管材对供水管网生物膜微生物种群多样性的影响

研究了3种管材(灰口铸铁管、镀锌管和不锈钢复合管)对管网生物膜微生物种群多样性的影响.采用R2A平板培养计数可培养细菌、荧光定量PCR计数细菌总数、流式细胞法确定活菌比例、扫描电镜观察生物膜形态,高通量测序研究管段生物膜微生物种群多样性.研究结果表明:灰口铸铁管可培养菌数和细菌总数都最高,其次是镀锌管,不锈钢复合管可培养菌数和细菌总数都最少,但活菌比例方面镀锌管活菌比例高于灰口铸铁管和不锈钢复合管.扫描电镜结果与可培养菌数及细菌总数结果一致,即灰口铸铁管细菌量最高,不同管材管壁生物膜细菌形态皆以球菌和杆菌为主,并无显著差异.微生物种群多样性结果显示:灰口铸铁管生物膜种群多样性最高,镀锌管生物膜种群多样性相对较为单一,不锈钢复合管生物膜种群多样性最低.饮用水管网生物膜种群以变形菌门为主,各管道变形菌门都高达90%以上,不同管材生物膜细菌群落组成有很大差异.本研究结果对今后饮用水供水管段材料的选取具有指导性意义.

Impact of pipe materials on bacterial population diversity in drinking water biofilm

The influence of different material pipes on the microbial diversity were studied in this paper. Heterotrophic plate counts (HPC) with R2 agar and qPCR were used to count the number of culturable bacteria and total bacteria, respectively. The proportion of live bacteria was measured with flow cytometry and biofilm's morphology was observed with scanning electron microscopy (SEM). High-throughput sequencing was also used to study the microbial diversity of biofilm. The results showed that the number of culturable bacteria and total bacteria of grey cast iron pipe was the highest among the three pipes, while the stainless steel pipe had the least number of culturable bacteria and total bacteria. The observation of SEM provided similar results, and the main bacteria were coccus and bacillus. However, the proportion of living bacteria in galvanized pipe was higher than grey cast iron and stainless steel pipe. The highest species richness and diversity were found in the samples from grey cast iron pipe, and the lowest was in the samples from stainless steel pipe. Overall, more than 90% of the diversity in all samples was associated with the phyla Proteobacteria, and the bacterial community composition of biofilm from the pipes was significantly different.