嗜鞣管囊酵母木糖发酵乙醇高产突变株选育及其发酵特性

BREEDING AND FERMENTATION CHARACTERIZATION OF Pachysolen Tannophilus MUTANT WITH HIGH ETHANOL PRODUCTIVITY FROM XYLOSE

目前能够利用木糖发酵产乙醇的菌株很少且产量较低,对菌株进行诱变选育,可以提高其对木质纤维素的利用率。本试验选择嗜鞣管囊酵母As2.1585为原始菌株,采用15keV的低能氮离子进行注入诱变。随着注量的增加,菌体存活率曲线呈"马鞍型",综合考虑其存活率和正突变率,确定最佳诱变注量为12.5×1014ions/cm2,对诱变后菌体进行筛选,获得了嗜鞣管囊酵母高产菌株mut-54,传代7次后乙醇产量稳定。试验表明,突变株mut-54对木糖的利用速率、生物量积累以及耐酒精能力均高于原始菌株,发酵72 h乙醇产量较原始菌株提高12.74%。突变株mut-54比原始菌株更适合用于木糖发酵产乙醇。

Currently,few strains can utilize xylose to produce ethanol with very low productivity.By the method of mutation breeding to these strains the rate of lignocellulosic utilization could be improved.In this study,the initial Pachysolen tannophilus As2.1585 was treated by N ＋ ions implantation of 15keV.The survival curve showed a saddle model.Considering the survival rate and range of positive mutation,the N ＋ ions implantation of 12.5 × 1014ions /cm2 for mutation breeding of Pachysolen tannophilus was selected.A Pachysolen tannophilus mutant mut-54,which had perfect genetic stability of producing ethanol was screened out after continuous 7 passages.The mut-54 had a higher xylose consumption rate,biomass accumulation and ability of ethanol-resistant than the parent strain.Compared with the parent strain,the ethanol concentration fermented by the mut-54 for 72h increased by 12.74 %,which was more suitable for producing ethanol from xylose than the parent strain.