四株酵母乙醇发酵的初步研究

Preliminary Study on Ethanol Fermentation by Four Strains

比较了休哈塔假丝酵母NLP21、树干毕赤酵母NLP22、NLP23和NLP31,在30g/L的木糖和混合糖(葡萄糖15g/L+木糖15g/L)发酵培养基上以及在培养基中氮源浓度降低到原来1/2和1/10时的发酵性能。结果表明,在30g/L木糖发酵培养基上,NLP23和NLP31产乙醇质量浓度最高,分别为(11.14±0.13)和(11.15±0.08)g/L。在15g/L葡萄糖+15g/L木糖混合糖发酵培养基上,NLP31产乙醇质量浓度最高,为(10.91±0.12)g/L。当发酵培养基中氮源浓度降低到原来的1/2时,NLP23和NLP31产乙醇能力相当,但后者产木糖醇的量增大;当氮源质量浓度降低到原来的1/10时,NLP23和NLP31产乙醇能力随着发酵轮数的增加,逐渐下降,氮源浓度低,降低了乙醇的产量。

Fermentabilities of four strains, Candida shehatae NLP21, Pichia stipitis NLP22, NLP23 and NLP31 on 30 g/L xylose or mixture sugars （glucose 15 g/L and xylose 15 g/L） of the fermentation medium, and on the fermentation medium of the concentrations of the nitrogen sources reduced to 1/2 and 1/10 of its original were studied. The results showed that the mass concentrations of ethanol produced by NLP23 and NLP31 were the highest, （11. 14 -＋ O. 13 ） and （11. 15 ± 0. 08）g/L respectively, when they were fermented on the fermentation medium with 30 g/L xylose. When four strains fermented on the fermentation medium with 15 g/L glucose and 15 g/L xylose, the mass concentration of ethanol produced by NLP31 was the highest, （10.91 ±0.12） g/L. The fermentability of NLP23 was the same as NLP31 when the concentration of nitrogen sources was reduced to 1/2 of its original, but NLP31 produced more xylitol. The fermentabilities decreased step by step with the fermentation batch increasing when the mass concentration of nitrogen sources was reduced to 1/10 of its original, because the mass concentration of the nitrogen source was too low.