发酵木糖高产乙醇休哈塔假丝酵母突变株的选育

木糖的乙醇发酵是利用木质纤维原料生产乙醇的关键环节。休哈塔假丝酵母是木糖发酵性能较好的天然酵母之一。研究中对Candida shehatae CICC1766进行了紫外诱变和离子注入诱变,力求选育出发酵木糖产乙醇能力强的假丝酵母。先将其进行紫外诱变,得到的突变株S28在木糖添加量为60g/L的条件下乙醇产量为2364g/L,相比原始菌株提高1498%,乙醇得率达到0394g/g(乙醇/木糖)。再对S28进行氮离子注入诱变,得到的突变株SY58乙醇产量为2508g/L,相比S28提高609%,乙醇得率为0418g/g(乙醇/木糖),达到理论得率的908%。进而对SY58菌株进行了5L罐发酵实验,乙醇产量达到2504g/L,得率为0417g/g(乙醇/木糖),同摇瓶发酵结果基本相同,并且发酵时间由原来的72h缩短到52h。

Breeding of Candida shehatae Mutant Overproducing Ethanol from Xylose

Xylose fermentation is one of the technical barriers to lignocellulosic materials bioconversion into ethanol.Candida shehatae is one of the best xylose-fermenting yeast in nature.In this paper,C.shehatae CICC 1766 was mutagenized with ultraviolet radiation and N ion implantation to select the mutants with better xylose fermentation performance.After UV mutagenesis,a mutant S28 which could produce 23.64 g/L ethanol from 60 g/L xylose was obtained.The ethanol concentration was increased by 14.98% compared with original strain C.shehatae CICC 1766 and the ethanol yield reached 0.394g/g(ethanol/xylose).After N ion implantation,a high-yield mutant SY58 was screened out,which could produce 25.08g/L ethanol from 60g/L xylose.The ethanol concentration was increased by 6.09% compared with S28.The ethanol yield reached 0.418g/g(ethanol/xylose),which is 90.8% of theoretical yield.The xylose fermentation ability of SY58 was further tested in 5L fermentor.At the end of fermentation,the ethanol concentration was 25.04g/L,and the ethanol yield reached 0.417g/g(ethanol/xylose),which were equal to that in flask scale fermentation.The fermentation period was shortened from 72 hours to 52 hours.