Biosurfactants Enhanced Methane Production from Organic Solid Waste using Co-culture of Methanosarcina mazei and Pseudomonas aeruginosa

Abstract

The effect of biosurfactants (surfactin and rhamnolipid) on the methane production from organic solid waste (OSW) investigated using co-culture of facultative anaerobes Methanosarcina mazei and Pseudomonas aeruginosa+Bacillus subtilus. The biosurfactants were applied in the concentration ranges 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 5.g/l respectively. Cumulative methane production (P), maximum methane production rate (Rmax) and lag phases (e) were analyzed using the modified Gompertz model. Results revealed that both the biosurfactants were effective in methane production enhancement. The maximum cumulative methane production of 2.10 L-CH4/L-substrate and 1.91 L-CH4/L-substrate recorded at 3.5% surfactin and 3.0% rhamnolipid, respectively. Corresponding highest methane yields were 77.7 mL CH4/g Carboinitial and 70.7 mL CH4/g Carboinitial, respectively. The lag phase decreased from 13.9±0.2 hours at control to a minimum of 9.93±0.04 and 10.02±0.02 surfactin and 3.0% rhamnolipid, respectively. Volatile fatty acid generation subsequently increased with biosurfactants additive.