乳酶生生产用菌种的全基因组序列分析研究

Whole genome sequence analysis for lactasin production strain

目的了解我国乳酶生的生产用菌种全基因组分子特征。方法将乳酶生的生产用菌种屎肠球菌CMCC32901培养后,依次进行形态观察、生化鉴定与16S rRNA基因序列测定,并应用高通量测序技术,对生产用菌种CMCC32901进行全基因组序列测定,分析基因组基本特征、基因功能、同源性及致病性。结果分析结果显示,发现CMCC32901菌株与NCBI数据库中收录的不同屎肠球菌菌株的16Sr RNA基因序列相似度大于99.5%,与其他肠球菌菌株之间的16S rRNA基因序列相似度均大于92.0%。屎肠球菌CMCC32901染色体全基因组序列全长为2 394 726 bp,平均GC含量为39.1%,共含有2718个基因,其中具有COG功能2059个,参与KEGG代谢通路1402个。同源性分析显示其基因组中编码2589个屎肠球菌特异性蛋白。细菌的致病性预测分析发现在CMCC32901菌株中发现5种对人潜在致病性相关蛋白。结论首次获得了我国乳酶生生产用菌种——屎肠球菌CMCC32901全基因组的基本特征,为后续乳酶生的生产工艺优化和生产用菌种的质量控制奠定了基础。

Objective To understand the molecular characteristics of the whole genome of production strain for lactasin in China.Methods After culturing Enterococcus faecium CMCC32901 for the production of lactasin,the morphological observation,biochemical identification and 16S rRNA gene sequence analysis were performed.The high-throughput sequencing technology was used to determine the whole genome sequence of production strain CMCC32901.The basic characteristics,gene function,homology and pathogenicity of the genome were analyzed.Results The 16S rRNA gene sequence of CMCC32901 had greater than 99.5%similarity with different E.faecium strains included in the NCBI database,and greater than 92.0%similarity for other Enterococcus strains.The whole genome sequence of E.faecium CMCC32901 chromosome was 2394726 bp with an average GC content of 39.1%,and contained a total of 2718 genes including 2059 COG functions and 1402 KEGG metabolic pathways.Homology analysis showed that 2589 predicted coding proteins were specific for E.faecium.Predictive analysis for the bacteria pathogenicity showed that five proteins related to human pathogenicity were found in the genome of CMCC32901 strain.Conclusion It is the first time for obtaining the basic characteristics of the whole genome of the lactasin production strain E.faecium CMCC32901 in China,which lays the foundation for the subsequent optimization of the production process of lactasin production and the quality control of the production strains.