Study of the Microbial Composition and Comparative Biogas Production from Fresh, Dried and Cow-Dung Seeded Pumpkin (Cucurbita maxima) Residue

Abstract

The research study was aimed at identifying the microorganism(s) associated with biogas production as well as comparing the biogas production potential of the fresh, dried and cow dung seeded pumpkin wastes as substrate. The samples were procured from different fruit seller locations within Sokoto metropolis and the study conducted within a period of five weeks (35 days). Standard microbiological methods were used for isolating and identifying the microbes while fabricated anaerobic bio-digesters were used to ascertain the biogas production from the substrates. Analysis revealed that the pH varied between 6.30 to 7.20 and 5.0 to 6.2 before and during/after the anaerobic digestion respectively. Anaerobic bacteria isolated were identified as Enterobacter spp and Escherichia coli. The results showed 4850, 1430 and 1770 cm3 biogas production from the fresh, dried and cow dung co-seeded substrates respectively during the retention periods with a calorific value of 4773 kcal/kg. The volume of biogas produced varied significantly (p<0.05) between the substrate treatments and the digestion intervals (days). GC-MS analysis confirmed the identity of the produced methane. This study confirmed the role of bacteria as well as the capability of the substrate to produce biogas production in an in vitro bio-digester system.