高产胞外多糖干酪乳杆菌的太空诱变选育

Mutation of Lactobacillus casei with high production of exopolysaccharides by space mutagenesis

为了提高干酪乳杆菌G5的胞外多糖产生能力,采用太空诱变技术对其进行选育,从中筛选出高产胞外多糖菌株。通过富集培养、平板筛选、脱脂乳发酵和遗传稳定性实验,最终得到两株高产胞外多糖且遗传稳定性较好的突变株EPS-33和EPS-43。突变株EPS-33和EPS-43在25℃发酵脱脂乳,发酵结束时胞外多糖的产量分别220.42和198.49mg/L,为出发菌株的1.9倍和1.7倍。2个突变菌株与出发菌株产胞外多糖的变化趋势基本相同,但产量大幅增加。

A starting strain of Lactobacillus case/G5 was mutated by space mutagenesis technology to screen strains with high production of exopolysaccharides. Through enrichment culture,plate screening,skim milk fermentation and genetic stability experiment,we finally got two stable mutant strains EPS-33 and EPS-43 with high production of exopolysaccharides.while mutant strains EPS-33 and EPS-43 fermented in skim milk at 25℃,the yield of exopolysaccharides were 220.42mg/L and 198.49mg/L,which were 1.9 and 1.7 times of starting strain. Exopolysaccharides production of the two mutant strains had the same change trend as starting strain, but the two mutant strains had a sianificant increase, in ~ production.