利用核糖体工程选育丙酮丁醇菌提高丁醇产量

Screening of Clostridium strains through ribosome engineering for improved butanol production

摘要:

利用核糖体工程技术对丙酮丁醇梭菌Clostridium acetobutylicum L7进行诱变筛选，以获得丁醇高产菌株。使用链霉素诱变C. acetobutylicum L7并结合设计的平板转接逐次提高链霉素浓度的筛选路线，获得丁醇产量较高的菌株S3。结果表明，S3丁醇产量为 (12.48±0.03) g/L，乙醇产量为 (1.70±0.07) g/L，相对于原始菌分别提高了11.2%及50%；丁醇/葡萄糖转化率由原始菌的0.19提高到0.22，丁醇生产率达到0.24 g/(L?h)，相比提高30.5%；耐受丁醇浓度由原始菌的12 g/L提高到14 g/L；发酵液粘度下降到4 mPa/s，同比降低了60%，利于后续分离工作的进行，降低发酵成本。进一步研究工作表明，S3菌株遗传稳定性良好。因此，核糖体工程技术是一种选育丁醇高产菌株的有效方法。

Abstract:

We used ribosome engineering technology, with which antibiotic-resistant strains are resulted from mutations on microbial ribosome, to screen a high butanol-producing Clostridium strain. A novel mutant strain S3 with high butanol production and tolerance was obtained from the original Clostridium acetobutylicum L7 with the presence of mutagen of streptomycin. Butanol of 12.48 g/L and ethanol of 1.70 g/L were achieved in S3, 11.2% and 50%, respectively higher than the parent strain. The conversion rate of glucose to butanol increased from 0.19 to 0.22, and fermentation time was 9 h shorter. This caused an increase in butanol productivity by 30.5%, reaching 0.24 g/(L?h). The mutant butanol tolerance was increased from 12 g/L to 14 g/L, the viscosity of fermentation broth was dramatically decreased to 4 mPa/s, 60% lower than the parent strain. In addition, the genetic stability of mutant strain S3 was also favorable. These results demonstrate that ribosome engineering technology may be a promising process for developing high butanol-producing strains.