Study of C/N/P concentration and incubation period of hydrogen producing bacteria (Enterobacter aerogenes) on palm oil mill effluent

Palm Oil Mill Effluent (POME) contains organic substances that support the habitat of hydrogen-producing anaerobic bacteria and a by-product of palm oil processing with potential environmental pollution if disposed directly due to its high Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), and Total Suspended Solid (TSS) value. One of the approaches of POME treatment is dark fermentative which has ability of producing biohydrogen as green and sustainable source of energy in addition solving waste problems. This research evaluates the effect of concentration of carbon/nitrogen/phosphorus (C/N/P) in enhancing the production of biohydrogen. One of the main factors affecting bacteria productivity and total hydrogen yield is the source of C/N/P and its concentration. The medium was consist of sterilized POME neutralized to pH 7, fructose as organic carbon source (25000, 10000, and 5000 ppm), NH4Cl as inorganic nitrogen source (2500, 1000, and 500 ppm), KH2PO4 as inorganic phosphorus source (250, 100, and 50 ppm) and 5% (v/v) inoculum bacteria with incubation (24-96 hours, anaerobic, without agitation, 37°C). Microorganisms were mesophilic bacteria, Enterobacter aerogenes, with capability of producing biohydrogen using a complex medium, is a novelty. Method for determining biohydrogen is Gas Chromatography-TCD. The optimal biohydrogen produced was achieved by adding fructose: NH4Cl:KH2PO4 (5000:500:50 ppm) with respective results of incubation periods 24, 48, 72 and 96 hours 1,91%, 12,27%, 18,16%, and 20,53% compared to other variations. COD reduction after POME treatment was 89,92% from 31750 to 3200 ppm at C/N/P concentration 5000:500:50 ppm.