[Effects of Bacteria on the Growth of and Lipid Accumulation in Cultivated in Municipal Wastewater].

Cultivating microalgae using municipal wastewater can treat wastewater and recover algal biofuel as an energy source. Wastewater provides necessary nutrients such as nitrogen, phosphorus, and water for microalgal growth. Due to the complexity of the components of municipal wastewater and the complex symbiotic and antagonistic relationship between microalgae and bacteria, it is necessary to select the suitable dominant bacterial species that can promote the microalgae to achieve high lipid production and algal biofuel production using municipal wastewater. Based on the microalgal growth and lipid production, we selected bacteria and W4 bacteria from 13 different types of bacteria and analyzed the microbial community structure of the municipal wastewater at the end of the microalgal culture cycle. Laboratory test results showed that the amount of lipid production by bacteria and W4 was 0.114 g·L and 0.113 g·L, which is 22.58% and 21.50% higher than the production by the control group, respectively. According to the gas chromatography (GC) analysis of the lipids, bacteria and W4 bacteria exerted a relatively low influence on the composition of fatty acids of but increased the content of monounsaturated fatty acids that improve the grade of biodiesel. The results of the analysis of microbial community structure of the municipal wastewater showed that and W4 bacteria reduced the richness and diversity of bacterial communities and have the potential to become the dominant bacterial community.