影响产土味素链霉菌生长及代谢的白酒酿造相关环境因素

摘要

Geosmin-producing Streptomyces may cause the imbalance ofmicrobial flora seriously deterioratthe liquor aroma.The aim of this study is to identify the key factors restricting geosmin production in the liquor-making process.The influence of the main liquor-makingvariables (temperature,water content,ethanol content,pH) on the growth and metabolism of geosmin-producing Streptomyces were investigated.The results showedthat the yield of geosmin was positivelyrelated with the biomass and growth rate of the Streptomyces cells.The most suitable temperature for thegrowth of Streptomyces was 30℃,andthe optimum water content was 50％.The growth of geosmin-producing Streptomyces iscompletely inhibited at the alcohol content of over 10％ vol.Moreover,Streptomycescan grow rapidly in the neutral and alkalescent (pH7-8) environment,whileit is severelyinhibited in the acidic environment(pH3-5) reduce geosmin production.The above discoveries provide reliable theory to control the earthy off-flavor in Chinese liquor.%产土味素(geosmin)的链霉菌对白酒酿造菌群及风味造成严重影响.该研究目的是发现白酒酿造中限制土味素生物合成的特征环境因子.针对白酒群体微生物固态酿造体系的特征,系统地研究了酿造环境因素(温度、水分、乙醇含量、pH等)对产土味素链霉菌生长及代谢的影响规律.研究发现土味素的产量与菌体的生物量和生长速率是呈正相关的关系.发现产土味素链霉菌最适生长温度为30℃,最适生长的基质含水量为50％.乙醇体积分数高于10％的酿造环境中,产土味素链霉菌菌体生长会受到完全抑制.菌体在中性偏碱性(pH7～8)的环境中可以大量繁殖.在酸性(pH3～5)环境中,产土味素链霉菌菌体生长受到抑制,并进而减少土味素的产生.研究结果对有效控制白酒中土霉异味提供了可靠的理论依据.