Microorganisms Associated with Biogas Production Using Vegetable (Telfairia occidentalis) Wastes, Banana Peel and Pig Dung as Substrates

Abstract

The research study was aimed at investigating microorganisms associated with biogas production using vegetable (Telfairia occidentalis) wastes, banana peel, and pig-dung as substrates. Marian market, Watt market and University of Calabar pig farm were randomly sampled within Calabar metropolis for collection of samples. The study was completed within a period of six month. Standard microbiological methods and anaerobic biodigesters were used to screen the isolates and the wastes substrate for biogas production. Analysis revealed that the temperature of raw substrates ranged between 21°C and 39°C while the pH varied between 6.10 and 7.21 during digestion. Highest mean bacterial counts was 8.87±3x106 cfu/g and fungal count of 5.67±105 cfu/g were obtained in the combined substrates of banana peel, vegetable waste and pig dung (BP + VW + PD) before digestion, as compared to mean bacterial counts of 8.62±1.4x106 fu/g and fungal counts of 5.55±1.7x105 cf/g obtained during digestion. Anaerobic bacteria isolated were identified as, Pseudomonas sp, Escherichia coli, Bacillus sp, Salmonella sp, Staphylococcus aureus, Serratia sp, Shigella sp, Micrococcus sp, Proteus vulgans, Citrobacter sp and Klebsiella sp, while fungi isolated were identified as Fusarium sp, Mucor sp and Penicillium sp. Methanogenic bacteria isolated were identified as Methanothrix sochngenii, Methanococcoides methylutens and Methanoculles bourgense. The volume of biogas produced and the percentage methane yield varied signficantly (p<0.05) between the substrate treatments and the digestion internals (days). However, the study has shown that the role of methanogens and other complementing bacteria and fungi in biogas production is indispensable.