玉米芯水解液发酵生产木糖醇的研究

STUDIES ON XYLITOL FERMENTATION OF CORN COBS HYDROLYSATE BY CANDIDA SP.

假丝酵母 (Candidasp .)菌株经驯化后显著地提高了对水解液中发酵抑制物质的耐受力 ,从而增加了木糖利用率和木糖醇得率。玉米芯水解液经过石灰中和后 ,在 30℃下采用驯化后的假丝酵母菌株直接发酵生产木糖醇。对发酵条件进行了优化 ,优化结果为 :接种量 1 0 % (体积比 ) ,种子龄 1 7h,氮源组成 :1 .5g/L的酵母浸膏 ,2 .5 g/L的胰蛋白胨 ,2 5 0mL三角瓶装液 1 2 0mL ,初始pH值 5 .5。在此条件下 ,木糖的利用率达 79.8% ,木糖醇得率达 6 2 .4 %。该方法大大降低了预处理的成本 。

The adaptation of Candida sp.can effectively enhance its resistance to the inhibitors in the hydrolysate of corn cobs,and therefore improves the xylose utilization efficiency and xylitol yield.At 30 ℃,hydrolysate produced by dilute acid pretreatment can be directly fermented after simply treated by Ca(OH) 2 using the adapted yeast strain.The optimum fermentation conditions were as follows:inoculum size 10%(volume ratio),inoculum age 17 h,nitrogen source 1.5 g/L Bacto-yeast extract and 2.5 g/L Bacto-tryptone,volume charge 120 mL in 250 mL flasks,intitial pH value 5.5.Xylose utilization efficiency over 79.8% and xylitol yield higher than 62.4% were obtained respectively.This process can effectively reduce the pretreatment costs,showing broad prospects of applications.