Screening of a Saccharomyces cerevisiae Strain with High 3-Methylthio-1-Propanol Yield and Optimization of Its Fermentation Conditions.

3-Methylthio-1-propanol (3-Met) is an important flavor compound in various alcoholic beverages such as Baijiu and Huangjiu. To maintain the content of 3-Met in these alcoholic beverages, it is necessary to screen a micro-organism with high yield of 3-Met from the brewing environment. In this study, the ability of yeast strains from the Baijiu brewing to produce 3-Met was analyzed, aiming to obtain yeast with high-yield 3-Met, and its fermentation conditions were optimized. Firstly, 39 yeast strains were screened using 3-Met conversion medium. The results showed that the majority of the strains from Baijiu brewing sources could produce 3-Met, and nearly half of the strains produced more than 0.5 g/L of 3-Met. Among these, yeast F10404, Y03401, and Y8#01, produced more than 1.0 g/L of 3-Met, with yeast Y03401 producing the highest amount at 1.30 g/L. Through morphological observation, physiological and biochemical analysis, and molecular biological identification, it was confirmed that yeast Y03401 was a Saccharomyces cerevisiae. Subsequently, the optimal fermentation conditions for 3-Met production by this yeast were obtained through single-factor designs, Plackett-Burman test, steepest ascent path design and response surface methodology. When the glucose concentration was 60 g/L, yeast extract concentration was 0.8 g/L, L-methionine concentration was 3.8 g/L, initial pH was 4, incubation time was 63 h, inoculum size was 1.6%, shaking speed was 150 rpm, loading volume was 50 mL/250 mL, and temperature was 26 °C, the content of 3-Met produced by S. cerevisiae Y03401 reached a high level of 3.66 g/L. It was also noteworthy that, in contrast to other study findings, this yeast was able to create substantial amounts of 3-Met even in the absence of L-methionine precursor. Based on the clear genome of S. cerevisiae and its characteristics in 3-Met production, S. cerevisiae Y03401 had broad prospects for application in alcoholic beverages such as Baijiu.

Heterologous Expression of Phycocyanobilin in Escherichia coli and Determination of Its Antioxidant Capacity In Vitro.

Phycocyanobilin (PCB) is a blue pigment with antioxidant, anti-inflammatory, and anticancer properties. It is used in the medical and cosmetic industries. In this study, a high-expression plasmid, pET-30a-PCB, was constructed for expression of PCB in Escherichia coli BL21(DE3). The PCB was analyzed using UV-visible absorption spectrum, MALDI-TOF-MS, and fluorescence spectra. The stability and half-life of PCB in different serum were determined. The yield of PCB was optimized through single-factor and orthogonal experiments. The optimal expression conditions were determined as a lactose concentration of 5 mmol/L, an induction time of 8 h, an induction temperature of 27 °C, and an induction duration of 22 h. PCB yield of 6.5 mg/L was achieved and subsequently purified using nickel-affinity chromatography. The purified PCB was quantified indirectly using Hist-tag ELISA detection, and the concentration was 11.66 µg/L. In the range of 0-33 µg/mL, the total antioxidant capacity and reducing the capacity of PCB were stronger than Vitamin E (Ve), with 1,1-diphenyl-2-picrylhydrazil (DPPH) scavenging reaching up to 87.07%, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) free radical (ABTS) scavenging up to 100%, hydroxyl radicals (·OH) scavenging up to 64.19%, hydrogen peroxide (H2O2) scavenging up to 78.75%, This study provides theoretical evidence for PCB as a potent antioxidant.

Screening, Identification, and Fermentation Condition Optimization of a High-Yield 3-Methylthiopropanol Yeast and Its Aroma-Producing Characteristics.

A high-yield 3-methylthiopropanol (3-Met) yeast Y1402 was obtained from sesame-flavored Daqu, and it was identified as Saccharomycopsis fibuligera. S. fibuligera Y1402 showed a broad range of growth temperatures and pH, as well as the maximum tolerance to glucose, NaCl, nicotine, and 3-Met at 50% (w/w), 15% (w/v), 1.2 g/L, and 18 g/L, respectively. After optimization using single-factor experiments, a Plackett-Burman design, a steepest ascent test, and a Box-Behnken design, the 3-Met yield reached 4.03 g/L by S. fibuligera Y1402 under the following optimal conditions: glucose concentration of 40 g/L, yeast extract concentration of 0.63 g/L, Tween 80 concentration of 2 g/L, L-methionine concentration of 5 g/L, liquid volume of 25 mL/250 mL, initial pH of 5.3, fermentation temperature of 32 °C, inoculum size of 0.8%, shaking speed of 210 rpm, and fermentation time of 54 h. The fermentation was scaled up to a 3 L fermenter under the optimized conditions, and the yield of 3-Met reached 0.71 g/L. Additionally, an aroma analysis revealed that the flavor substances produced by S. fibuligera Y1402 in sorghum hydrolysate medium was mainly composed of compounds with floral, sweet, creamy, roasted nut, and clove-like aromas. Therefore, S. fibuligera has great potential for application in the brewing of Baijiu and other fermented foods.

Response Surfaces Method and Artificial Intelligence Approaches for Modeling the Effects of Environmental Factors on Chlorophyll a in Isochrysis galbana.

This study reported the condition optimization for chlorophyll a (Chl a) from the microalga Isochrysis galbana. The key parameters affecting the Chl a content of I. galbana were determined by a single-factor optimization experiment. Then the individual and interaction of three factors, including salinity, pH and nitrogen concentration, was optimized by using the method of Box-Benhnken Design. The highest Chl a content (0.51 mg/L) was obtained under the optimum conditions of salinity 30‱ and nitrogen concentration of 72.1 mg/L at pH 8.0. The estimation models of Chl a content based on the response surfaces method (RSM) and three different artificial intelligence models of artificial neural network (ANN), support vector machine (SVM) and radial basis function neural network (RBFNN), were established, respectively. The fitting model was evaluated by using statistical analysis parameters. The high accuracy of prediction was achieved on the ANN, SVM and RBFNN models with correlation coefficients (R2) of 0.9113, 0.9127, and 0.9185, respectively. The performance of these artificial intelligence models depicted better prediction capability than the RSM model for anticipating all the responses. Further experimental results suggested that the proposed SVM and RBFNN model are efficient techniques for accurately fitting the Chl a content of I. galbana and will be helpful in validating future experimental work on the Chl a content by computational intelligence approach.

Optimization of Heterotrophic Culture Conditions for the Algae Graesiella emersonii WBG-1 to Produce Proteins.

The aim of this study was to improve the protein content and yield of heterotrophic microalgal cultivation and establish a simple, economical, and efficient method for microalgal protein production using the novel green alga, Graesiella emersonii WBG-1, which has not been previously reported for heterotrophic cultivation. Through batch heterotrophic cultivation of this alga, we observed that glucose was the optimal carbon source, while it could not use sucrose as a carbon source. Biomass production and protein content were significantly reduced when sodium acetate was used as the carbon source. Compared with nitrate, protein content increased by 93% when urea was used as the nitrogen source. Cultivation temperature had a significant impact on biomass production and protein content. The optimal conditions were glucose as the carbon source at an initial concentration of 10 g/L, urea as the nitrogen source at an initial concentration of 1.62 g/L, and a culture temperature of 35 °C. On the second day of batch cultivation, the highest protein content (66.14%) was achieved, which was significantly higher than that reported in heterotrophic cultures of Chlorella and much higher than that reported for specially established technologies aimed at increasing the protein content, such as two-stage heterotrophic, heterotrophy-dilution-photoinduction, and mixotrophic processes. These results demonstrate the great potential of the heterotrophic cultivation of G. emersonii WBG-1 for protein production.

Sodium-Ion-Free Fermentative Production of GABA with Levilactobacillus brevis CD0817.

Gamma-aminobutyric acid (GABA) has positive effects on many physiological processes. Lactic acid bacterial production of GABA is a future trend. This study aimed to produce a sodium-ion-free GABA fermentation process for Levilactobacillus brevis CD0817. In this fermentation, both the seed and fermentation media used L-glutamic acid instead of monosodium L-glutamate as the substrate. We optimized the key factors influencing GABA formation, adopting Erlenmeyer flask fermentation. The optimized values of the key factors of glucose, yeast extract, Tween 80, manganese ion, and fermentation temperature were 10 g/L, 35 g/L, 1.5 g/L, 0.2 mM, and 30 °C, respectively. Based on the optimized data, a sodium-ion-free GABA fermentation process was developed using a 10-L fermenter. During the fermentation, L-glutamic acid powder was continuously dissolved to supply substrate and to provide the acidic environment essential for GABA synthesis. The current bioprocess accumulated GABA at up to 331 ± 8.3 g/L after 48 h. The productivity of GABA was 6.9 g/L/h and the molar conversion rate of the substrate was 98.1%. These findings demonstrate that the proposed method is promising in the fermentative preparation of GABA by lactic acid bacteria.

Analysis of aptamer-target binding and molecular mechanisms by thermofluorimetric analysis and molecular dynamics simulation.

Introduction: Aptamers are valuable for bioassays, but aptamer-target binding is susceptible to reaction conditions. In this study, we combined thermofluorimetric analysis (TFA) and molecular dynamics (MD) simulations to optimize aptamer-target binding, explore underlying mechanisms and select preferred aptamer. Methods: Alpha-fetoprotein (AFP) aptamer AP273 (as the model) was incubated with AFP under various experimental conditions, and melting curves were measured in a real-time PCR system to select the optimal binding conditions. The intermolecular interactions of AP273-AFP were analysed by MD simulations with these conditions to reveal the underlying mechanisms. A comparative study between AP273 and control aptamer AP-L3-4 was performed to validate the value of combined TFA and MD simulation in selecting preferred aptamers. Results: The optimal aptamer concentration and buffer system were easily determined from the dF/dT peak characteristics and the melting temperature (Tm) values on the melting curves of related TFA experiments, respectively. A high Tm value was found in TFA experiments performed in buffer systems with low metal ion strength. The molecular docking and MD simulation analyses revealed the underlying mechanisms of the TFA results, i.e., the binding force and stability of AP273 to AFP were affected by the number of binding sites, frequency and distance of hydrogen bonds, and binding free energies; these factors varied in different buffer and metal ion conditions. The comparative study showed that AP273 was superior to the homologous aptamer AP-L3-4. Conclusion: Combining TFA and MD simulation is efficient for optimizing the reaction conditions, exploring underlying mechanisms, and selecting aptamers in aptamer-target bioassays.

Corrigendum: Improvement of antioxidant activity and active ingredient of Dendrobium officinale via microbial fermentation.

[This corrects the article DOI: 10.3389/fmicb.2023.1061970.].

Construction and application of the genome-scale metabolic model of Streptomyces radiopugnans.

Geosmin is one of the most common earthy-musty odor compounds, which is mainly produced by Streptomyces. Streptomyces radiopugnans was screened in radiation-polluted soil, which has the potential to overproduce geosmin. However, due to the complex cellular metabolism and regulation mechanism, the phenotypes of S. radiopugnans were hard to investigate. A genome-scale metabolic model of S. radiopugnans named iZDZ767 was constructed. Model iZDZ767 involved 1,411 reactions, 1,399 metabolites, and 767 genes; its gene coverage was 14.1%. Model iZDZ767 could grow on 23 carbon sources and five nitrogen sources, which achieved 82.1% and 83.3% prediction accuracy, respectively. For the essential gene prediction, the accuracy was 97.6%. According to the simulation of model iZDZ767, D-glucose and urea were the best for geosmin fermentation. The culture condition optimization experiments proved that with D-glucose as the carbon source and urea as the nitrogen source (4 g/L), geosmin production could reach 581.6 ng/L. Using the OptForce algorithm, 29 genes were identified as the targets of metabolic engineering modification. With the help of model iZDZ767, the phenotypes of S. radiopugnans could be well resolved. The key targets for geosmin overproduction could also be identified efficiently.

Improvement of antioxidant activity and active ingredient of Dendrobium officinale via microbial fermentation.

This study used brewer's yeast to ferment Dendrobium officinale and single-factor and orthogonal experiments were conducted to determine the optimal fermentation conditions. The antioxidant capacity of Dendrobium fermentation solution was also investigated by in vitro experiments, which showed that different concentrations of fermentation solution could effectively enhance the total antioxidant capacity of cells. The fermentation liquid was found to contain seven sugar compounds including glucose, galactose, rhamnose, arabinose, and xylose using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF-MS), with the highest concentrations of glucose and galactose at 194.628 and 103.899 µg/ml, respectively. The external fermentation liquid also contained six flavonoids with apigenin glycosides as the main structure and four phenolic acids including gallic acid, protocatechuic acid, catechol, and sessile pentosidine B.

Metabolic engineering of Escherichia coli for biological production of 1, 3-Butanediol.

The production of 1,3-butanediol (1,3-BDO) from glucose was investigated using Escherichia coli as the host organism. A pathway was engineered by overexpressing genes phaA (acetyl-CoA acetyltransferase), phaB (acetoacetyl-CoA reductase), bld (CoA-acylating aldehyde dehydrogenase), and yqhD (alcohol dehydrogenase). The expression levels of these genes were optimized to improve 1,3-BDO production and pathways that compete with 1,3-BDO synthesis were disrupted. Culture conditions were also optimized, including the C: N ratio, aeration, induction time, temperature, and supplementation of amino acids, resulting in a strain that could produce 1,3-BDO at 257 mM in 36 h, with a yield of 0.51 mol/mol in a fed-batch bioreactor experiment. To the best of our knowledge, this is the highest titer of 1,3-BDO production ever reported using biological methods, and our findings provide a promising strategy for the development of microbial cell factories for the sustainable synthesis of other acetyl-CoA-derived chemicals.

Quartz Crystal Microbalance Technology Coupled with Impedance for the Dynamic Monitoring of the Cardiomyocyte Beating Function and Drug Screening.

The main sensing techniques used to study myocardial pulsation are electrical impedance sensing (EIS) and by quartz crystal microbalance (QCM). While electrical impedance technology is the gold standard for the study of myocardial pulsation, the clinical application of drugs is being followed up in real time additionally, thus, QCM technology needs to be further developed as a very important class of quality sensor technology. Moreover, the application of EIS, in combination with the QCM, for monitoring myocardial pulsation, has been rarely reported. In this paper, a series of cell growth and adhesion conditions were optimized using rat primary cardiomyocytes, and QCM was used in combination with EIS to monitor the adhesion and the myocardial pulsation ability of the cells in real time. Furthermore, cardiomyocytes that adhered to the QCM and EIS were treated with isoprenaline (ISO), a positive inotropic drug, and verapamil (VRP), a negative inotropic drug. Next, the cell index (CI)-time (T) plots, beating amplitude (BA) and beating rate (BR) of the cardiomyocytes were calculated and changes in these parameters, before and after, dosing were evaluated. The results showed that the QCM technique results were not only consistent with the results obtained with EIS, but also that the QCM technique had a certain degree of sensitivity for the calculation of cardiomyocyte beating. Thus, our findings validate the reliability and validity of the QCM technique for measuring cardiomyocyte beating and drug testing. We hope that further studies would evaluate the application of the QCM technology for clinical use.

Condition optimization of iron-air fuel cell to treat phosphate-containing wastewater regarding sustainable development.

Increasing use of phosphorus products and excessive exploitation of phosphorus resources become two major problems in perspective of phosphorus sustainable development. Phosphorus recovery is the shortcut to solve this dilemma. Combining electrochemistry, an iron-air fuel cell was adopted to recover phosphate and electricity from phosphate-containing wastewater in our previous studies. The present study focused on investigating the effects of catholyte/anolyte conductivity, external resistance, and anolyte pH on the performance of iron-air fuel cell, and obtaining the optimized conditions. Furthermore, the electrochemical methods of phosphate recovery were compared and assessed, and it is concluded that iron-air fuel cell has great potential for energy recovery. The phosphate removal efficiencies and vivianite yield roughly positively correlated with the catholyte conductivity and the anolyte pH, but negatively correlated with the external resistance and the anolyte conductivity. The electricity generation roughly positively correlated with the catholyte conductivity and anolyte conductivity, but showed limitations in the test range of anolyte pH and external resistance. To pursue high phosphate removal efficiencies and vivianite yield, the catholyte conductivity, external resistance, anolyte pH and anolyte conductivity were suggested to be 35 g-NaCl/L, 10 Ω, 8 and 0 g-NaCl/L. While if electricity generation was the primary goal, these parameters should be 35 g-NaCl/L, 220 Ω, 5 and 70 g-NaCl/L. The optimized conditions will help to improve the phosphate removal efficiency, vivianite yield and electricity generation, and to promote the development of iron-air fuel cell technology.

Incidence and risk factors for surgical site infection following volar locking plating (VLP) of unstable distal radius fracture (DRF).

PURPOSE: Volar locking plating (VLP) is the mainstay of treatment for distal radius fracture (DRF) but may be compromised by postoperative surgical site infection (SSI). This study aimed to identify the incidence and the risk factors for SSI following VLP of DRF. METHODS: This retrospective study identified consecutive patients who underwent VLP for closed unstable DRFs in our institution between January 2015 and June 2021. Postoperative SSI was identified by inquiring the medical records, the follow-up records or the readmission medical records for treatment of SSI. The potential factors for SSI were extracted from the medical records. Univariate and multivariate logistic regression analyses were performed to identify the independent factors. RESULTS: There were 930 patients included, and 34 had an SSI, representing an incidence of 3.7% (95% CI 2.4-4.9%). Patients with an SSI had threefold extended hospitalization stay (44.1 ± 38.2 versus 14.4 ± 12.5 days) as did those without. In univariate analysis, 18 variables were tested to be statistically different between SSI and non-SSI group. In multivariate analysis, 6 factors were identified as independently associated with SSI, including sex (male vs. female, OR 3.5, p = 0.014), ASA (III and IV vs. I, OR 3.2, p = 0.031), smoking (yes vs. no, OR 2.4, p = 0.015), bone grafting (OR 4.0, p = 0.007), surgeon volume (low vs. high, OR 2.7, p 0.011) and operation at night-time (vs. day-time, OR 7.8, p < 0.001). CONCLUSION: The postoperative SSI of VLP of DRF was not uncommon, and the factors identified in this study, especially those modifiable, would help identify individual SSI risk, target clinical surveillance and inform patient counseling.

Extracellular expression of agarolytic enzymes in Clostridium sp. strain and its application for butanol production from Gelidium amansii.

In this study, Clostridium sp. strain WK-AN1 carrying both genes of agarase (Aga0283) and neoagarobiose hydrolase (NH2780) were successfully constructed to convert agar polysaccharide directly into butanol, contributing to overcome the lack of algal hydrolases in solventogenic clostridia. Through the optimization by the Plackett-Burman design (PBD) and response surface methodology (RSM), a maximal butanol production of 6.42 g/L was achieved from 17.86 g/L agar. Further application of utilizing the butyric acid pretreated Gelidium amansii hydrolysate demonstrated the modified strain obtained the butanol production of 7.83 g/L by 1.63-fold improvement over the wild-type one. This work for the first time establishes a novel route to utilize red algal polysaccharides for butanol fermentation by constructing a solventogenic clostridia-specific secretory expression system for heterologous agarases, which will provide insights for future development of the sustainable third-generation biomass energy.

Design and application of an efficient cellulose-degrading microbial consortium and carboxymethyl cellulase production optimization.

Microbial consortia with high cellulase activities can speed up the composting of agricultural wastes with high cellulose contents and promote the beneficial utilization of agricultural wastes. In this paper, rabbit feces and sesame oil cake were used as feedstocks for compost production. Cellulose-degrading microbial strains were isolated from compost samples taken at the different composting stages and screened via Congo red staining and filter paper degradation test. Seven strains, Trichoderma reesei, Escherichia fergusonii, Proteus vulgaris, Aspergillus glaucus, Bacillus mycoides, Corynebacterium glutamicum, and Serratia marcescens, with high activities of carboxymethyl cellulase (CMCase), filter paper cellulase (FPase), and ß-glucosidase (ß-Gase) were identified and selected for consortium design. Six microbial consortia were designed with these strains. Compared with the other five consortia, consortium VI composed of all seven strains displayed the highest cellulase activities, 141.89, 104.56, and 131.18 U/ml of CMCase, FPase, and ß-Gase, respectively. The single factor approach and response surface method were employed to optimize CMCase production of consortium VI. The optimized conditions were: culture time 4.25 days, culture temperature 35.5°C, pH 6.6, and inoculum volume 5% (v/v). Under these optimized conditions, the CMCase activity of consortium VI was up to 170.83 U/ml. Fermentation experiment of rabbit feces was carried out by using the consortium VI cultured under the optimal conditions. It was found that the application effect was better than other treatments, and the fermentation efficiency and nutrient content of the pile were significantly improved. This study provides a basis for the design of microbial consortia for the composting of agricultural wastes with high cellulose contents and provides a support for beneficial utilization of agricultural wastes.

Fabrication and characterization of Ti/polyaniline-Co/PbO2-Co for efficient electrochemical degradation of cephalexin in secondary effluents.

The traditional interlayer of PbO2 electrode possessed many problems, such as short service lifetime and limited specific surface area. Herein, a novel and efficient Ti/polyaniline-Co/PbO2-Co electrode was conctructed employing cyclic voltammetry to introduce a Co-doped polyaniline interlayer and anodic electrodeposition to synthetize a ß-PbO2-Co active layer. Compared with pristine PbO2 electrode, Ti/polyaniline-Co/PbO2-Co exhibited more compact crystalline shape and higher active sites amounts. Pratically, the electrochemical degradation of 5 mg L-1 cephalexin in real secondary effluents was effectively achieved by the novel anode with 87.42% cephalexin removal and 71.8% COD mineralization after 120 min of 15 mA cm-2 electrolysis. The hydroxyl radical production and electrochemical stability were increased by 3.16 and 3.27 times respectively. The cephalexin degradation pathway was investigated by combining a density functional theory-based theoretical approach and LC-QTrap-MS/MS. The most likely cleavage point of the ß-lactam ring was the O=C-N bond, whose attack would produce small molecular compounds containing the thiazole and 4, 6-thiazine rings. Further oxidation produced inorganic ions; quantitative investigations indicated the amino groups to undergo decomposition to form aqueous NH4+, which was further oxidized to NO3-. The accumulation of NO3- and SO42-, combined with a decrease in toxicity toward Escherichia coli, demonstrated the efficient mineralization of cephalexin on the Ti/polyaniline-Co/PbO2-Co electrode.

Optimization of environmental factors in a dual in vitro biofilm model of Candida albicans-Streptococcus mutans.

The biofilm formation of Streptococcus mutans-Candida albicans is an important virulence factor for dental caries. The purpose of this study was to determine the effect of some environmental conditions on the biofilm formation like inoculation concentration, temperature, sugar, amino acid, metal ions and saliva, and then establish a persistent in vitro biofilm model for further research. Based on the single factor experiment, the factors participating in the biofilm formation including sugar, inoculation concentration, and saliva increased the biofilm mass, while amino acid, metal ions, temperatures reduced biofilm mass. Optimal conditions for biofilm formation were the inoculation dosage of S. mutans and C. albicans of 108 and 107 , respectively, the addition of 0·3 g l-1 sucrose and sterile saliva. These results contribute to a deep understanding of the factors involved in oral biofilm formation of the important cariogenic pathogen S. mutans and the opportunistic pathogen C. albicans to study better for biofilm and promote the design of new therapeutic approaches. The present research also provides a model for evaluating the therapeutic potential for drugs in the future.

Construction of efficient enzyme systems for preparing chiral ethyl 3-hydroxy-3-phenylpropionate.

Ethyl 3-hydroxy-3-phenylpropionate (EHPP), (R)-EHPP or (S)-EHPP, is an important chiral intermediate for pharmaceuticals. Its synthesis from ethyl benzoyl acetate (EBA) by alcohol dehydrogenase is regarded as a green method. However, scarcely any alcohol dehydrogenase has been reported competent in asymmetric synthesis of chiral EHPP at high EBA loading. Present study developed two robust and efficient bio-catalysts Mu-S2 and Mu-R4 for preparation of (S)-EHPP and (R)-EHPP respectively by rational design of alcohol dehydrogenase PcSDR from Pedobacter chitinilyticus based on molecular dynamics (MD) simulation analysis. BtGDH, a glucose dehydrogenase from Bacillus toyonensis catalyzing the oxidation of glucose for cofactor regeneration, was co-expressed with the screened mutants to form enzyme systems Mu-S2-BtGDH and Mu-R4-BtGDH. After reaction condition optimization, Mu-S2-BtGDH and Mu-R4-BtGDH were efficient in the synthesis of (S)-EHPP (94% conv. and 99% e.e.) and (R)-EHPP (99% conv. and 98% e.e.) respectively in 100 mL scale under 500 mM of EBA loading in 10 h following a substrate continuous feeding mode. After purifying, the isolated yield for each EHPP enantiomer is > 93%. This work not only provides potential biocatalysts for the industrial production of (R)-EHPP and (S)-EHPP, but also enriches the constructure-function relationship of alcohol dehydrogenases.

One-pot fermentation for erythritol production from distillers grains by the co-cultivation of Yarrowia lipolytica and Trichoderma reesei.

A co-fermentation process involving Yarrowia lipolytica and Trichoderma reesei was studied, using distillers grains (DGS) as feedstocks for erythritol production. DGS can be effectively hydrolyzed by cellulase in the single-strain culture of T. reesei. One-pot solid state fermentation for erythritol production was then established by co-cultivating Y. lipolytica M53-S with the 12 h delay inoculated T. reesei Rut C-30, in which efficient saccharification of DGS and improved production of erythritol were simultaneously achieved. The 10:1 inoculation proportion of Y. lipolytica and T. reesei contributed to the maximum erythritol production of 267.1 mg/gds under the optimal conditions including initial moisture of 55%, pH of 5.0, NaCl addition of 0.02 g/gds and DGS mass of 200 g in 144 h co-cultivation. Being compared with the attempts to produce erythritol from other raw materials, the one-pot SSF with DGS is proposed to be a potential strategy for efficient and economical erythritol production.