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Objective: In order to improve the flavor and efficacy of traditional sweet-potato glutinous rice wine, optimize the fermentation process of pine-needle sweet-potato glutinous rice wine and evaluate its physicochemical indexes and antioxidant activity. Methods: Based on the traditional fermentation of sweet-potato rice wine, the fermentation conditions were optimized using a single-factor experiment and the response surface method. The effects of pine-needle addition, initial sugar content, fermentation time, yeast addition, solid-liquid ratio, and fermentation temperature on the fermentation process were investigated. The physicochemical indexes of the pine-needle sweet-potato glutinous rice wine obtained under the optimal fermentation conditions were evaluated. In addition, its antioxidant activity was analyzed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) cation free radical scavenging experiments. Results: The optimized fermentation conditions were as follows: pine needle mass addition of 3.3%, initial sugar content of 22.5°Bx, fermentation time of 7 d, yeast mass addition of 0.20%, solid (raw material mass):liquid (distilled water volume) ratio of 1:3 (g/mL), and fermentation temperature of 30 ℃. Under these conditions, the resulting pine-needle sweet-potato glutinous rice wine had a total sugar content of 12.5 g/L, alcohol content of 17.6%, and amino acid nitrogen content of 0.58 g/L. The resulting product exhibited a light-yellow transparent appearance with a unique pine-needle herb aroma. Moreover, it satisfied physical, chemical, and microbial safety standards. In terms of antioxidant capacity, the scavenging rates of the DPPH and ABTS+ free radicals of the pine-needle sweet-potato glutinous rice wine were as high as 87.2% and 90.3%, respectively, which were significantly higher than those of traditional sweet-potato glutinous rice wine (P

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to screen out Bacillus sp. with high production of antimicrobial lipopeptide and determine its optimal fermentation conditions, the study isolated and identified antimicrobial lipopeptide-producing Bacillus sp. strains from traditional fermented soybean paste, and adopted orthogonal test to investigate how lipopeptide production by Bacillus sp was affected by fermentation conditions, such as fermentation inoculum amount, fermentation filling volume, fermentation time and fermentation temperature. The results showed that 27 strains of Bacillus sp. were isolated and screened out from 9 portions traditional fermented soybean paste of the Northeast, among which 6 strains were identified by 16S rDNA as having the genes sfp, fenB and ituA for synthesizing lipopeptide. According to the determination of lipopeptide yield and inhibition effect, Bacillus subtilis SN-20 and Bacillus amyloliquefaciens SN-46 showed excellent performance with the yield of 106 and 72 mg of lipopeptide per unit, and strong inhibition effect on both gram-positive and negative indicator bacteria. The optimal fermentation process of Bacillus subtilis SN-20 was found to be 3% inoculum, 20% fermentation filler, 36 h fermentation time and 32 ℃. The optimal fermentation process of Bacillus subtilis SN-46 was 2% inoculum, 40% fermentation filler, 24 h fermentation time and 32 ℃. Under these conditions, the unit biomass yields of lipopeptides for the two strains of Bacillus before optimization were 106.11 and 76.23 mg/g, respectively. After optimization, they increased by 21.85% and 23.84%, respectively. The study results effectively increased the production of antimicrobial lipopeptides from Bacillus.

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking Jinding Xiehua Suli pear from Ningling County as the main raw material, lactic acid bacteria suitable for fermentation of pear juice were screened. The fermentation technology of Suli pear juice with lactic acid bacteria was optimized by orthogonal test based on single-factor experiments and the volatile component of the Suli pear juice with lactic acid bacteria after optimization were analyzed dynamically. The results showed that the best fermentation conditions were as follows: Rhamnose Lactobacillus:Lactobacillus acidophilus:Bifidum lactobacillus lactis=1:1:1 (V/V), the initial pH was 4.5, the amount of lactic acid bacteria addition was 4%, the amount of sugar addition was 10%, and the fermentation time was 50 h. Under this condition, the VC content was 14.17 mg/100 mL, the total acid content was 7.66 g/L, the total phenol content was 3.68 mg/mL, the total flavonoids content was 6.25 mg/mL, the DPPH free radical scavenging rate was 90.05%, and the sensory score was 80.60. The volatile components of Suli pear juice after 0, 30, 40 and 50 h fermentation were analyzed by the gas chromatography-mass spectrometry (GC-MS). A total of 55 volatile substances were detected. With the prolongation of fermentation time, the types and contents of volatile substances increased. There were 7 kinds of volatile components in the raw Suli pear juice, the volatile components of pear juice after 30 and 40 h fermentation were 27 kinds, and increased to 46 kinds of volatile components after 50 h fermentation when higher alcohols, higher esters and higher acids were produced in large quantities, which brought lactic acid bacteria the sour and sweet taste and unique flavor of Suli pear juice.

Staurosporine is the most well-known member of the indolocarbazole alkaloid family; it can induce apoptosis of many types of cells as a strong protein kinase inhibitor, and is used as an important lead compound for the synthesis of the antitumor drugs. However, the low fermentation level of the native producer remains the bottleneck of staurosporine production. Herein, integration of multi-copy biosynthetic gene cluster (BGC) in well characterized heterologous host and optimization of the fermentation process were performed to enable high-level production of staurosporine. First, the 22.5 kb staurosporine BGC was captured by CRISPR/Cas9-mediated TAR (transformation-associated recombination) from the native producer (145 mg/L), and then introduced into three heterologous hosts Streptomyces avermitilis (ATCC 31267), Streptomyces lividans TK24 and Streptomyces albus J1074 to evaluate the staurosporine production capacity. The highest yield was achieved in S. albus J1074 (750 mg/L), which was used for further production improvement. Next, we integrated two additional staurosporine BGCs into the chromosome of strain S-STA via two different attB sites (vwb and TG1), leading to a double increase in the production of staurosporine. And finally, optimization of fermentation process by controlling the pH and glucose feeding could improve the yield of staurosporine to 4568 mg/L, which was approximately 30-fold higher than that of the native producer. This is the highest yield ever reported, paving the way for the industrial production of staurosporine. Keypoints: • Streptomyces albus J1074 was the most suitable heterologous host to express the biosynthetic gene cluster of staurosporine. • Amplification of the biosynthetic gene cluster had obvious effect on improving the production of staurosporine. • The highest yield of staurosporine was achieved to 4568 mg/L by stepwise increase strategy. [ABSTRACT FROM AUTHOR]

To improve the cellulose degradation ability of Bacillus subtilis (B. subtilis), a strain with a higher cellulose degradation rate was selected from five B. subtilis strains as the starting strain in this experiment. By heavy ion irradiation mutagenesis treatment, we screened a high cellulose degradation rate strain, and optimized its fermentation conditions. The results showed that a B. subtilis CG-40-1 mutant strain cellulose degradation rate was （53.07±0.75）%, which was 17.75% higher than the starting strain and has good genetic stability. After the optimization experiment of fermentation conditions, the optimal fermentation time, culture temperature, and pH of this strain were 120 h, 45 ℃, and 6.5, respectively. And the cellulose degradation rate was (67.79±0.49)%, which was 27.74% higher than that without optimization.

In this study, red beans, black beans and soybeans were utilized to produce fermented mixed-bean milk. The changes of total phenols, total flavonoid and antioxidant capacity of the product were investigated by single factor experiment and response surface methodology. The results showed that the optimum fermentation process of fermented mixed-bean milk was sucrose addition of 7.2%, transglutaminase addition of 0.63 g/L and fermentation for 10 h accompanying the sensory score of 88.1 points. After digested with gastric juice and intestinal juice, the total phenols content in fermented mixed-bean milk were increased by 25% and 61%, while total flavonoid were increased by 51% and 22%. Before digestion, DPPH, ABTS, hydroxyl radical clearance and reducing power were 47.71%, 20.53%, 41.45% and 0.22 respectively. After gastrointestinal juice digestion, the antioxidant indexes were increased by 35.0%, 48.1%, 43.1% and 27.3% respectively. After intestinal juice digestion, the reducing power of fermented mixed-bean milk was 10% lower than that of gastric juice digestion, but still higher than that of undigested sample. The total phenols content after digestion was positively correlated with DPPH radical scavenging rate, ABTS and hydroxyl radical scavenging rate (P < 0.05) and there was a positive correlation between total flavonoid and reducing power (P < 0.05). Consequently, the results could provide a reference for the future research and development of fermented mixed-bean milk.

The nattokinase propeptide acts as an intramolecular chaperone that is essential for the correct folding of the mature peptide. Understanding key catalytic regions and sites in this propeptide is crucial for enhancing the nattokinase folding efficiency. Through bioinformatics and enzyme activity screening, we pinpointed critical sites affecting folding efficiency and identified mutants Y106V and A103T. In fermentation, their crude enzyme activities reached 277.83 and 205.63% of those of WT, respectively. Mutant Y106V exhibited a 19.2% increase in the specific enzyme activity, improving both the folding efficiency and peptide conformation. Molecular dynamics simulations elucidated the catalytic changes in Y106V and A103T. Optimization of fermentation processes for these mutants yielded nattokinase levels of 317.042 and 336.65 U/mL. This study lays a foundation for further research on nattokinase propeptide function and modification.

2-Phenylethanol is a valuable flavoring agent with many applications. Although the bioproduction of 2-phenylethanol has been achieved by microbial fermentation, the low titer and high cost hinder its industrial-scale production. The goal of this study is to develop an efficient process for high-level production of 2-phenylethanol from L-phenylalanine. Firstly, candidate hosts for 2-phenylethanol synthesis were screened by evaluating their tolerance to 2-phenylethanol, and Bacillus licheniformis DW2 was proven to be a promising strain for 2-phenylethanol production. Subsequently, phenylpyruvate decarboxylase and alcohol dehydrogenase from different hosts were screened, and the combination of KivD from Lactococcus lactis and YqhD from Escherichia coli owned the best performance on 2-phenylethanol synthesis, and the attained strain DE4 produced 3.04 g/L 2-phenylethanol from 5.00 g/L L-phenylalanine using glucose as carbon source. Furthermore, the fermentation process was optimized using molasses as carbon source, and 2-phenylethanol titer was increased to 4.41 g/L. In fed-batch fermentation, the maximum 2-phenylethanol titer reached 5.16 g/L, with a yield of 0.65 g/g on L-phenylalanine and productivity of 0.12 g/(L.h), which was the highest 2-phenylethnol titer reported to date when molasses was used as carbon source. Collectively, this study develops a robust strain as well as the cost-efficient process for 2-phenylethanol production, which lays a substantial foundation for industrial production of 2-phenylethanol. Key points •Bacillus licheniformis is an excellent 2-PE stress-tolerant strain. •Coexpressed kivD and yqhD is most suitable for 2-PE production in B. licheniformis. •High-level production of 2-PE (5.16 g/L) was obtained by engineered strain DE4. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) are polyesters intracellularly accumulated by various microorganisms as carbon and energy storage materials. The most common representative is poly-β-hydroxybutyrate (PHB). These biopolymers have been considered to be good substitutes for petroleum-derived synthetic plastics because of their similar properties to synthetic polymers and its complete biodegradability after disposal. Nevertheless a major drawback to the commercialisation of PHAs is their much higher production cost compared with petrochemical-based synthetic plastic materials. Optimization of fermentation process is one of the strategies more used to reducing high production costs of PHB. The aims of this work were to determine the optimal initial pH value for PHB production, as well as to optimize the agitation-aeration conditions of the fermentation process for product-biomass yield and for PHB accumulation by Rhizobium tropici strain 3. Optimization of initial pH was carried out in an orbital shaker. The pH values were adjusted between 6 and 8. The relation between pH and PHB concentration (g ⋅ L-1 ) was modelled by using orthogonal polynomials. The optimal pH that assures the biggest PHB production is 6.58 ± 0.2. As statistical tools, a central compose design Box-Wilson was used to search the optimal values of two important variables in fermentation process: agitation-aeration rates, for PHB production and for product-biomass yield. The fermentations were carried out in a bioreactor with 7.5 L capacity with 5 L of optimum culture medium. It was determined that optimal values to obtain a maximum PHB production are 500 r ⋅ min-1 and 1 vvm (volumes of air per minute per volume of batch) for agitation and aeration respectively and for product-biomass yield optimal values are 472 r ⋅ min-1 and 1.55 vvm. [ABSTRACT FROM AUTHOR]