Performance of a biocrust cyanobacteria-indigenous bacteria (BCIB) co-culture system for nutrient capture and transfer in municipal wastewater.

This study aimed to explore the potential for transferring nutrients from municipal wastewater through the cultivation of biocrust cyanobacteria, since little is known regarding the growth and bioremediation performance of biocrust cyanobacteria in actual wastewater, especially their interaction with indigenous bacteria. Therefore, in this study, the biocrust cyanobacterium, Scytonema hyalinum was cultivated in municipal wastewater under different light intensities, to establish a biocrust cyanobacteria-indigenous bacteria (BCIB) co-culture system, in order to investigate its nutrient removal efficiency. Our results revealed that the cyanobacteria-bacteria consortium could remove up to 91.37 % and 98.86 % of dissolved nitrogen and phosphorus from the wastewater, respectively. The highest biomass accumulation (max. 6.31 mg chlorophyll-a L) and exopolysaccharide secretion (max. 21.90 mg L) were achieved under respective optimized light intensity (60 and 80 μmol m s). High light intensity was found to increase exopolysaccharide secretion, but negatively impacted cyanobacterial growth and nutrient removal. Overall, in the established cultivation system, cyanobacteria accounted for 26-47 % of the total bacterial abundance, while proteobacteria consisted up to 50 % of the mixture. The composition and ratio of cyanobacteria to indigenous bacteria were shown to be altered by adjusting the light intensity of the system. Altogether, our results clearly illustrate the potential of the biocrust cyanobacterium S. hyalinum in establishing a BCIB cultivation system under different light intensity for wastewater treatment and other end-applications (e.g., biomass accumulation and exopolysaccharide secretion). This study presents an innovative strategy for transferring nutrients from wastewater to drylands through cyanobacterial cultivation and subsequent biocrust induction.