACT FROM AUTHOR]

Background: Microbial lipases particularly Pseudomonas lipases are widely used for biotechnological applications. It is a meaningful work to design experiments to obtain high-level active lipase. There is a limiting factor for functional overexpression of the Pseudomonas lipase that a chaperone is necessary for effective folding. As previously reported, several methods had been used to resolve the problem. In this work, the lipase (LipA) and its chaperone (LipB) from a screened strain named AB which belongs to Pseudomonas aeruginosa were overexpressed in E. coli with two dual expression plasmid systems to enhance the production of the active lipase LipA without in vitro refolding process. Results: In this work, we screened a lipase-produced strain named AB through the screening procedure, which wasidentified as P. aeruginosa on the basis of 16S rDNA. Genomic DNA obtained from the strain was used to isolate the gene lipA (936 bp) and lipase specific foldase gene lipB (1023 bp). One single expression plasmid system E. coli BL21/pET28a-lipAB and two dual expression plasmid systems E. coli BL21/pETDuet-lipA-lipB and E. coli BL21/pACYCDuet-lipA-lipB were successfully constructed. The lipase activities of the three expression systems were compared to choose the optimal expression method. Under the same cultured condition, the activities of the lipases expressed by E. coli BL21/pET28a-lipAB and E. coli BL21/pETDuet-lipA-lipB were 1300 U/L and 3200 U/L, respectively, while the activity of the lipase expressed by E. coli BL21/pACYCDuet-lipA-lipB was up to 8500 U/L. The lipase LipA had an optimal temperature of 30°C and an optimal pH of 9 with a strong pH tolerance. The active LipA could catalyze the reaction between fatty alcohols and fatty acids to generate fatty acid alkyl esters, which meant that LipA was able to catalyze esterification reaction. The most suitable fatty acid and alcohol substrates for esterification were octylic acid and hexanol, respectively. Conclusions: The effect of different plasmid system on the active LipA expression was significantly different. pACYCDuet-lipA-lipB was more suitable for the expression of active LipA than pET28a-lipAB and pETDuet-lipA-lipB. The LipA showed obvious esterification activity and thus had potential biocatalytic applications. The expression method reported here can give reference for the expression of those enzymes that require chaperones. [ABSTRACT FROM AUTHOR]

Abstract: A facile pretreatment method was developed to obtain high specific activity of PGA from recombinant E. coli cells for preparing immobilized enzyme with high activity, which coupled selective extraction of PGA with butyl acetate and adsorption of butyl acetate with active carbon. Butyl acetate (5%, v/v) led to a 92.0% release of PGA, the specific activity of which in the extracting solution was twice that obtained by sonication. The negative effect on PGA immobilization due to residual butyl acetate in the extracting solution was removed by adding active carbon (8%, w/v). The final PGA solution meets requirement for industrial immobilization while eliminating the high cost of a traditional purification process. This pretreatment method developed in this work is simple, highly performing and cost-effective. It has been employed in a 10tons/year immobilized PGA production line. [Copyright &y& Elsevier]

Abstract: In the context of specifying the origin of enzyme enantioselectivity, the present study explores the lipase enantioselectivity towards secondary alcohols of similar structure from the perspective of substrate binding. By carrying out molecular mechanics minimization as well as molecular dynamics simulation on tetrahedral reaction intermediates which are used as a model of transition state, we identify an unconventional productive binding mode (PBM)—M/H permutation type for Candida antarctica lipase B (CALB). The in silico results also indicate that different PBMs of the slow-reacting enantiomer do exist in one lipase even when there is little structural differences between substrates, e.g. compounds with Ph or CH2CH2Ph group display the M/H permutation type PBM while molecules with CH2Ph show the M/L permutation type PBM. By relating the PBMs of substrates to the experimentally determined E-values obtained by Hoff et al. , we find that disparity in PBM of the slow-reacting enantiomer determines why E-values of substrates with CH2Ph were lower than E-values of substrates with Ph or CH2CH2Ph group. The modeling results also suggest that the “pushed aside” effect of the F atom and Br atom accommodates the medium size substituent of the substrate better in the stereospecificity pocket of the enzyme. [Copyright &y& Elsevier]

Industrial bakers’ yeast strain Saccharomyces cerevisiae LH1 was selected for asymmetric reduction of ethyl benzoylacetate to ( S)-ethyl 3-hydroxy-3-phenylpropionate. Higher reductive efficiency and higher cofactor availability were obtained with the alternation of cultivation condition (mainly growth medium). Compared to the bioreduction by yeast cells grown in malt extract (ME) medium, the concentration of substrate was increased 25-fold (up to 15.6 g/l) in the yeast peptone dextrose (YPD)-grown cells mediated bioreduction with 97.5% of enantioselective excess of ( S)-product. The proteomic responses of S. cerevisiae LH1 cells to growth in aerobic batch cultures fed with either YPD or ME medium were examined and compared. Among the relative quantities of 550 protein spots in each gel, changes were shown in the expression level of 102 intracellular proteins when comparing YPD gel to ME gel. Most of the identified proteins were involved in energy metabolism and several cellular molecular biosynthetic pathway and catabolism. For YPD-grown yeast cells, not only enzymes involved in nicotinamide adenine dinucleotide phosphate regeneration, especially 6-phosphogluconate dehydrogenase, but also alcohol dehydrogenase 1 and d-arabinose 1-dehydrogenase which had been demonstrated activity toward ethyl benzoylacetate to ( S)-hydroxy ester were significantly upregulated. These changes provided us insight in the way the yeast cells adapted to a change in cultivation medium and regulated its catalytic efficiency in the bioreduction. [ABSTRACT FROM AUTHOR]

Abstract: A recombinant Pichia pastoris MutS expressing SAM2 gene of Saccharomyces cerevisiae was cultured for S-adenosylmethionine (SAM) accumulation. Effect of the amount of methanol added (0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 6.0%, 10.0%, and 12.0%) and cell densities (9.57, 13.47, 21.74, 30.90, and 41.24g/L dry cell weight (DCW)) on yield of SAM was found in flask cultivations. In flask experiments, maximal yield of SAM (1.29g/L) was obtained at 2.0% methanol added and 30.90g/L DCW which gave the maximal methanol consumption rate. Conjunct effect of amount of methanol added and cell density was found through Origin 7.0 (7.0 Microcal, USA). Scale up in 3.7L bioreactor, 51% specific yield of SAM was enhanced at 0.6% methanol compared to that of 0.1% methanol. In fed-batches of different cell densities at 0.6% methanol, maximal yield of SAM was 8.66g/L at 100g/L DCW with 64% yield of SAM enhanced again. Methanol consumption rate at 100g/L DCW was 4.81mL/Lh. Maintenance coefficient of 100g/L DCW was lower than that of others significantly, although methanol consumption rate of 90g/L DCW was higher (5.07mL/Lh) than that of 100g/L DCW. [Copyright &y& Elsevier]

[Display omitted] • The role of metabolomics and computers in the study of bitter compounds was comprehensively explored. • The interactions between bitter taste and agonists were critically elaborated. • Systemic strategies for removing or reducing bitter taste were identified. • The direction of future research on bitter substances in food is pointed out. Bitterness is one of the five basic tastes generally considered undesirable. The widespread presence of bitter compounds can negatively affect the palatability of foods. The classification and sensory evaluation of bitter compounds have been the focus in recent research. However, the rigorous identification of bitter tastes and further studies to effectively mask or remove them have not been thoroughly evaluated. The present paper focuses on identification of bitter compounds in foods, structural-based activation of bitter receptors, and strategies to reduce bitter compounds in foods. It also discusses the roles of metabolomics and virtual screening analysis in bitter taste. The identification of bitter compounds has seen greater success through metabolomics with multivariate statistical analysis compared to conventional chromatography, HPLC, LC-MS, and NMR techniques. However, to avoid false positives, sensory recognition should be combined. Bitter perception involves the structural activation of bitter taste receptors (TAS2Rs). Only 25 human TAS2Rs have been identified as responsible for recognizing numerous bitter compounds, showcasing their high structural diversity to bitter agonists. Thus, reducing bitterness can be achieved through several methods. Traditionally, the removal or degradation of bitter substances has been used for debittering, while the masking of bitterness presents a new effective approach to improving food flavor. Future research in food bitterness should focus on identifying unknown bitter compounds in food, elucidating the mechanisms of activation of different receptors, and developing debittering techniques based on the entire food matrix. [ABSTRACT FROM AUTHOR]

BACKGROUND Ginkgo biloba seeds are well known for the significant curative effects on relieving cough and asthma. However, the development of products from ginkgo seeds still falls behind at present, resulting in a great waste of ginkgo seeds' resource. In this work, submerged fermentation of ginkgo seed powder using Eurotium cristatum was studied to investigate its feasibility as a new processing method. RESULTS: To promote the growth of E. cristatum, the optimum fermentation medium was 80.0 g L−1 of ginkgo seed powder with addition of 5.0 g L−1 calcium chloride (CaCl2), 4.0 g L−1 magnesium sulfate (MgSO4), 1.25 g L−1 zinc sulfate (ZnSO4) and 0.65 g L−1 iron(II) sulfate (FeSO4). The optimum fermentation conditions were pH 5.8 ± 0.1, inoculum size 5.1 × 106 CFU mL−1, liquid medium volume 100 mL in 250‐mL Erlenmeyer flask and fermentation 4 days. Through fermentation, the production of lovastatin in fermentation broth could reach up to 32.97 ± 0.17 μg mL−1 and the total antioxidant capacity was improved by more than two‐fold. In addition, 40.15% of the ginkgotoxin in ginkgo seed powder was degraded while the entire degradation of ginkgolic acids was obtained. Moreover, fermented ginkgo seed powder suspension presented pleasant fragrances, and the activities of amylase and protease were enhanced to 11.30 ± 0.10 U mL−1 and 23.01 ± 0.20 U mL−1, respectively. CONCLUSIONS: Submerged fermentation using E. cristatum could significantly enhance the functional value and safety of ginkgo seed powder, and had great potential to become a novel processing method for the development of ginkgo seeds fermented products. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Ginkgotoxin including 4′‐O‐methylpyridoxine (MPN) and MPN‐5′‐glucoside (MPNG) is responsible for Ginkgo seed food poisoning. The purpose of the work reported was to prepare detoxified Ginkgo seed powder and at the same time to retain the nutritional and functional components of Ginkgo seed powder to the maximum extent. RESULTS: Resin adsorption technology was firstly employed to remove ginkgotoxin from water extract of Ginkgo seed powder. Under optimal conditions, the adsorption efficiency of the optimal resin for MPN could reach 100%, and that for MPNG could only reach 85.4 ± 0.93%. Resin adsorption alone could not effectively remove MPN and MPNG simultaneously. Endogenous enzymatic hydrolysis was next attempted to transform MPNG to MPN. MPNG could be completely hydrolyzed to MPN by endogenous enzyme(s) at 40 °C and pH 5.0 in 180 min. Ginkgotoxin only in the form of MPN in the enzymatic hydrolysate was then adsorbed with resin and the conditions were statistically optimized. The adsorption efficiency of MPN reached 98.89 ± 0.99% under the optimized conditions. CONCLUSIONS: Removal of ginkgotoxin by combining endogenous enzymatic hydrolysis with resin adsorption could preserve the main nutritional and functional components of Ginkgo seed powder to the most extent, and did not change its main characteristics. The ginkgotoxin removal method developed in this work is a relatively simple and efficient approach. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Food microbial contamination is a significant contributor to food deterioration, which leads to a shortage of food resources and presents a grand challenge worldwide. While chemical food preservatives provide an effective approach to combat microbiology in food, their overuse and long-term use result in the evolution of bacteria with antibiotic resistance. Fortunately, recent advancements in nanotechnology provide novel opportunities to overcome this obstacle without dependence on antibiotics. Nanozymes have emerged as new tools to combat bacterial infection in the food packaging field, providing an alternative strategy for food preservation. Herein, this comprehensive review summarizes the main antimicrobial mechanisms of nanozymes, and highlights the potential of utilizing nanozymes as a medium for intelligent visualization monitoring of food quality. The forms and challenges of nanozymes for food packaging applications are also discussed, and the proposal for the bio-safety assessment of nanozymes as food packaging is put forth. Furthermore, valuable insights into the future development prospects of nanozymes-based food packaging applications are provided. This review offers an exciting perspective on the application of nanozyme in the food industry and its potential to revolutionize food preservation. [Display omitted] [ABSTRACT FROM AUTHOR]

Ginkgo biloba seeds contain a variety of nutritional and functional components and have high edible and medicinal effects, making them one of the famous food and medicine homologous materials. But G. biloba seeds also contain some harmful ingredients, which have severely restricted the healthy development of the G. biloba seed food industry. Overconsumption of G. biloba seeds can lead to food poisoning. Ginkgotoxin (4′-O-methylpyridoxine, MPN) and ginkgotoxin-5′-glucoside (4′-O-methylpyridoxine-5′-glucoside, MPNG) are the main toxic ingredients of G. biloba seeds and have been studied intensively. This work tries to comprehensively summarize the research status of MPN and MPNG (collectively known as ginkgotoxins), building the scientific basis for further research on ginkgotoxins, with the aspiration to promote the healthy development of the G. biloba seed food industry. In this review, the isolation, identification, extraction, and detection of ginkgotoxins are first introduced. Then, the synthesis and distribution of ginkgotoxins are described and discussed. Finally, the methods used for removing ginkgotoxins and the effects of processing on the ginkgotoxins are analyzed and compared. Reducing ginkgotoxins while preserving the nutritional and functional components of G. biloba seed foods will undoubtedly be a pressing issue in further research. [Display omitted] • Ginkgo biloba seeds contain a variety of nutritional and functional components. • Overconsumption of Ginkgo biloba seeds leads to poisoning. • Ginkgotoxin and ginkgotoxin-5′-glucoside is responsible for Ginkgo biloba seeds poisoning. • MPN and MPNG can be completely removed by some physical and biotechnological methods. • Food processing techniques can only reduce toxicity to a limited extent. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A thermostable glycosidase was cloned and characterized from T. petrophila DSM 13995. • The enzyme is a multi-functional hydrolase with high specificity to arabinofuranosyl. • The enzyme provided the basis for efficient bioconversion of ginsenoside extract. Abstract A thermostable β-xylosidase gene Tpexyl3 from Thermotoga petrophila DSM 13,995 was cloned and overexpressed by Escherichia coli. Recombinant Tpexyl3 was purified, and its molecular weight was approximately 86.7 kDa. Its optimal activity was exhibited at pH 6.0 and 90 °C. It had broad specificity to xylopyranosyl, arabinopyranosyl, arabinofuranosyl and glucopyranosyl moieties. The β-xylosidase activity of the recombinant Tpexyl3 was 6.81 U/mL in the LB medium and 151.4 U/mL in a 7.5 L bio-reactor. It was applied to transform ginsenoside extract into the pharmacologically active minor ginsenoside 20(S)-Rg3, which was combined with thermostable β-glucosidase Tpebgl3. After transforming under optimal condition, the 20 g/L of ginsenoside extract was transformed into 6.28 g/L of Rg3 within 90 min, with a corresponding molar conversion of 95.0% and Rg3 productivity of 1793.49 mg/L/h, respectively. This study is the highest report of a GH3 family glycosidase with arabinopyranosidase activity and also the first report on the high substrate concentration bioconversion of ginsenoside extract to ginsenoside 20(S)-Rg3 by using two thermostable glycosidases. [ABSTRACT FROM AUTHOR]

Highlights • T. litoralis 4-α-glucanotransferase has a strong tendency to form inclusion bodies. • Chaperones and osmolytes enhanced the production of soluble 4-α-glucanotransferase. • Co-expression of molecular chaperones improved enzyme activity 9.5-fold. • Addition of TMAO favored soluble expression of 4-α-glucanotransferase. • This combined optimization strategy increased 4-α-glucanotransferase yield 24.6-fold. Abstract In this study, a combined optimization strategy, based on co-expression of molecular chaperones and supplementation of osmolytes, was used to reduce the formation of inclusion bodies and enhance the expression of the soluble form of 4-α-glucanotransferase. The 4-α-glucanotransferase yield was enhanced by co-expression with pGro7 and supplementation of trimetlylamine oxide. Subsequently, the effects of process conditions (temperature, inducer concentration, and arabinose concentration) on cell growth and 4-α-glucanotransferase production were also investigated in shake flasks. In addition, a modified high-cell-density fermentation approach was proposed and applied in 3-L fermentor supplied with l -arabinose and trimetlylamine oxide, which achieved a dry cell weight of 65.92 g·L−1. Through this cultivation approach at 28 °C, the activity of 4-α-glucanotransferase reached 332.5 U·g−1 dry cell weight, which was 24.6-fold greater than the initial activity in shake flask cultivation. This combined strategy is expected to provide an efficient and economical approach to overproduction of aggregation prone proteins on a large scale. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Low-cost enzyme cocktail with high xylanase activity was produced by A. niger. • Wheat straw was hydrolyzed more effectively than other biomass by the enzyme cocktail. • Xylanase combined with cellulase significantly enhanced the hydrolysis of wheat straw. • Delignification was more efficient than de-hemicellulose for wheat straw hydrolysis. • Crystallinity is little interference with the hydrolysis process of wheat straw. Abstract Based on a general understanding that hemicellulose removal is more efficient than delignification for biomass deconstruction, an Aspergillus niger strain producing high xylanase activity was screened out from seventeen strains by clear halo experiments. Low-cost enzyme cocktail with high xylanase activity was produced from wheat straw medium fermented by the Gyx086 strain. The enzyme cocktail with high xylanase activity could more effectively hydrolyze wheat straw than other biomasses. However, only 30% of total carbohydrates could be hydrolyzed to reducing sugar in untreated wheat straw. Further enzymatic hydrolysis and pretreated trials were carried out, the results indicated that hemicellulose removal was less effective than delignification for de-recalcitrance of wheat straw and the crystallinity is little interference with the hydrolysis process. Delignified wheat straw was near-completely hydrolyzed by the enzyme cocktail in 60 h. This study advanced the knowledge in promoting wheat straw as feedstock for bio-based industry. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A. americana was proved to be a low recalcitrance biomass. • Pectinase was confirmed which dramatically improved saccharification of agave. • Cost-effective enzyme cocktail was produced using wheat straw as substance. • Enzyme cocktail from A. niger Gyx086 can effectively saccharify agave polysaccharide. • Un-pretreated agave biomass was near-completely hydrolyzed at 35 °C in less than 72 h. Abstract To develop a cost-effective, time-saving and efficient saccharification system for converting biomass into mono-/oligo-saccharides for production of bioethanol or other biochemicals, a relatively low recalcitrant and widely available biomass Agave americana was selected as feedstock. During the investigation of efficient enzyme cocktail, pectinase, which usually is neglect for biomass saccharification, was confirmed that it dramatically improves the saccharification of agave biomass. A production-friendly fungal strain of Aspergillus niger Gyx086 was employed for low-cost enzyme cocktails production using wheat straw as substance. The enzyme cocktail which was with hyperactive pectinase activity of 6.29 ± 0.42 U/ml could efficiently saccharify un-pretreated agave biomasses. As a result, under a mild condition at 35 °C in less than 72 h, most of the polysaccharides were completely converted into reducing sugar. The low-cost, process-simplified, and efficient biotechnology should stimulate the development of agave as feedstock for green energy and bio-based products production. [ABSTRACT FROM AUTHOR]

The edible straw mushroom Volvariella volvacea has a desirable taste and diverse effects on health; however, it undergoes rapid autolysis at 4 °C. Spray treatment with the β-glucosidase inhibitor DGlucono-1,5-lactone (DGase) at 100 µmol/L maintained the quality of V. volvacea during storage at 4 °C for 72 h. Enhanced alkaline protease and neutral protease activities can act as indicators of cold stress resistance (CSR) in V. volvacea , as well as the stable ATP level. The total sugar and amino acid content is negatively correlated with CSR in V. volvacea. DGase treatment enhanced the CSR of V. volvacea by inducing the overexpression of genes in the mitochondrial ribosome (mitoribosome). Overexpression of a serine/threonine-protein kinase gene in V. volvacea (VSKM1), which promotes mitoribosome activity in yeast, enhanced freezing tolerance. Our findings indicated that overexpression of VSKM1 promoted CSR by enhancing mitoribosome activity for the quality retention of postharvest V. volvacea. • DGlucono-1,5-lactone spraying maintained the long-term quality of V. volvacea at 4 °C. • Physiological indicators of cold stress resistance were identified in V. volvacea. • The enhanced mitoribosome activity promoted cold stress resistance in V. volvacea. • The overexpression of VSKM1 enhanced mitoribosome activity in V. volvacea. [ABSTRACT FROM AUTHOR]

Proanthocyanidin (PAC) holds strong free radicals scavenging ability and is widely used as oxygen free radical scavenger. Huge demand, safety and economic aspect are forcing the PAC extraction to explore new resource and greener solvent. An efficient extraction method of PAC from Ginkgo biloba leaves was established by employing deep eutectic solvent (DES)-water mixture. After a rational design, a DES-water mixture (named as Ch-M 55 ) was chosen as the extraction solvent, which was prepared from choline chloride and malonic acid at a molar ratio of 1:2 with water addition of 55% (w/w). The main factors affecting the extraction yield were statistically optimized using a central composite design combined with response surface methodology (RSM). The optimal conditions were obtained as follows: extraction temperature of 65 °C, extraction time of 53 min and Ch-M 55 to solid ratio of 10.57:1 (v/w, mL/g). The PAC extraction yield was 22.19 ± 0.71 mg/g under the optimized conditions, which was much higher than those of conventional organic solvents. The antioxidant activity of PAC extracted by Ch-M 55 was similar to that of 70% acetone, but a little less than 70% methanol and 70% ethanol. The differences in constituent and polymerization degree of PAC extracted by different solvents might account for the difference in antioxidant activity. In consideration of biodegradability and pharmaceutical acceptability, the Ch-M 55 -based extraction method is obviously efficient, green and ecofriendly. Extraction of PAC from Ginkgo biloba leaves also provides a new PAC resource. [ABSTRACT FROM AUTHOR]