土壤中产木糖醇酵母菌株的筛选其发酵条件优化

本文以木糖为唯一碳源从土壤中筛选得到可以耐受高浓度木糖的菌株,再经过复筛选出一株高产木糖醇的酵母菌株Y-9。经高效液相色谱(HPLC)和红外扫描分析,确定菌株Y-9发酵利用木糖转化得到的主要产物为木糖醇。通过单因素实验、正交试验等手段,对菌株Y-9发酵产木糖醇的培养基组分和发酵条件进行了优化,进一步提高了目的菌株的木糖醇产率和转化率,确定了菌株Y-9摇瓶发酵木糖转化木糖醇的最优培养基和发酵条件。在木糖初始浓度为200 g/L,氮源为酵母膏3.0 g/L,硫酸铵2.0 g/L,玉米浆10.0 mL/L,硫酸镁0.1 g/L,初始pH为6.0,转速为180 r/min,接种量为4%的条件下,菌株Y-9的木糖醇产率为160 g/L左右,木糖醇生成速率为1.67 g/L.h,木糖/木糖醇转化率达到80%以上,是一株具有良好工业化研究开发价值的木糖醇生产菌株。

Screening of Xylitol-producing Yeast Strains from Soil and Optimization of the Fermentation Conditions

A yeast strain Y-9 was isolated from soil samples, which could tolerate high concentrations of xylose. HPLC and infrared scanning analysis showed that the main product of the strain Y-9 was xylitol. To improve the xylitol production and conversion rate of strain Y-9, the medium compositions and cultural conditions were optimized by means of single factor experiment and orthogonal tes. Under the optimal cultural conditions (initial xylose concentration 200 g/L, yeast extract 3 g/L, ammonium sulfate 2 g/L, corn steep liquor 10 mL/L, magnesium sulphate 0.2 g/L, initial pH 6, rotation speed 180 r/min and inoculum size 4%), The yield and producing rate of xylitol reached 160 g/L and 1.67 g/L?h, respectively. The conversion rate of xylose reached 80%.