巨大芽胞杆菌的产酶特性及发酵条件的研究

Enzyme Production Characteristics & Fermentation Conditions of Bacillus megaterium

对1株巨大芽胞杆菌JSSW-JD的产胞外酶特性及发酵条件进行了研究。结果显示:巨大芽胞杆菌JSSW-JD具有较强的产胞外淀粉酶、蛋白酶、纤维素酶的能力,在酶活鉴别培养基上能产生明显的分解圈,48 h透明圈与菌落面积比分别为3.87、4.38、31.42,但未显示产脂肪酶的能力。优化培养基为玉米淀粉10.0 g/L,豆粕粉10.0 g/L,NaCl 5.0 g/L,K2HPO42.0 g/L,CaCO32.0 g/L,优化后培养条件为初始pH 7.0,培养温度30℃,250 mL三角瓶装液体积为25 mL,接种量5.0%,摇床转速200 r/min,根据优化条件,在2 m3罐中扩大培养芽胞数可达到3.8×109cfu/mL,芽胞率达97.4%。

Extracellular enzyme production characteristics and fermentation conditions of Bacillus megaterium JSSWJD were studied. The results showed that it had strong capability to produce extracellular amylase, protease and cetlulase, and could produce obvious enzyme-lytic rings on enzyme activity differential medium, and the ratio of the transparent rings area to the colonies after 48 h was 3.87, 4.38, and 31.42 separately, but showed no ability to produce tipase. The optimum medium formula was： 10.0 g/L corn starch, 10.0 g/L soybean cake powder, 5.0 g/L NaC1, 2.0 g/L K： HPO4,2.0 g/L CaCO3. The optimized culture conditions were： initial pH at 7. 0, 30 ℃, 25 mL of liquid medium filled in 250 mL flask with 5.0% of inoculum, shaker speed at 200 r/min. Under these optimum conditions, the spore concentration reached up to 3.8 × 10^9 cfu/mL by enlarged cultivation in 2 m3 fermentor, and the spore rate reached up to 97.4%.