Effects of carbon sources on cell membrane properties and microbial community of activated sludge

Abstract:

[Objective] The purpose of this study was to investigate the effects of carbon sources on cell membrane properties (phospholipid fatty acids composition and fluidity) and microbial community of activated sludge. [Methods] Atomic force microscopy (AFM), phospholipid fatty acids (PLFA) and fluorescence recovery after photobleaching (FRAP), and Miseq analysis technology were used to investigate the effects of the different substrates, glucose, sodium acetate, peptone, glucose?peptone (1?1), sodium acetate?peptone (1?1), on the differences of microbial surface adhesion force, PLFA composition and fluidity, and microbial community in five Sequencing Batch Reactors (SBRs). [Results] The involvement of peptone led to an increase of cell membrane phospholipid fluidity, PLFA composition present a consistency with the content of 18?1ω9c, 15?0iso and 17?0iso increased 53.1%?354.7%, 135.6%?407.9% and 88.1%?264.3%, respectively. The dominant phylum response to carbon sources present inconsistent rules: with glucose and sodium acetate as solo substrate, the dominant phylum were Actinobacteria and Proteobacteria, and the dominant genus were Nakamurella and Flavobacterium, diversity index were 3.65 and 4.25, respectively. At the appearance of peptone, the content of Candidatus Saccharibacteria increased obviously, and the diversity index was in the range of 4.96?5.09. [Conclusion] Principal component analysis (PCA) indicated that the involvement of peptone led to similar PLFA composition. Redundancy analysis (RDA) suggested that carbon sources changed the microbial community, which further influenced the composition of PLFA.