title: Screening and characterization of ethanol-tolerant and thermotolerant acetic acid bacteria from Chinese vinegar Pei.
abstract: Acetic acid bacteria (AAB) are important microorganisms in the vinegar industry. However, AAB have to tolerate the presence of ethanol and high temperatures, especially in submerged fermentation (SF), which inhibits AAB growth and acid yield. In this study, seven AAB that are tolerant to temperatures above 40 °C and ethanol concentrations above 10% (v/v) were isolated from Chinese vinegar Pei. All the isolated AAB belong to Acetobacter pasteurianus according to 16S rDNA analysis. Among all AAB, AAB4 produced the highest acid yield under high temperature and ethanol test conditions. At 4% ethanol and 30-40 °C temperatures, AAB4 maintained an alcohol-acid transform ratio of more than 90.5 %. High alcohol-acid transform ratio was still maintained even at higher temperatures, namely, 87.2, 77.1, 14.5 and 2.9% at 41, 42, 43 and 44 °C, respectively. At 30 °C and different initial ethanol concentrations (4-10%), the acid yield by AAB4 increased gradually, although the alcohol-acid transform ratio decreased to some extent. However, 46.5, 8.7 and 0.9% ratios were retained at ethanol concentrations of 11, 12 and 13%, respectively. When compared with AS1.41 (an AAB widely used in China) using a 10 L fermentor, AAB4 produced 42.0 g/L acetic acid at 37 °C with 10% ethanol, whereas AS1.41 almost stopped producing acetic acid. In conclusion, these traits suggest that AAB4 is a valuable strain for vinegar production in SF.
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Li
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China.|Hubei Tulaohan Flavouring and Food Co.,Ltd., Research and Development Center, Yichang, 443000, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
authors.affiliation: Hubei Collaborative Innovation Center for Industrial Fermentation, Research Center of Food Fermentation Engineering and Technology of Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Pharmaceutical Engineering, Hubei University of Technology, Wuhan, 430068, China. huyonghugong@163.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
mesh_terms: D019342:Acetic Acid; D000091:Acetobacter / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D001483:Base Sequence; D002681:China; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation; D005516:Food Microbiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability; D010802:Phylogeny
chemical_list: D004275:DNA, Ribosomal; D000431:Ethanol; D019342:Acetic Acid
keywords: Acetic acid bacteria; Ethanol tolerance; Isolate; Thermotolerance; Vinegar Pei