Enrichment and acclimation of an anaerobic mesophilic microorganism?s inoculum for standardization of BMP assays.

Appropriate enrichment of anaerobic microorganism?s consortium is crucial for accurate biochemical methane potential (BMP) assays. An alternative method to produce and maintain a mesophilic methanogenic inoculum was demonstrated. Three sources of inoculum were mixed and acclimated for 857 days in order to reach steady conditions (pH = 7.90 ± 0.46; VS/TS > 50%; VFA/alkalinity = 0.16 ± 0.04 gAcetic Acid/gCaCO3 ). Biogas yield >80% was obtained after 70 days of inoculum acclimation in comparison to standard cellulose (>600 mLN/gVS). Methanogen community analysis based on 16S rDNA of the inoculum revealed Archaea concentration of 3 1012 gene copies/g (Methanobacteriales 8 1010; Methanomicrobiales 8 1010; and Methanosarcinales 4 1011 gene copies/g). The proposed method for development and maintenance of microorganism enrichment inoculum demonstrates consistent BMP data which is a requirement for dependable prediction of biogas production at field scale operations.