高产透明质酸兽疫链球菌的诱变选育与发酵优化及代谢组学分析OA

In order to enhance hyaluronic acid yield of Streptococcus zooepidemicus and investigate its meta-bolic mechanisms under varying fermentation conditions,S.zooepidemicus ATCC 39920 was subjected to compound mutagenesis using ultraviolet and diethyl sulfate to screen a high-yield hyaluronic acid mutant strain SQ49,its fermentation conditions in 5 L bioreactors were optimized,and the intracellular differential metabo-lites under varying temperature and initial glucose concentration conditions were analyzed using metabolomics.The results showed that the hyaluronic acid yield of SQ49 reached 1.05 g·L-1,2.83 times higher than that of its parent strain.Under the optimal fermentation conditions(ventilation capacity of 12 L·min-1,agitation speed of 600 r·min-1,pH value at 7.5,initial glucose mass concentration of 60 g·L-1,and temperature at 37℃),the hyaluronic acid yield of SQ49 was increased to 6.61 g·L-1.Metabolomics results showed that the accumulation of DL-leucyl-valine was a key temperature-controlled target driving high hyaluronic acid yield,and accumulating palmitic acid and inhibiting lactic acid accumulation were key carbon source-controlled targets for enhancing hyaluronic acid yield.