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Effect of Pseudoanabaena sp. on emission of 2-MIB in drinking water reservoir Huang, Xin; Huang, Zhifeng; Chen, Xueping School of Environment and Chemical Engineering, Shanghai University, Shanghai 200444, China; Huang, Xin(1980- ), male, associate professor, Shanghai university. Tel: 021-66137748; E-mail: [email protected] Supported by the National Science Foundation Project of China (No. 51678351) Abstract: With the increasingly serious water eutrophication, off-flavor problem caused by cyanobacteria has been frequently reported. These problems have caused concerns and complaints about water quality, and become a key research direction. 2-methylisoborneol (MIB) is one of the most commonly detected off-flavor chemicals present in drinking water. However, it is difficult to real-time monitoring 2-MIB because of the exceptionally low detection threshold, result in 2-MIB can’t prevention timely. Quantitative real-time PCR (qPCR) is useful for quantifying responsible for 2-MIB-producers by quantifying 2-MIB synthase gene. It has been reported that genes were closely associated with 2-MIB synthesis by culturing cyanobacteria in laboratory, but the monitoring of 2-MIB-producer in drinking water reservoir has not been reported. To find the responsible for 2-MIB producers, in this study, both water samples and sediment samples were taken from the surface layer at five locations in a drinking water reservoir from October 2015 to September 2016. The biomass and taxonomic units of algal communities in water samples were determined via blood counting chamber and microscopic counting. 2-MIB concentrations were determined by SPME-GC-MS, and the synthesis gene of which in water and sediment samples were quantified by qpcr. The Shannon–Weaver indices (H’) were used to evaluate bacterial diversity. Seasonal variations of algal groups analyzed by principal components analysis(PCA), and the effects of environmental factors on bacterial community were analyzed by canonical correspondence analysis (CCA). The results showed that the community of algal groups at different season were obviously variations, and Pseudoanabaena sp. of Cyanobacteria was the dominant algal group in summer, the biomass of which was ranged between 31.52% - 60.11%. The species diversity indexes in summer and winter (<2) were lower than that in spring and autumn (>2). Copy number of 2-MIB synthesis gene and the cell number of Pseudoanabaena sp. had similar variation tendency, both of them increased in August rapidly. There are obviously positive correlation between copy number and cell number (R2=0.401), 2-MIB concentration (R2=0.536). Moreover, gene copy number in water samples was strong correlated with that in sediment samples (R2 = 0.842). In addition, the CCA results suggested that TP, Chl a, phycocyanobilin and gene copy number in sediment (p<0.05) were significantly affect the bacterial community composition. These results suggested that Pseudoanabaena sp. was dominant species in the water reservoir, and which may play key role in the producer of 2-MIB. The algae community in the water reservoir were significantly impacted by TP, Chl a, phycocyanobilin. This study may provide appropriate management and treatment options to water utilities. In addition, because of the high correlation coefficient between gene in water and sediment, 2-MIB might release from sediment to water bodies, it needs further research to strengthen the monitoring of sediment.