Nutrient Requirement for the Degradation of Cellulose to Methane by a Mixed Population of Anaerobes

Abstract

SUMMARY: A synthetic medium containing inorganic sources of N, P, Fe, S, Ca2+ and Mg2+, trace minerals and essential vitamins was developed for anaerobic degradation of cellulose to CH4. A mixed culture obtained from sewage sludge and grown in batch culture in this medium degraded about 4 g cellulose l-1 week-1 and produced about 710 ml total gas per g cellulose degraded. The gas produced contained between 51 and 56% CH4, the remainder being CO2. For maximum degradation of cellulose to CH4 and CO2, the requirement for essential salts other than HCO3-, Fe and S2- was comparable to that of other anaerobes. NH4+ or Na2CO3 at 20 to 24 mM and total Fe at 0\ub74 to 0\ub76 mM gave optimum conversion of cellulose to CH4, while the inclusion of additional S2- in the presence of 1\ub775 mM-SO42- was not required.Peer reviewed: NoNRC publication: Ye