Study On Screening And Fermentation Application Of Acetic Acid Bacteria In Brewing Process Of Shanxi Aged Vinegar

In this experiment,used microbiology culture method to separate the acetic acid bacteria in the different stages of Shanxi aged vinegar fermentation process,the physiological and biochemical and 16S rDNA methods to identify the acetic acid bacteria in the whole fermentation process,than select the strains that were able to tolerate the high acidity,high alcohol and high temperature of the vinegar,and verified the excellent strains.The test results are as follows:(1)Isolated and identified the acetic acid bacteria from the Shanxi aged vinegar fermentation process,obtained that the 63 strains of acetic acid bacteria were A.pasteurianus;4 strains of acetic acid bacteria were A.actei;12 strains of acetic acid bacteria were A.Liquefaciens;6 strains of acetic acid bacteria were A.rancens Beijerinck;13 strains of acetic acid bacteria were A.hansenii.The fermentation stage of the wine,acetic acid bacteria were A.pasteurianus,A.Liquefaciens and A.hansenii.At the beginning of the vinegar fermentation,the mainly strain was A.pasteurianus,and some A.Liquefaciens,A.hansenii and A.actei,with the fermentation of vinegar the A.rancens Beijerinck was appeared.(2)The trend of acetic acid bacteria in the brewing process of Shanxi aged vinegar was that the fermentation stage of the wine,the number of acetic acid bacteria on day 2 was 6.9x 106 cfu/mL,and then showed a declining trend,finally the acetic acid bacteria almost exhausted;at he vinegar fermentation stage,with the "ferrous grain" access,the number of acetic acid bacteria increased first and then decreased,the number of acetic acid bacteria was 1.4x 104 cfu/mL on the 2nd day after the "fermented grains",In the third day of vinegar reached a peak 2×107 cfu/mL,And then began to decline,in the fermentation of the first 8 d down to 2.1×104 cfu/mL.(3)The strains A3-37,A8-12,A8-9',A3-32,A3-28,A3-7,A3-8,F9',A3-22,A8-9,A3-26 acid production capacity were better,and study these strains resistance in high temperature,alcohol and acid,final find that strain A3-7 has a good tolerance,and in the 12%alcohol environment,the strain acid production is better,up to 1.889g/100ml,Can better adapt to Shanxi aged vinegar fermentation process.(3)The strains A3-7 were tested for acetic acid.The 2%(L/kg)inoculated into vinegar grains to strengthen the vinegarization process of Shanxi aged vinegar,use the bacteria fermentation liquid which density was 106-107 cfu/mL.The results showed that the total content of acid was 5.5 g/100ml,which was significantly higher than that of the control(4.1 g/100ml);the total content of the ester was 3.91 g/100ml,which was significantly higher than that of the control group(3.21 g/100ml);the non-volatile acid was 1.43 g/100ml,which was significantly higher than that of the control group(1.10 g/100m);Although the other indicators to strengthen the group although the improvement did not reach a significant level.