Microalgal Addition to Activated Sludge Changed Bacterial Community and Enhanced Production of High Value Fatty Acids

Abstract

The main objective of this study was to evaluate the impact of microalgae addition on bacterial and fungal communities and pollutant removal. Bacterial and fungal communities, pathogenic microorganism abundance, pollutant removal efficiency, and high value fatty acid production were investigated in a microalgae-activated sludge (MAS) system, with microalgae (M) or activated sludge (AS) system as controls. The results showed that removal efficiencies of nitrogen and phosphorus by MAS reached 71% and 97%, respectively, which were higher than those by AS. The abundances of pathogenic microorganisms and anaerobic fungi decreased substantially compared to those in the AS system. The MAS system enhanced microalgal oleic acid (OA) production twice as M system. Additionally, it was found that the pH variation of MAS was very different with AS and MAS system, indicating that the exchange of O2 and CO2 between microalgae and bacteria occurred in microalgae-bacterial consortia from another perspective.

Keywords: Microalgae, activated sludge, Bacterial community, High value fatty acids