粗糙脉孢菌(Neurospora crassa)木糖发酵的研究

Study on Xylose Fermentation by Neurospora crassa

研究了不同通氧条件和培养基初始pH等对粗糙脉孢菌 (Neurosporacrassa)AS 3 1 60 2木糖发酵的影响。结果表明 ,粗糙脉孢菌具有较强的发酵木糖产生乙醇及木糖醇的能力。通气量对木糖发酵有较大的影响。乙醇发酵适合在半好氧条件下进行 ,此时乙醇的转化率达到63 2 %。木糖醇发酵适合在微好氧的条件下进行 ,转化率达到 31 8%。木糖醇是在培养基中乙醇达到一定浓度后才开始积累。培养基的初始pH对木糖发酵产物有较大的影响 ,乙醇产生最适pH5 0 ,木糖醇产生最适pH4 0。在培养基pH为碱性条件时 ,木糖发酵受到很大的抑制。初始木糖浓度对产物乙醇及木糖醇的产率有很大的影响。葡萄糖的存在会抑制木糖的利用 ,对乙醇和木糖醇的产生也有很大的影响。

The influence of oxygen limitation and medium initial pH on xylose fermentation by Neurospora crassa AS 3.1602 was investigated. N. crassa AS 3.1602 has high ability of xylose fermentation producing ethanol and xylitol. Oxygen limitation has big influence on ethanol and xylitol production .The maximum conversion rate of ethanol was 63.2% obtained under semi-aerobic conditions. The maximum conversion rate of xylitol was 31.8% obtained under micro-aerobic conditions. Xylitol accumulation is behind the accumulation of ethanol. The optimal pH is 5.0 for ethanol fermentation, and 4.0 for xylitol fermentation, respectively. Xylose fermentation is greatly inhibited at high pH. The yields of ethanol and xylitol are greatly influenced by the initial concentration of xylose. The addition of glucose inhibits both the xylose utilization and the ethanol and xylitol production.