不同凝结芽孢杆菌在单一及混合碳源下的发酵特性

Fermentation Characteristics of Different Strains of Bacillus coagulans with Single and Mixed Carbon Sources

本文研究了凝结芽孢杆菌BH1、HL5和36D1在木糖、海藻糖、葡萄糖、低聚异麦芽糖、蔗糖和麦芽糖等单一碳源和葡萄糖分别加其他五种碳源(即混合碳源)下的底物利用和代谢情况,对三株菌以葡萄糖和低聚异麦芽糖作为混合碳源进行5 L罐发酵,进一步考察三株菌发酵特性,以期确定一株菌株作为后续高效乳酸发酵菌株筛选的出发菌株。结果显示:单一碳源发酵下,凝结芽孢杆菌36D1可以完全利用海藻糖、木糖和葡萄糖,而BH1和HL5对木糖和海藻糖几乎无利用,同时三株菌对蔗糖均无明显利用;混合碳源发酵下,凝结芽孢杆菌36D1发酵过程中表现出明显的葡萄糖阻遏效应,BH1和HL5对其他糖(尤其是麦芽糖和异麦芽糖)的利用几乎不受影响;5 L罐发酵结果表明,HL5对异麦芽糖的利用能力较优。凝结芽孢杆菌HL5对麦芽糖、异麦芽糖以及葡萄糖的利用能力较高,最终确定HL5作为后续菌株筛选的出发菌株。

The substrate utilization and metabolism of Bacillus coagulans BH1,HL5 and 36 D1 by using various substrates as sole carbon sources,including xylose,trehalose,glucose,isomaltose,sucrose and maltose,and glucose with five above carbon sources as mixed carbon sources were studied. Then,the fermentation characteristics for the three strains in a 5 L tank using glucose and isomaltose as a mixed carbon source were inspected. The fermentation characteristics of the three strains were further investigated in order to determine one strain as the starting strain for subsequent screening of high-efficiency lactic acid fermentation strains. Results showed that that:Under single carbon source fermentation,B.coagulans 36 D1 could fully utilize xylose,trehalose and glucose,while BH1 and HL5 had almost no use of xylose and trehalose,and all three strains had no obvious use of sucrose. Under mixed carbon source fermentation,B. coagulans 36 D1 exhibited the obvious glucose repressive effect in the fermentation process,and the use of other sugars(especially maltose or isomaltose)by BH1 and HL5 was hardly affected. The results of 5 L tank fermentation showed that B. coagulans HL5 had better utilization of isomaltose. In conclusion,B. coagulans HL5 had a high utilization capacity for maltose,isomaltose and glucose,and would be finalized as the starting strain for subsequent strain screening.