产抑菌物质SDLH菌株的鉴定及发酵产物稳定性研究

目的：对1株产抑菌物质的中华稻蝗内生菌SDLH进行鉴定,并对其发酵产物稳定性进行研究。方法：通过观察生长情况及菌落特征形态学、氨基酸利用、糖发酵、脱羧酶反应生理等生化检测以及16S rDNA序列测定对菌株SDLH进行分类鉴定,并在不同条件（温度、pH、光照等）下测定其发酵产物的抑菌稳定性。结果：菌株SDLH符合肠杆菌科细菌的一般特征;生理生化特征均与Serratia marcescens的特征基本一致;菌株SDLH的16S rDNA序列长度为1 457bp。Gene bank序列登录号为EU525929。其序列在1 457bp范围内与已知的模式菌株粘质沙雷氏菌（AB244291.1）16S rDNA序列部分有100%的相似性。其发酵产物在温度（40℃~60℃）下抑菌活性稳定,在高温（≥80℃）下失去活性;在酸性条件（3≤pH〈7）下,抑菌活性无明显变化,在碱性条件（pH≥10）下,抑菌活性下降;光照2~6h后抑菌活性下降。结论：菌株SDLH属于沙雷氏菌属（Serratia）粘质沙雷氏菌（Serratia marces-cens）,其发酵产物具有较强稳定性,可置避光、pH中性、常温环境中短期保存,经提高活性、纯化等处理后可能作为新型天然防腐剂应用于食品领域。

Identification of One Producing the Antibacterial Substance Microorganism Strain SDLH and the Stability of Its Fermentation Products

Objective:Identification for the endophyte of the Oxya chinensis,the SDLH,which can produce the antibacterial substance,and analysis for the stability of the ferment substance.Method: Through the observation of the growth and morphologic characteristic of the colony,usage of the amino acid,ferment of the glucide,decarboxylase reaction and determination of the sequence of the 16S rDNA in order to identify and classify the SDLH.The anti-fungal stability under different conditions(temperature,pH,illumination) were determined.Result: The SDLH has the general character of the Enterobacteriaceae,the physiological-biochemical characteristics are identical with Serratia marcescens.The length of the 16S rDNA is 1457bp,accession number of the Genbank is EU525939.The 1457 bp of the sequence has 100% similarity with the 16S rDNA of the Serratia marcescens(AB244291.1).The ferment substance has stable anti-bacterial stabilities under temperature(40℃～60℃),and lost the activity under high temperature(≥80℃);has no obvious activity change under the acid environment(3≤pH<7),and decreased under alkalescence environment(pH≥10);decreased after illumination for 2～6 hours.Conclusion: The SDLH belongs to the Serratia marcescens of Serratia,the ferment substance has strong stability,and can be conserved under the environment of lucifuge,neutral pH and moderate room temperature.It can be used as a new kind of natural antiseptic for the food industry after the treatment of increase the activity and purification.