解淀粉芽孢杆菌dhs-28的筛选分离及絮凝活性

Flocculating Activity of Marine Bacillus Amyloliquefaciens dhs-28

从渤海湾海水样品中分离筛选出1株絮凝活性最高达83.6%的细菌,经16S rDNA与Biolog鉴定,确定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens),命名为解淀粉芽孢杆菌dhs-28(Bacillus amyloliquefaciens dhs-28)。超声破碎试验证实其絮凝活性仅存在于发酵上清液中。该菌株在LB液体培养基中,37℃,180 r/min,发酵72 h,絮凝活性最高。经硫酸铵沉淀后用3 KD透析袋脱盐,获得该菌株絮凝活性产物。以絮凝活性产物为研究对象,发现其絮凝活性易受酸碱性影响,只在pH值为6～11范围内稳定;但在广范围温度(0～100℃)内保持稳定。糖类、蛋白质、脂类与核酸定性反应初步鉴定其絮凝活性产物主要为蛋白质,同时还含有少量糖类。紫外扫描揭示其成分较复杂。

A bacterial strain whose flocculating rate could reach 83.6% was isolated from Bohai seawater samples.The strain was identified as Bacillus amyloliquefaciens by 16S rDNA definition and Biolog test and was nominated as Bacillus amyloliquefaciens dhs-28 ultimately.Ultrasonication test confirmed that its flocculating activity was in fermentation supernatant.Incubating in LB liquid culture at 37 ℃,180 r /min for 72 h,the strain had the highest flocculating activity.Flocculating active substances were obtained by ammonium sulfate precipitation and dialysis and its flocculating activity was sensitive to pH.It could only maintain flocculating activity while pH varied from 6 to 11,but in a wide temperature range from 0 ℃ to 100 ℃.Saccharide,protein,lipid,nucleic acids qualitative tests showed the flocculating active substances were mainly composed of proteins,as well as a few saccharides.UV scan results suggested the composition of its flocculating active substances was complicated.