This study analyzed the anaerobic co-digestion of Inoculum (I), Rubber Plant Effluent (RPE) and Gliricidia leaves (GLS) at different mixing ratios for the simultaneous production of methane and organic fertilizer. The results were analyzed for volatile fatty acids, pH, C/N ratio, and methane production. The organic quality of the substrate mixture before and after anaerobic digestion was analyzed for organic carbon, Kjeldahl nitrogen, potassium, and phosphorus content. The study concluded that the inoculum, Rubber Plant Effluent (RPE), and Gliricidia leaves (GLS) mixed in the ratio of 10:2:2 showed higher methane production than other experiments conducted at different mixing ratios. The nitrogen, Potassium and phosphorus content of the substrates are increased after anaerobic digestion. However, the organic carbon content in the substrate decreased in all experiments. This research recommends the planting of rubber trees and Gliricidia maculata to promote economic development in Mauritania. Keywords: Biogas production; Gliricidia leaves; Methane; Rubber Plant Effluent; Organic Manure

This study analyzed the anaerobic co-digestion of inoculum (I), rubber plant effluent (RPE) and Gliricidia leaves slurry (GLS) at different mixing ratios for the simultaneous production of methane and organic fertilizer. The results were analyzed for volatile fatty acids, pH, C/N ratio, and methane production. The organic quality of the substrate mixture before and after anaerobic digestion was analyzed for total organic carbon, total nitrogen, potassium, and phosphorus contents. This study concluded that the inoculum, rubber plant effluent (RPE), and Gliricidia leaves slurry (GLS) mixed at the ratio of 10:2:2 showed higher methane production than other experiments conducted at different mixing ratios. The nitrogen, potassium, and phosphorus contents of the substrates were increased after anaerobic digestion. However, the organic carbon content in the substrate decreased in all experiments. This research recommends the planting of rubber trees and Gliricidia maculata to promote energy sustainability and the socio-economic development of Mauritania.