一株芽孢杆菌在维生素C二步发酵中对小菌的促进作用

从土壤中分离到1株能更好促使小菌生长和产酸的芽孢杆菌B601，作为伴生菌与巨大芽孢杆菌相比，在生长过程中，发酵液中B601活菌数小于巨大芽孢杆菌，而其芽孢数则多于巨大芽孢杆菌。对B601组成菌系的发酵条件进行优化，得到如下结果：100g／L L-山梨糖、6g／L尿素、10g/L玉米浆、培养温度30℃和发酵周期44h。与巨大芽孢杆菌组成菌系相比其底物，L-山梨糖质量浓度提高了25％，尿素下降了50％．玉米浆质量浓度下降了33％，温度提高了2℃，发酵周期缩短了4h。结果表明：B601作为伴生菌，与巨大芽孢杆菌相比，该菌株明显提高了发酵效率。

Promotion effect of Bacillus megaterium on Ketogulonigenium vulgare in two-step fermentation of vitamin C

A strain of Bacillus megaterium B601, in possession of promotion effect on Ketogulonigenium vulgare growth and acid production, was screened from soil. Under mixed fermentation conditions, the number of the viable bacterium was less than that of B. megaterium, but the number of the spores was more than that of B. megaterium. The conditions for the fermentation associated B601 were optimized as follows：L-sorbose 10%, urea 0.6%, corn steep liquor 1.0%, culture temperature 30 ℃, pH 6. 8, and fermentation time 44 h. Compared with the control fermentation, L-sorbose production was enhanced by 25% , the urea consumption and the corn steep liquor were decreased by 50% and 33% , respectively, the culture temperature was increased by 2 ℃, and the fermentation time was reduced by 4 h. The efficiency of fermentation was improved using B601 associated bacteria.