Effect of C/N ratio variations on the capability of microbes from Muara Karang river sediment in the production of biogas and identification using VITEK 2

Gas is one form of microbial metabolism products that can be identified as biogas, one example of biogas is methane gas. The production of methane gas by bacteria occurs through methanogenesis with three stages, namely hydrolysis, acetogenesis, and methanogenesis. These processes are generally performed by bacteria in an anaerobic environment. The Muara Karang River sediments contaminated with organic matters and having low oxygen are potential as the habitat for anaerobic microbes with methanogenesis ability. The ability of such sediment microbes in biogas production was tested by inoculating Muara Karang sediment in a Methanogen Enrichment Barker broth medium with variations of C/N ratio using glucose as the carbon source to analyze the biogas production. The parameters measured were the total carbon, the total nitrogen, and the biogas volume. Two isolates were obtained, namely isolate I and isolate II. These isolates were then identified by the VITEK 2 compact equipment. The result showed that C/N ratio of 25:1 could produce the highest biogas volume. Isolate I was identified by the VITEK 2 equipment as Methylobacterium spp. from methanotroph group bacteria and isolate II was identified as Dermacoccus nishinomiyaensis.