组合介质中太湖土著溶藻菌的优势度分析

Dominance Analysis of Algicidal Bacteria in Artificial Medium from Lake Taihu

[目的]从太湖除藻中试装置中分离筛选具有高效降解微囊藻效果的土著溶藻菌,应用种属特异的16SrDNA对其在组合介质和自然环境中的优势度进行分析。[方法]采集太湖除藻中试装置的组合介质,分离筛选溶藻效果达到40%以上的溶藻菌菌株,应用针对16SrDNA基因的种属特异引物对所筛选溶藻菌进行种属鉴定,采用实时荧光定量PCR技术对相应种属细菌进行优势度分析。[结果]在分离筛选出的20株溶藻菌中有:芽孢杆菌属(Bacillus)7株、假单胞菌属(Pseudomonas)4株、弧菌属(Vibrio)3株,这3类细菌在人工组合介质中的优势度分别占总细菌的比例为4.06%、3.10%、6.27%;占同期自然环境(太湖底泥)样本总细菌的比例分别为0.51%、1.78%、7.55%。其中,芽孢杆菌属在人工介质与太湖底泥中的分布差异有统计学意义(P<0.05)。[结论]太湖除藻中试装置中人工介质上的土著溶藻菌主要为芽孢杆菌属、假单胞菌属和弧菌属,其中芽孢杆菌属在人工介质上的优势度显著高于其在底泥上有优势度。

[ Objective ] To characterize and identify indigenous algicidal bacteria isolated from the artificial medium of algae-removing pilot study in Lake Taihu and to analyze the dominance of bacteria in the artificial medium and lake sediment. [ Methods ] The algicidal bacteria were isolated from the artificial medium and genus-specific PCR based on 16S rDNA gene were applied to identify the dominant bacteria colony. The dominance of bacteria in the artificial medium and lake sediment were determined with a real-time quantitative PCR assay. [ Results ] There were seven strains of Bacillus, four strains of Pseudomonas among the twenty strains of algicidal bacteria isolated. The dominance of Bacillus and Pseudomonas in the artificial medium was 4.06% and 3.10%, respectively, which accounted for 7.16% of the total bacterial population. Additionally, the dominance of genera as above in sediments was 0.51% and 1.78%, respectively. The statistic analysis exhibited that there was significant difference between the dominance of bacteria in artificial medium and that in sediments （ P = 0.028 ）. [ Conclusion ] The main indigenous algicidal types include Bacillus, Pseudomonas and Vibrio in the artificial medium of algae-removing pilot study in Lake Taihu. The dominance of Bacillus in the artificial medium is significant higher than that in sediments, which suggesting that artificial medium has the important enrichment effect on Bacillus and play an important role in the microbial remediation of eutrophic water.