A Study on Temperature Variations, PH Changes, and Biochemical Characterization of Bacteria in Cow Dung Substrates for Biogas Production

This study aims to explore the potential of cow dung as a substrate for biogas production, focusing on the impact of temperature, pH variations on biogas yield and the identification of key bacteria involved in the biogas production. Biogas production was generated using the downward displacement method of water. Temperature readings were taken daily and pH of the cow dung substrate was measured before and after the digestion. Bacteria involved in biogas production were isolated and identified using Gram staining. The results showed that biogas production was significantly higher in weeks 3 and 4, with yields of (2360.00±183.60mL) and (3223.00±1377.00mL) at temperatures of 34.0±1.0°C and 36.5±1.5°C, respectively with no significant difference. However, the biogas yield in weeks 1 and 7, were (130.00±34.64 mL) and (70.00±20.00 mL) at temperatures of 26.5±1.0°C and 26.2±1.5°C, respectively, was significantly lower at(p < 0.05) compared to weeks 3 and 4 (Table 1). The pH decreased slightly from 7.827±0.093 before digestion to 7.227±0.04 after digestion, but this change was not statistically significant. Gram staining identified Bacillus subtilis and Bacillus cereus as the primary bacteria involved in the biogas production process. In conclusion, the study showed that temperature significantly influences biogas production from cow dung, with optimal yields observed at higher temperatures and the presence of Bacillus subtilis and Bacillus cereus, contributes to the efficiency of the biogas production process. Further research should focus on optimizing temperature control during anaerobic digestion and exploring co-digestion with other substrates.