Time filter

Source Type

Li X.,Jiangnan University | Shen C.,Jiangnan University | Wu D.,Jiangnan University | Lu J.,Jiangnan University | And 3 more authors.
Journal of the Institute of Brewing | Year: 2015

Most of the fermented alcoholic beverages, particularly Chinese rice wine, contain the potentially human carcinogenic compound ethyl carbamate (EC). As a major EC precursor in Chinese rice wine, urea in fermentations can be transported into the yeast cell by urea permease and finally metabolized by urea carboxylase and allophanate hydrolase in vivo. To eliminate EC in Chinese rice wines, the present study constructed high urea uptake yeast strains N1-D, N2-D and N-D, by introducing a strong promoter (PGK1p) into the urea permease gene (DUR3) of the industrial Chinese rice wine yeast N85, and by the restoration of the URA3 gene at the same time. With these self-cloned, high urea uptake strains, the urea and EC in the terminal Chinese rice wine samples were reduced to different extents. With two copies of overexpressed DUR3, the N-D strain could reduce the urea and the EC by 53.4 and 26.1%, respectively. No difference in fermentation characteristics was found between the engineered strains and the parental industrial yeast strain N85. These results could help to optimize the genetic manipulation strategy for EC elimination in Chinese rice wine production. © 2015 The Institute of Brewing & Distilling.

Wu D.,Jiangnan University | Li X.,Jiangnan University | Shen C.,Jiangnan University | Lu J.,Jiangnan University | And 3 more authors.
Journal of the Institute of Brewing | Year: 2013

The complex metabolic processes of yeast influence wine fermentation and therefore the quality of wine. Wine yeasts, owing to their being typically prototrophic and often polyploid, have been restricted in terms of exploiting classical recombinant genetic techniques to improve their characteristics. To overcome this problem, haploids have been isolated from a commercial Chinese rice wine strain N85, by disruption of the HO gene. In this study, the Cre-loxP system and a removable G418r marker were used to construct an HO disruption cassette. Most of the heterologous sequences of constructed disruption cassette were successfully excised from the genome of the haploids by loop-out of the KanMX gene, through induced expression of the Cre recombinase. The removal of the resistant marker ensures the biological safety of the strains. As expected, no difference in fermentation capacity between the parental and the haploid strains was seen. The present work reports the construction of an HO disruption cassette by touchdown polymerase chain reaction and its application with a Chinese rice wine yeast for haploid isolation and to broaden physiological investigations and industrial applications. © 2013 The Institute of Brewing & Distilling.

Wang P.,Jiangnan University | Sun J.,Jiangnan University | Li X.,Jiangnan University | Wu D.,Jiangnan University | And 5 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2014

Ethyl carbamate is a well-known carcinogen and widely occurs in Chinese rice wine. To provide more clues to minimise ethyl carbamate accumulation, the levels of possible precursors of ethyl carbamate in Chinese rice wine were investigated by HPLC. Studies of the possible precursors of ethyl carbamate in Chinese raw rice wine with various additives and treatments indicated that significant amounts of urea can account for ethyl carbamate formation. It was also recognised that citrulline is another important precursor that significantly affects ethyl carbamate production during the boiling procedure used in the Chinese rice wine manufacturing process. Besides urea and citrulline, arginine was also found to be an indirect ethyl carbamate precursor due to its ability to form urea and citrulline by microorganism metabolism. © 2014 Taylor & Francis.

Wu D.,Jiangnan University | Li X.,Jiangnan University | Shen C.,Jiangnan University | Lu J.,Jiangnan University | And 3 more authors.
International Journal of Food Microbiology | Year: 2014

Saccharomyces cerevisiae metabolizes arginine to ornithine and urea during wine fermentations. In the fermentation of Chinese rice wine, yeast strains of S. cerevisiae do not fully metabolize urea, which will be secreted into the spirits and spontaneously reacts with ethanol to form ethyl carbamate, a potential carcinogenic agent for humans. To block the pathway of urea production, we genetically engineered two haploid strains to reduce the arginase (encoded by CAR1) activity, which were isolated from a diploid industrial Chinese rice wine strain. Finally the engineered haploids with opposite mating type were mated back to diploid strains, obtaining a heterozygous deletion strain (CAR1/. car1) and a homozygous defect strain (car1/. car1). These strains were compared to the parental industrial yeast strain in Chinese rice wine fermentations and spirit production. The strain with the homozygous CAR1 deletion showed significant reductions of urea and EC in the final spirits in comparison to the parental strain, with the concentration reductions by 86.9% and 50.5% respectively. In addition, EC accumulation was in a much lower tempo during rice wine storage. Moreover, the growth behavior and fermentation characteristics of the engineered diploid strain were similar to the parental strain. © 2014 Elsevier B.V.

Wu D.,Jiangnan University | Li X.,Jiangnan University | Lu J.,Jiangnan University | Chen J.,Jiangnan University | And 3 more authors.
FEMS Microbiology Letters | Year: 2015

Urea and ethanol are the main precursors of ethyl carbamate (EC) in Chinese rice wine. During fermentation, urea is generated from arginine by arginase in Saccharomyces cerevisiae, and subsequently cleaved by urea amidolyase or directly transported out of the cell into the fermentation liquor, where it reacts with ethanol to form EC. To reduce the amount of EC in Chinese rice wine, we metabolically engineered two yeast strains, N85DUR1,2 and N85DUR1,2-c, from the wild-type Chinese rice wine yeast strain N85. Both new strains were capable of constitutively expressing DUR1,2 (encodes urea amidolyase) and thus enhancing urea degradation. The use of N85DUR1,2 and N85DUR1,2-c reduced the concentration of EC in Chinese rice wine fermented on a small-scale by 49.1% and 55.3%, respectively, relative to fermentation with the parental strain. All of the engineered strains showed good genetic stability and minimized the production of urea during fermentation, with no exogenous genes introduced during genetic manipulation, and were therefore suitable for commercialization to increase the safety of Chinese rice wine. © FEMS 2015.

Xie G.,China Shaoxing Rice Wine Group Co. | Wang L.,China Shaoxing Rice Wine Group Co. | Gao Q.,Zhejiang University | Yu W.,Zhejiang University | And 3 more authors.
Journal of the Science of Food and Agriculture | Year: 2013

BACKGROUND: To understand the role of the community structure of microbes in the environment in the fermentation of Shaoxing rice wine, samples collected from a wine factory were subjected to Illumina-based metagenomic sequencing. RESULTS: De novo assembly of the sequencing reads allowed the characterisation of more than 23thousand microbial genes derived from 1.7 and 1.88 Gbp of sequences from two samples fermented for 5 and 30 days respectively. The microbial community structure at different fermentation times of Shaoxing rice wine was revealed, showing the different roles of the microbiota in the fermentation process of Shaoxing rice wine. The gene function of both samples was also studied in the COG database, with most genes belonging to category S (function unknown), category E (amino acid transport and metabolism) and unclassified group. CONCLUSION: The results show that both the microbial community structure and gene function composition change greatly at different time points of Shaoxing rice wine fermentation. © 2013 Society of Chemical Industry © 2013 Society of Chemical Industry.

Quan Z.,Shaoxing University | Xie G.,China Shaoxing Rice Wine Group Co. | Peng Q.,Shaoxing University | Shan J.,Shaoxing University | And 6 more authors.
Polish Journal of Environmental Studies | Year: 2016

A method for determining eight biogenic amines in surface water was established using high-performance liquid chromatography–triple quadrupole mass spectrometry to improve on the detection sensitivity of current methods. The limits of detection and quantification were 0.05 and 0.2 μg L-1, respectively, for histamine, cadaverine, spermine, and spermidine, 1.0 and 3.0 μg L−1, respectively, for putrescine, 1.5 and 5.0 μg L−1, respectively, for tyramine and tryptamine, and 2.0 and 5.0 μg L−1, respectively, for 2-phenylethylamine. The recovery of biogenic amines from spiked water samples was between 97.3 and 108.6% at levels between 0.05 and 15 μg L-1 (R > 0.999). The relative standard deviations were in the range of 0.10-0.29%. This method can achieve rapid and accurate determination of biogenic amines in surface water, and it meets the minimum residue measurement requirements. © 2016, HARD Publishing Company. All rights reserved.

Loading China Shaoxing Rice Wine Group Co. collaborators
Loading China Shaoxing Rice Wine Group Co. collaborators