CHARACTERIZATION OF BACTERIA ASSOCIATED WITH BIOGAS PRODUCTION USING COW DUNG AND RICE HUSKS.

Abstract

This study explored the production of biogas, a renewable energy source, through anaerobic digestion of rice husk (RH) and cow dung (CD). The research used 10-litre bio-digesters over a 30-day period to examine the process. A mixture of three litres of slurry and water was added to the digesters, and temperature and pH levels were monitored every three days. Samples from the digesters were taken to assess bacterial growth, and bacterial species were identified using standard microbiological methods. Additionally, the plasmid profiles of the isolated bacteria were determined, while a proximate analysis of the digester contents was performed before and after digestion. The temperature within the digesters ranged from 24.1°C to 36.7°C, while the pH varied between 5.5 and 8.0. The bacterial count increased over time in CD and the CD mixture, while it decreased in RH alone. Eight bacterial species were isolated, including Proteus vulgaris and Escherichia coli, with plasmids detected in four species, indicating their genetic potential for effective biogas production. The co-digestion of RH and CD yielded the most biogas (5200 cm³), followed by CD alone (4500 cm³), while RH produced the least (110 cm³). The gas from the CD mixture contained 83.2% methane (CH4), whereas RH alone produced only carbon dioxide (CO2). The findings suggest that combining cow dung with rice husk is an efficient, low-cost method for generating biogas, providing a solution to both waste management and renewable energy production.