Project description:It is a cost-effective production method to synthesize polyhydroxyalkanoate (PHA) through mixed bacterial consortium fermentation. Pseudomonas balearica R90 and Brevundimonas diminuta R79, which represent the species of abundance increase in the propylene oxide activated sludge, were selected as the model to study the interaction mechanism of PHA synthesis by co-culture between strains. RNA-Seq analysis showed that the expression of acs and phaA genes of R79 and R90 increased in the mixed culture group, which enhanced their ability of acetic acid utilization and poly-β-hydroxybutyrate (PHB) synthesis. So the dry cell weight and the yield of PHB in the mixed culture group was prominently higher than that in the pure culture group. In addition, two-component system genes, quorum- sensing genes, flagellar synthesis related genes and chemotaxis related genes in R90 were enriched at 4 days, so R90 could adapt to the domestication environment more quickly, making the proportion of R90 higher than that of R79 at 4 days. However, the acs gene expression of R79 was higher than that of R90. Therefore, R79 can make better utilize acetate in the domestication solution environment, thus occupying the final dominant position.
