外加肌醇和氯化钠对嗜鞣管囊酵母生长和产酒精能力及耐酒精能力的影响

Effects of Inositol Addition and Sodium Chloride on Cell Viability, Ethanol Production and Ethanol Tolerance of Pachysolen tannophilus

嗜鞣管囊酵母(Pachysolen tannophilus)是可以同时发酵葡萄糖和木糖为酒精的菌种,在其培养基中分别添加不同浓度的(0￣0.2g·L-1)肌醇和(0￣1.5g·L-1)NaCl,以考察它们对嗜鞣管囊酵母生长、产酒精能力和耐酒精能力的影响。结果表明,外加肌醇和NaCl对嗜鞣管囊酵母生长有轻微的刺激作用,而对酵母生长的耐酒精能力却有明显的影响,并且,菌种在YEPD培养基中的耐酒精能力高于在YEPX培养基中的耐酒精能力。经实验测定,肌醇和NaCl对嗜鞣管囊酵母产酒精能力及发酵的耐酒精能力均有显著的影响。当发酵培养基中未添加酒精,肌醇和NaCl浓度各为0.1g·L-1和1.5g·L-1时,可以分别达到的最高酒精产量为45.20g·L-1和40.12g·L-1。在发酵过程中,当酒精起始浓度分别为10%和12%时,随肌醇浓度的增加,酒精的净生成量呈上升趋势,最高分别为17.18g·L-1和16.68g·L-1;添加NaCl后,酒精的净生成量亦呈现相同的规律,最高可达10.16g·L-1和9.87g·L-1。

Glucose and xylose could be fermented by Pachysolen tannophilus simultaneously. In order to investigate the effects of added inositol and NaCl on cell viability, ethanol production and ethanol tolerance of Pachysolen tan nophilus, different concentrations of inositol（0-0.2 g·L^-1）or NaCl （0-1.5 gC·L^-1）were added respectively in the media. Both of inositol and NaCl could protect yeast cell from harmful effect of high concentration ethanol. The results indicated that inositol and NaCl had remarkable effects on ethanol production and ethanol tolerance, but little on the growth of Pachysolen tannophilus. Furthermore, ethanol tolerance was more powerful when the yeast was cultured in YEPD medium than in YEPX medium. It was found that, there were more yeast biomass and more ethanol production in the presence of inositol and NaCl than without them. With the addtion of initial ethanol, the most appropriate concentrations of inositol and NaCl for yeast fermentation were 0.1 g·L^-1 and 1.5 g·L^-1, while the ethanol production yield were 45.20 g·L^-1 and 40.12 g·L^-1, respectively. The more added inositol and NaCl, the more ethanol was produced when the fermentation medium contained 10% or 12% initial ethanol. The maximum ethanol concentrations were 17.18 g·L^-1 and 16.68 g·L^-1 fermented by inositol addition, and 10.16 g·L^-1 and 9.87 g·L^-1 by NaCl addition with the same formula. It is revealed that inositol plays a more important role in ethanol production and ethanol tolerance than NaCl.