Bacterial community analysis in mixed culture of Chlorella pyrenoidosa and enriched nitrobacteria

Ammonium sulfate wastewater can cause eutrophication and black odor of water body. Although ammonia nitrogen can be used as nutrient of microalgae, high ammonia nitrogen levels could inhibit the growth of microalgae. Nitrobacteria can transform ammonia nitrogen into nitrate nitrogen. Mono Chlorella pyrenoidosa culture, synchronous mixed culture (mixed-a), and asynchronous mixed culture (mixed-b) systems were examined for their ability to treat ammonium sulfate wastewater. Higher total suspended solid concentration, crude protein yield and heating value yield were obtained in mixed-b, meanwhile with excellent settlement performance. Mechanism analysis of settlement showed that the relative abundance of floc-forming related bacteria Sphingopyxis and Acidovorax were increased generally, while nitrification-denitrifying members were decreased in mixed-b along with the culture proceeding.