脉冲强光诱变保加利亚乳杆菌高产胞外多糖

Enhancement of exopolysaccharides production in L.bulgaricus by intense pulse light mutagenesis

为了研究脉冲光技术应用于微生物诱变育种的可行性以及获得多糖高产突变株,以产糖菌保加利亚乳杆菌L.bulgaricus IMAU40160为出发菌株,进行脉冲强光诱变处理。通过红外光谱、扫描电镜以及超氧阴离子(O_2^-)和羟基自由基(·OH)清除能力的测定,对比分析诱变前后菌株多糖的简单结构和抗氧化能力。SDS-PAGE电泳对脉冲强光的诱变机理进行初探。结果表明,利用脉冲强光诱变技术可选育得到多糖高产突变株L27,其多糖产量高达(490.98±12.26)mg/L,较原始菌株提高了98%。结果表明,脉冲强光诱变不会对菌株多糖官能团产生影响;诱变处理后菌株多糖表面呈现不规则多孔状;脉冲光处理提高了菌株多糖的抗氧化活性,引发了突变株差异蛋白的表达,为脉冲强光应用于优良菌株选育的进一步研究提供了理论依据。综上,脉冲强光技术可应用于L.bulgaricus IMAU40160多糖高产突变株的诱变选育。

In order to explore the feasibility of intense pulse light（IPL）technology used in microbial mutant breeding and obtain mutant strains with high yield of polysaccharides,the wild strain of L.bulgaricus IMAU40160 was mutated by IPL.Fourier transform infrared and scanning electron microscopy were used to analyze the primary structure of polysaccharides.Based on superoxide polysaccharide（O2--）and hydroxyl radical（·OH）scavenging ability,the antioxidant capacity of polysaccharides was studied.The mutagenic mechanism of IPL was explored using SDS-PAGE.Results showed that mutant strain L27 could be obtained by IPL mutant breeding and the yield of polysaccharide was（490.98±12.26）mg/L,which increased by 98%compared with that of the wild strain.IPL treatment would not influence the chemical bonds of polysaccharides.After the mutagenesis,polysaccharides showed irregular porous surface morphology and exhibited stronger antioxidant activities.IPL could cause the change of strain protein expression.This result would provide a theoretical basis for further research on the application of IPL in breeding superior strains.In conclusion,IPL could be applied in mutant breeding of mutants with high yield polysaccharide of L.bulgaricus IMAU40160.