己酸菌对高产酯酿酒酵母酒精发酵及酯醇代谢的影响

Effects of Caproic Acid Bacteria on Alcohol Fermentation and Ester-Alcohol Metabolism of Saccharomyces cerevisiae with High-yield Ester

将己酸菌与高产酯酿酒酵母在高粱汁培养基中进行混合发酵,研究己酸菌对高产酯酿酒酵母酒精发酵及酯醇代谢的影响。结果表明,己酸菌菌悬液对高产酯酿酒酵母的生长及代谢没有直接影响;己酸菌的代谢产物对高产酯酿酒酵母的发酵速度及酒精产量有所促进,在培养基己酸浓度为220mg/L时,酒精产量提高了6.63%;在己酸浓度为45~220mg/L时,高产酯酿酒酵母的乙酸酯类和主要高级醇受到的抑制作用逐渐增强,乙酸乙酯最多降低65.32%,乙酸异丁酯最多降低91.32%,乙酸异戊酯最多降低82.14%,高级醇最多降低71.14%;在己酸浓度为220mg/L时,与己酸浓度为0mg/L时对比,高产酯酿酒酵母共有1032个基因转录水平上调,有1037个基因转录水平下调,这些转录水平变化的基因主要涉及到高产酯酿酒酵母的氮代谢、糖酵解、苯丙氨酸代谢、碳代谢等多条代谢途径。

Caproic acid bacteria and Saccharomyces cerevisiae with high-yield ester are mixed and fermented in sorghum juice medium to study the effects of caproic acid bacteria on alcohol fermentation and ester-alcohol metabolism of Saccharomyces cerevisiae with high-yield ester.The results show that caproic acid bacteria suspension has no direct effect on the growth and metabolism of Saccharomyces cerevisiae with high-yield ester;the metabolites of caproic acid bacteria promote the fermentation speed and ethanol production of Saccharomyces cerevisiae with high-yield ester.When the concentration of caproic acid is 220 mg/L,the ethanol production is increased by 6.63%.When the concentration of caproic acid is 45~220 mg/L,the inhibition of acetic esters and main higher alcohols of Saccharomyces cerevisiae with high-yield ester is gradually enhanced,and ethyl acetate is decreased by 65.32%at most,isobutyl acetate is decreased by 91.32%at most,isoamyl acetate is decreased by82.14%and higher alcohols are decreased by 71.14%at most.When caproic acid concentration is 220 mg/L,there are 1032 gene transcription levels up regulated and there are 1037 gene transcription levels down regulated in Saccharomyces cerevisiae with high-yield ester compared with that without caproic acid,which involve many metabolic pathways such as nitrogen metabolism,glycolysis,phenylalanine metabolism and carbon metabolism of Saccharomyces cerevisiae with high-yield ester.