芽孢杆菌B13的分离鉴定及其抑菌作用研究

试验旨在发掘有效的抗性菌以替代部分抗生素,并研究其抑菌作用,以大肠杆菌K88、鼠伤寒沙门氏菌和金黄色葡萄球菌为指示菌,采用凝胶打孔法从猪肠道内容物中筛选出一株对3种病原菌均具有抑菌活性的菌株,利用形态特征观察、革兰氏染色、16SrDNA序列同源性比对鉴定菌株,并对其抑菌条件和生长条件进行优化。结果显示,试验筛选到1株对大肠杆菌K88、鼠伤寒沙门氏菌和金黄色葡萄球菌均具有较强抑制作用的菌株,经鉴定确定其为芽孢杆菌(Bacillus sp.),并命名为芽孢杆菌B13。此分离菌为革兰氏阳性菌,单生或成对生长。生长试验结果表明,该分离菌在pH为6.0,温度为34℃,以蔗糖为碳源、蛋白胨为氮源时,生长速度最快;在pH为7.0,温度为35℃,以麦芽糖为碳源、蛋白胨为氮源时,抗鼠伤寒沙门氏菌、黄色葡萄球菌和大肠杆菌K88活性最高。本试验通过对芽孢杆菌B13的特性进行研究发现,此菌株具有较好的抑菌效果,在抑菌方面具有良好的开发应用前景。

Isolatiog,Identification and Study of a Bacillus sp.B13 with High Antibiotic Character

The aim of the experiment was to find a new antimicrobial bacterium,then analyze its main metabolic antimicrobial characterization.A strain was isolated from pig intestinal contents with resistance to E.coli K88,Staphylococcus aureus and Salmonella Typhimurium by gel punching.Its taxonomic status determined by colonial morphology,Gram staining and 16S rDNA sequence analysis.Then the fermentation medium and conditions for its growth and antimicrobial activity were optimized.The results showed that the isolated strain was identified as Bacillus sp.and showed an excellent antimicrobial activity against E.coli K88,Staphylococcus aureus and Salmonella Typhimurium,and then was named as Bacillus sp.B13.It was Gram-positive,single-birth or in pairs of growth.Auxanographic analysis showed that the optimal growth condition of Bacillus sp.B13 was that the pH was 6.0,temperature was 34℃,sucrose as carbon source and peptone as nitrogen source.Results of antimicrobial activity against E.coli K88,Staphylococcus aureus and Salmonella Typhimurium showed the optimal condition was that pH was 7.0,temperature was 35℃,maltose as carbon source and peptone as nitrogen source.In conclusion,Bacillus sp.B13 had good bacteriostatic activities and had great development potential applied prospects in the production.