Lipid accumulation capability of typical non‐acclimated activated sludge microbial consortia using methane gas as secondary carbon source

Abstract

This work experimentally demonstrates that wastewater activated sludge microbial consortia can utilize methane resulting in lipid content enhancement. Activated sludge was cultivated using a synthetic wastewater as culture media. After initial purging with air, analytical grade methane gas was added in the culture headspace. The cultures were cultivated in batch-mode for 120 hours at 25 • C in 500-mL bioreactors with 125-mL working liquid volume. Results indicate that methane gas was utilized by activated sludge microbial consortia under a similar pattern of microbial respiration as the control cultivated only with air. The activated sludge in the methane-purged bioreactors showed lipid enhancement (0.123 ± 0.037 mg lipid per mg biomass) and biomass growth (0.626 ± 0.163 mg biomass per mg glucose plus methane), which were higher than those in the control runs (0.009 ± 0.034 mg lipid per mg biomass and 0.225 ± 0.133 mg biomass per mg glucose).