发酵蔗渣糖化液产乙醇菌株的选育

Abstract

利用纤维生物质生产生物燃料是解决当今世界能源和环境问题的重要途径.本研究从腐烂蔗渣、酒曲、酒糟等样品中分离到一批产乙醇菌株,通过高浓度乙醇选择性培养基筛选、TTC法复筛以及发酵乙醇能力分析,筛选得到一株发酵蔗渣糖化液能力较强的菌株.通过对菌落形态观察、电镜图片分析、18S rDNA基因序列分析,确定该菌株属于酿酒酵母属,命名为Saccharomyces cerevisiaeQ2-1.优化了S.cerevisiaeQ2-1发酵蔗渣糖化液产乙醇条件,当起始pH为5.5、发酵温度为30℃、糖化液中硫酸铵浓度为0.4%时,静置发酵60 h后,发酵率可达89.2%,蔗渣产乙醇率ω=13.6%.

Several strains ferment ethanol using bagasse saccharification mixture were isolated from rotted bagasse and lees.The strain with highest ethanol yield was screened and identified as Saccharomyces cerevisiae Q2-1 by analysis of morphology and 18S rDNA sequences.The optimum conditions for ethanol production using bagasse saccharification mixture were obtained as: using 0.4 %(NH4)2SO4 as nitrogen source,fermentation temperature 30℃,pH 5.5,fermentation time 60 h.The maximum zymolysis ratio was achieved as 89.2% with an ethanol yield of 13.6%(by mass).