Observation of few GR24 induced fungal-microalgal pellets performance for higher pollutants removal and biogas quality improvement

Abstract

Microalgae-based technology has attracted increasing attention in the purification of digestate and biogas, owing to environmental friendliness and economic viability. However, mono-microalgae cultivation cannot efficiently remove pollutants and CO2. In this study, an effective approach was used to simultaneously purify digestate and biogas, focusing on the construction of fungal–microalgal associations, optimization of concentration of strigolactone analogue (GR24), evaluation of the growth and photosynthetic performance of symbionts and purification of digestate and biogas. GR24 concentration of 10−9 M and shaking speed of 160 rpm were found to be favorable for the formation of fungal–microalgal pellets. The highest efficiencies with which chemical oxygen demand, total nitrogen, total phosphorus, and CO2 were eliminated were obtained in the cultivation system of fungus Pleurotus geesteranus and microalgae Chlorella vulgaris, resulting in removal rates of 86.17% ± 7.92%, 87.47% ± 8.14%, 85.21% ± 7.69%, and 72.41% ± 6.37%, respectively. Moreover, Pleurotus geesteranus promoted a significant increase in the biomass of Chlorella vulgaris, and the growth performance and photosynthesis of pellets were found to be consistent with the results of pollutant and CO2 removal efficiencies. Collectively, the findings provide new insights into the simultaneous purification of digestate and biogas by cultivating fungal–microalgal pellets.