饲用芽孢杆菌的筛选鉴定及固态发酵培养基的优化

为了筛选鉴定供试菌株,对其固态发酵培养基组分进行优化。从8株供试菌株中筛选出两株优良菌株B02和B06,采用形态特征和生理生化鉴定方法、16SrDNA序列测定和系统发育分析对B02和B06进行鉴定;以活菌含量为指标,通过L9(34)正交试验,对固态发酵培养基组分的不同配比进行优化。结果表明,B02为蜡样芽孢杆菌(Bacillus cereus),B06为枯草芽孢杆菌(Bacillus subtilis)。B02和B06最佳培养基配比分别为麦麸695.6g/kg、豆粕87.0g/kg、玉米粉87.0g/kg、米糠130.4g/kg和麦麸761.9g/kg、豆粕95.2g/kg、玉米粉95.2g/kg、米糠47.7g/kg。B02和B06在麦麸、豆粕等发酵物料中生长良好,在优化后的培养基中培养最高活菌含量分别可以达到1013 cfu/g和1010 cfu/g以上,具有很大的开发利用潜力。

Screening and Identification of Forage Bacillus and Optimization of Its Solid state Fermentation Medium

This research screened and identified the Bacillus keeping in the laboratory, also optimized its culture medium of solid state fermentation. B02 and B06 strains were screened from eight tested bacilli by the physiology and homological analysis of 16S rDNA sequence and optimized the ratios of different components in the culture medium of solid fermentation through L₉(3⁴) orthogonal test, taking the quantities of Bacillus as an index. The results showed that B02 was identified as B.cereus strain,B06 as B.subtilis strain. The best components ratio for fermentation was: wheat bran 695.6 g/kg, soybean meal 87.0 g/kg, corn flour 87.0 g/kg, and rice bran 130.4 g/kg for B02 and wheat bran 761.9 g/kg, soybean meal 95.2 g/kg, corn flour 95.2 g/kg, and rice bran 47.7 g/kg for B06.B02 and B06 grew well in fermented medium including wheat bran and soybean meal. The optimized culture medium of solid state fermentation had a high development potential, since the quantities of bacillus could reach up to 10¹³ cfu/g and 10¹⁰ cfu/g, respectively.