Performance of different bacteria-microalgae-fungi consortium cultivation in nutrient removal and biogas upgrading by induction of GR24 and 5-Deoxystrigol

Abstract

This study evaluated the effects of 5-Deoxystrigol (5 DS) concentration on the growth characteristics, the photosynthetic performance of different bacterial-microalgae-fungal symbiotic systems, and the simultaneous treatment of biogas slurry and biogas. Suitable 5 DS concentrations enhanced the metabolism and photosynthesis of microalgae in the symbiotic system, leading to the rapid growth and good purification performance of the symbionts. The growth and purification performance of symbiotic systems were affected more by fungal than algae species. Specifically, Ganoderma lucidum (G. lucidum) performed better than Pleurotus ostreatus (P. ostreatus), while Chlorella vulgaris (C. vulgaris) performed better than Scenedesmus obliquus (S. obliquus). The Bacillus licheniformis (B. licheniformis)-C. vulgaris-G. lucidum symbiote exhibited the best purification effectiveness for biogas slurry and biogas, with a removal efficiency of chemical oxygen demand, total nitrogen, total phosphorus, and CO2 of 84.71 ± 8.23%, 83.94 ± 8.21%, 86.48 ± 8.36%, and 68.74 ± 6.36%, respectively, under the recommended 10−11 M 5 DS. Moreover, the purification effectiveness was positively correlated with the growth characteristics and photosynthesis performance of the bacterial-microalgae-fungal co-culture system. The findings of this study will facilitate the wide application and development of symbiotic systems in biogas slurry treatment and biogas upgrading.