凝结芽孢杆菌的筛选及发酵特性的研究

Screening and fermentation characteristics of Bacillus coagulans

本研究探讨了六株凝结芽孢杆菌耐高温和高效利用玉米粉生产L-乳酸的特性。首先通过平板初筛后,获得了HL1、HL3、HL4、HL5四株菌。然后进行50、53、55℃发酵培养,结果表明HL5的温度耐受性更强。再以玉米粉糖化液为底物进行5L罐50℃分批发酵,发现HL5的L-乳酸产量、产率以及转化率均最高,分别为115g/L、3.59g/L/h、100.1%。基于上述结果,选择HL5作为适合的耐高温L-乳酸生产菌株。最后本文考察了HL5对玉米粉、木薯粉和纤维素来源糖化液的利用情况,它们的产酸速率分别为4.19、3.75、5.00g/L/h,说明HL5对三种来源糖类均能利用。因此,HL5为乳酸的工业生产提供了菌种基础。

Six strains of Bacillus coagulan were studied for their ability of thermotolerant and production of lactic acid with corn meal.Four strains of B.coagulan （ HL1, HL3, HL4, HLf） had been screened from plate culture.Then they were cultured at 50,53 and 55℃ respectively, the results showed that HL5 was more thermotolerant. In 5L batch fermentation with corn saccharification liquid as carbon source at 50℃, HL5 had the highest L-lactic acid production, productivity and yield, which were 115 g/L,3.59g/L/h, and 100. 1 %, respectively.At last, comparisions of L-lactic acid production with corn meal,cassava flour and cellulose as carbon sources were carried out, and the productivity were 4.19g/L/h,3.75g/L/h,5.00g/L/h respectively, indicating these carbon sources could be utilized by HL5.Therefore HL5 is qualified as a potential industry lactic acid producer.