产酒精热带假丝酵母突变株的五、六碳糖共代谢分析

Co-metabolism Analysis of Pentose and Hexose in Candida tropicalis Mutants

生物质水解产物五碳糖的利用一直是个难题,提高五碳糖的利用率既能减少木质纤维素的浪费,又能提高乙醇产量。本实验对热假丝酵母进行紫外诱变,通过杜氏小管法和TTC显色法获得一株能利用木糖的突变菌株,并对其进行发酵实验,测定发酵情况以及对五、六碳糖共发酵效率;进而对其发酵机理进行探讨,构建酵母菌代谢网络并建立方程,进行矩阵计算得到细胞的代谢通量。结果表明,原始菌和突变株对葡萄糖的利用情况均较好,利用率分别接近95%、96%;但原始菌木糖的利用率低,乙醇产量最终只有17.58 g/L;而突变株T70-2的乙醇产量达到22.85 g/L,木糖的利用率可达92.2%。因此,本研究所得突变菌株能够实现五、六碳糖的共发酵。

The use of biomass hydrolysate,pentose,has always been a difficult problem.Increasing the utilization of pentose can reduce the waste of lignocellulose and increase ethanol production.In this paper,a mutant strain of Candida tropicalis bred by UV mutagenesis capable of utilizing xylose was obtained by Dux tube method and TTC chromogenic method,and fermentation experiments were carried out to determine the fermentation and the efficiency of co-fermentation of hexose and pentose.Then,the fermentation mechanism was discussed through metabolic network and metabolic equations and mathematical matrix.The results showed that,the utilization of glucose by the original and mutant strains was good,and the utilization rates were close to 95%and 96%,respectively.However,the utilization rate of the original strain xylose was low,and the ethanol yield was only 17.58 g/L.The ethanol yield of the mutant strain T70-2 was 22.85 g/L,and the utilization rate of xylose was 92.2%.Therefore,the mutant strain obtained in this study was capable of achieving co-fermentation of pentose and xylose.