Study On The Diversity Of Acetic Acid Bacteria In Traditional Vinegar Of Gansu Province And Screening Of Acetic Acid Bacteria

The classification and identification of acetic acid bacteria and its diversity was the basisof development and utilization acetic acid bacteria. The methods of classic plate isolated andcultured, physiological and biochemical identification, diversity of acetic acid bacteriarepresentative was analysised combined with molecular biology for Gansu provice traditionalvinegar brewing mass and screened the excellent acetic acid bacteria, which lay thefoundation for the further development and utilization of acetic acid bacteria. Aim to providea theory basis and reference for the modernization and technological upgrading of traditionalvinegar brewing process. The main conclusions obtained as follows:(1)The15samples of vinegar brewing mass were separated from the threerepresentative regions of Gansu as material. Using the method of Calcium carbonatetransparent circle screened175acid-producing strains and rescreened150acetic acidbacterias by morphological observation and qualitative test of acetic acid bacterias. Thenthrough the method of the classic microbial identification, co mbined with the sequence of16SrRNA, identified the acid-producing bacteria. The identification results showed that it had104strains Acetobacter, which included54strains belonged to Acetobacter pomorum,31strainsbelonged to Acetobacter pasteurianus,19strains belonged to Acetobacter pasteurianus subsppasteurianus and37strains belonged to Gluconobacter, which included25strainsGluconobacter oxydans,12strains Gluconobacter albidus,7strains Bacillus,2strainsStaphylococcu epidermidis,25strains Lactobacillus in the150strains of reddish-brownprecipitate of producte acetate qualitative test.(2)The diversityof acetic acid bacteria was analysised byMargalef richness index, thePielou uniform index (Jsw) and Shannon-Wiener diversity index in the geographical area ofthree traditional vinegar brewing masses in Gansu province. Margalef richness index of aceticacid bacteria was highest in the mass of Hexi area. The species richness of acetic acid bacteriawas better in the traditional brewing process, and the Shannon-Wiener diversity index wasbiggest in there. The result showed that the diversity of hexi area was higher than central andsoutheastern in Gansu province.(3)This study indicated Acetobacter pomorum was the dominant acetic acid bacteria ofthe tradition brewing process in Gansu province. And the producted acid quality of A3wasexcellent strains in the bacteria species. The content of producted acid reached3.9089g/100mL in fermentation conditions of the initial ethanol concentration4.0%, thefermentation temperature30°C, pH6.0, the fermentation time8d. This strain in the vinegar brewing industrial production in China had not see the relevant reports. This result belongedto the first time and it was a new resource of germplsm for the fermentation of acetic acid.(4)Optimized fermentationconditions ofacetic acid bacteria A3strains by orthogonalexperiment and artificial neural network model. The optimum fermentation conditions wereinitial ethanol concentration4.2%(v/v), fermentation temperature30°C, initial pH6.4,fermentation time8d. The content of simulation production acid reached highest,4.3234g/100mL for BP network model and the content of test production acid was4.3086g/100mLunder this condition.