Enhanced brewery wastewater purification and microalgal production through algal-bacterial synergy

Previous studies on microalgae-based brewery wastewater treatment paid insufficient attention to the relative contributions of microalgae and bacteria on nutrient removal, bacterial community structure and metabolic function, and also the microalgae-bacteria interaction, hindering the large-scale application. This study demonstrated that the bacteria in brewery wastewater promoted the growth of Chlorella sorokiniana to 1.41 g L−1. Collaboration between bacteria and microalgae enhanced the ammonia nitrogen removal up to 96.0% (mainly driven by microalgae) and accelerated dissolved organic carbon degradation (mainly driven by bacteria). Increased humic acid-like substances and reduced soluble microbial by-product-like substances were observed. Functional annotation of prokaryotic taxa (FAPROTAX) analysis demonstrated that bacteria in the brewery wastewater with addition of microalgae (ABS) possessed less abundance of aromatic compound degradation pathway than the treatment without microalgae. Co-occurrence network analysis showed that microalgae induced the dominance of bacteria from module III and exacerbated intraspecies competition within the microbial community in ABS for nutrients. The microalgal biomass in ABS contained high lipid content of 34.9% with good properties for the biodiesel production. Similar results were obtained in 14 L panel photobioreactor with unsterilized brewery wastewater. These results revealed that bacteria and microalgae exerted synergistic effects on the enhanced microalgal growth and brewery wastewater treatment, serving to the promotion of microalgae-based brewery wastewater treatment in a large scale.