驯化树干毕赤酵母发酵产乙醇的研究

以玉米秸秆蒸汽爆破液为底物培养基，通过逐步提浓的方式对树干毕赤酵母菌株（Pichiastipitis）NLP23进行耐抑制物驯化，驯化后的菌株对汽爆液中甲酸和乙酸等抑制物的耐受能力可分别达到2．70g／L和3．54g／L，较出发菌株分别提高253．40％和277．80％。在含有57．34g/L木糖和13．84g／L葡萄糖的汽爆液中发酵42h，糖利用率和乙醇得率可达到97．89％和65．83％，乙醇质量浓度为21．56g/L，同时生成4．16g/l木糖醇。玉米秸秆蒸汽爆破液中含有多种抑制酵母生长和发酵的有毒物质，主要是甲酸、乙酸、乙酰丙酸、糠醛和羟甲基糠醛，其中甲酸和乙酸含量较高，是影响树干毕赤酵母NLP23发酵汽爆液的主要抑制物。

The Study of Ethanol Produclion by the Adapted Pichia stipitis

Corn stalks steam explosion of liquid has been utilized as a substrate for ethanol production using Pichia stipitis NLP23. Adaptation of the yeast was performed by sequentially transferring and growing cells in media containing increasing concentrations of Corn stalks steam explosion of liquid. The subculturing was carried out several times to obtain adapted strain. The adapted strain is finally able to tolerate higher inhibitor concentration, such as formic acid and acetic acid inhibitor-resistant ability can be reach 2.70 g/L and 3.54 g/L simultaneously, higher than the starting strain 277.80% and 253.40% separate. Main in the culture medium containing glucose 13.84 g/L, D-xylose 57.34 g/L, when, after 42 h fermentation, sugar utilization and ethanol yield can reach 97.89% and 65.83% respectively, while generating xylitol 4.16 g/L and ethanol 21.56 g/L respectively in fermentation broth. Corn stalks steam explosion fluid contains a number toxic substances which inhibit the growth and fermentation of yeast, mainly formic acid, acetic acid, levulinic acid, furfural and hydroxymethyl furfural, in which formic acid and acetic acid are the main inhibitors impact on fermentation of yeast E stipitisNLP23 because of their higher levels.