title: [Physiological response to acetic acid stress of Acetobacter pasteuranus during vinegar fermentation].
abstract: OBJECTIVE
  The aim of the study is to propose a dynamic acetic acid resistance mechanism through analysis on response of cellular morphology, physiology and metabolism of A. pasteurianus CICIM B7003 during vinegar fermentation.
  
  
  METHODS
  Vinegar fermentation was carried out in a Frings 9 L acetator by strain B7003 and cultures were sampled at different cellular growth phases. Simultaneously, percentage of capsular polysaccharide versus dry cells weight, ratio of unsaturated fatty acids to saturated fatty acids, transcription of acetic acid resistance genes, activity of alcohol respiratory chain enzymes and ATPase were detected for these samples to assay the responses of bacterial morphology, physiology and metabolism.
  
  
  RESULTS
  When acetic acid was existed, no obvious capsular polysaccharide was secreted by cells. As vinegar fermentation proceeding, percentage of capsular polysaccharide versus dry cells weight was reduced from 2.5% to 0.89%. Ratio of unsaturated fatty acids to saturated fatty acids was increased obviously which can improve membrane fluidity. Also transcription level of acetic acid resistance genes was promoted. Interestingly, activity of alcohol respiratory chain and ATPase was not inhibited but promoted obviously with acetic acid accumulation which could provide enough energy for acetic acid resistance mechanism.
  
  
  CONCLUSIONS
  On the basis of the results obtained from the experiment, A. pasteurianus CICIM B7003 relies mainly on the cooperation of changes of extracellular capsular polysaccharide and membrane fatty acids, activation of acid resistance genes transcription, enhancement of activity of alcohol respiratory chain and rapid energy production to tolerate acidic environment.
authors.forename: Zhengliang
authors.initials: Z
authors.lastname: Qi
authors.forename: Hailin
authors.initials: H
authors.lastname: Yang
authors.forename: Xiaole
authors.initials: X
authors.lastname: Xia
authors.forename: Wu
authors.initials: W
authors.lastname: Wang
authors.forename: Yunwei
authors.initials: Y
authors.lastname: Leng
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Yu
authors.forename: Wu
authors.initials: W
authors.lastname: Quan
mesh_terms: D000085:Acetates / Q000378:metabolism; D019342:Acetic Acid / Q000378:metabolism*; D000091:Acetobacter / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005285:Fermentation; D007218:Industrial Microbiology
chemical_list: D000085:Acetates; D005227:Fatty Acids; D000431:Ethanol; D019342:Acetic Acid