微生物絮凝剂的菌种分离筛选及其产生条件的选择  

Isolation and Screening of Microbial Flocculant-producing Strains and the Selection of Growth and Flocculant-producing Conditions

作　　者：韩宇[1] 马光庭[1] 

机构地区：[1]广西大学生命科学与技术学院,南宁530004

出　　处：《基因组学与应用生物学》2009年第6期1063-1070,共8页Genomics and Applied Biology

基　　金：国家自然科学基金项目(30460114)资助

摘　　要：本研究采用根瘤菌选择性培养基和稀释平板法,从广西大学校园罗汉松和相思树植物根瘤中总共分离出20株菌落光滑型菌株,并分别对其发酵物作絮凝试验。研究结果表明,从罗汉松根瘤中筛选出一株絮凝率较高的菌株,暂编号为P2。对P2进行形态学观察结果表明:其菌落圆形、凸起、光滑、无色透明,其细胞杆状、菌体大小为0.5×(1～2)μm,该类细菌为革兰氏阴性细菌、有糖被、无芽孢,周生鞭毛;测序分析表明其16S rDNA序列与Rhizobium sp. DV816S rDNA(DQ873665.1)同源性达98%以上;生长和产絮凝剂最佳条件如下:配方为甘露醇10%,K2HPO4 0.3%,酵母膏0.03%,NaCl 0.5%,(NH4)2SO4 0.01%,脲0.03%液体培养基中,30℃,起始pH为7.0,转速为200r/min条件下培养发酵72h,产生的絮凝剂可使浓度为5000mg/L高岭土悬浮液在20min内絮凝率最高为92%。In this paper,we isolated twenty smooth-clony strains from nodules of yaccatree(Podocarpus macrophyllus) and Taiwan acacia(Acacia confuse) in Guangxi university by employing selective medium for nodule-bacteria and dilution-plate approach,and further made experimental study on flocculation of their fermentations,respectively.A strain,designated as P2 with higher flocculanting rate,was selected from Podocarpus macrophyllus.Morphological observation showed that the colony presented round-shape,raised,smooth,colorless,transparent,the cell was rod-shaped,and size of the rod is 0.5 μm in length and ranged from 1 to 2 μm in width.It was decribed as gram-negative bacterium with capsule,and peritrichous flagella,while without endospore.Sequence analysis demonstrated that the 16S rDNA sequence of P2 had more than 98% homology with that in Rhizobium sp.DV8(DQ873665.1).In this research,we established the optimum conditions for the growth and flocculant production which containing 30℃,initial pH 7.0,rotating speed 200 r/min,cultured for 72 h on the medium supplemented with 10% mannite,0.3% K2HPO4,0.03% yeast extraction,0.5% NaCl,0.03% urea,the products under which showed flocculanting rate of 92% against 5 000 mg/L kaolin clay suspension within twenty minutes.

关 键 词：微生物絮凝剂 菌种筛选 条件选择 

分 类 号：X703.5[环境科学与工程—环境工程]