Research On Differentially Expressed Proteins Of Bioflocculant Producing Bacteria And Analysis Of Their Functions

As an efficient, nontoxic, non-secondary contaminative, biodegradable and environmental-friendly green wastewater disposal agent, bioflocculant is one of the most potential flocculants and has been widely used in treating various industrial and domestic sewages. The compound bioflocculant (CBF) was produced by our lab, which was a novel bioflocculant produced by two bioflocculant producing bacteria of F2 and F6 through two-step fermentation. The effective component of bioflocculant produced by F2 and F+ (mixed cultivation from F2 and F6) was determined as extracellular polysaccharide. In the paper, differentially expressed proteins related to flocculating metabolic pathway of bioflocculant producing bacteria and regulation of their functions were researched by proteomics methods, the flocculating mechanisms were revealed in molecular level, regulating strategies of producing bioflocculant in industry were proposed.First, the difference of production and component of bioflocculant between in bioflocculant media and in minimal media were researched. F2 and F6 expressed differentially expressed proteins in bioflocculant media compared with minimal media. These differentially expressed proteins were the direct reason to induce and produce large amount of main and effective polysaccharide of bioflocculant in bioflocculant media.Then, differentially expressed proteins of F2 and F6 in bioflocculant media compared with minimal media were separated, identified and analyzed in function by proteomics technologies——SDS-PAGE, two-dimensional electrophoresis (2-DE) and mass spectrum (MS). The changes of total proteins of F2 and F6 grown in bioflocculant media compared with minimal media were researched by SDS-PAGE. 58 of differentially expressed proteins of F2 and 14 of differentially expressed proteins of F6, which were related to flocculating metabolic pathway, were identified. The changes of cytosol proteins of F2 grown in bioflocculant media compared with minimal media were researched by 2-DE. 28 of differentially expressed proteins related to flocculating metabolic pathway of F2 were identified. By analyzing functions of differentially expressed proteins related to flocculating metabolic pathway of bioflocculant producing bacteria, the flocculating mechanisms of bioflocculant producing bacteria were revealed in proteomics level.Finally, through a number of shake flask tests, the related regulation laws in production of bioflocculant were researched and the relationship between fermentation conditions, functions of differentially expressed proteins and changes in producing bioflocculant were established. Three dimentional regulating strategies, such as substrate, fermentation parameters and rejuvenation of bioflocculant producing bacteria, were brought up to regulate bioflocculant producing bacteria to produce bioflocculant by compound substrate in industry.In the paper, the flocculating mechanisms of bioflocculant producing bacteria were researched in proteomics level, which can establish solid theory foundations to fully analyze and regulate flocculating metabolic pathway of bioflocculant producing bacteria. Based on analyzing functions of differentially expressed proteins related to flocculating metabolic pathway, regulating strategies were brought up, which can play important directing roles to raise the output of bioflocculant, to regulate bioflocculant producing bacteria to produce bioflocculant in industry.