Induction of vitamin B12 to purify biogas slurry and upgrade biogas using co-culture of microalgae and fungi.

Abstract

Different gradient concentrations of vitamin B12 (0, 10, 100, 1,000ngL-1 ) were used in the symbiosis system (Chlorella vulgaris-Ganoderma lucidum or Chlorella vulgaris-Pleurotus ostreatus) to assess their effect on simultaneous purification of biogas and removal of nutrients in biogas slurry using co-culture of microalgae and fungi. When B12 was added to the symbiosis system, biomass growth, intracellular carbonic anhydrase activity (CA), chlorophyll a content (CHL-a), photosynthetic characteristics of the two cultivation system, and removal efficiency of nutrients in biogas slurry and CO2 in biogas were significantly higher than those in the control group. The optimal concentration of B12 was determined to be 100ngL-1 considering the removal efficiency of nutrients and CO2 . Maximum mean chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and CO2 removal efficiencies were 75.98±6.26%, 78.46±6.21%, 80.21±6.83% and 61.08±5.21% in Chlorella vulgaris-Ganoderma lucidum, respectively. This study showed the potential of microalgae and fungi symbiosis system with B12 addition for nutrient removal and biogas upgrading. PRACTITIONER POINTS: Vitamin B12 had positive effects on algal-fungal pellets growth. The optimal vitamin B12 concentration was 100ngL-1 . The highest CO2 remove rate was 61.08% by G.lucidum/C.vulgaris pellets. Vitamin B12 significantly improved photosynthetic performance of pellets.