TREATMENT AND VALORISATION OF PALM OIL MILL EFFLUENT (POME) THROUGH PRODUCTION OF MICROBIAL BIOMASS.

TREATMENT AND VALORISATION OF PALM OIL MILL EFFLUENT (POME) THROUGH PRODUCTION OF MICROBIAL BIOMASS.

ABSTRACT

Palm oil mill effluent (POME) is high strength wastewater capable of polluting the environment. It is produced in large quantities in Nigeria and is amenable to microbial degradation. The use of POME as microbial fermentation media is largely due to the fact that POME contains high concentrations of carbohydrates proteins, and nitrogenous compounds in addition to minerals. The POME used in this study contained 114800 mg/l chemical oxygen demand (COD), 76000 mg/l total solids (TS), 44000 mg/l total suspended solids (TSS), 32000 mg/l total dissolved solids (TDS) and 3580 mg/l total lipids. Yeasts isolated from stale POME, POME dump site and palm wine were used to treat POME and to produce yeast biomass. Seven yeasts were isolated from palm wine (L31, V42 and V42), stale POME (TWDC and TWC) and POME dump site (TMCC and SP5). Based on their colonial and physiological characteristics the isolates were identified as Saccharomyces species (L31 and V42), Pichia sp (V45 and SP5) and Candida sp (TMCC, TWC and TWDC). These isolates were screened for their ability to produce biomass and degrade POME by reducing the COD of POME. POME was used as sole source of carbon and nitrogen and the fermentation was carried out at 150 rpm, 28 ± 2oC using an inoculum size of 1ml of 106 cells for 25 ml of fermentation medium (POME).  prOut of the seven yeast isolates screened for biomass production, isolate L31 gave the highest biomass yield of 4.42 g/l as well as the highest COD removal of 83% after 96 h and was selected for optimization studies on microbial biomass production. The optimal conditions for microbial biomass protein production were 100% (undiluted) POME concentration, C: N ratio of 10:1 and peptone as nitrogen supplement. The amino acid profile of final microbial biomass protein of L31 showed that it is rich in all essential and non-essential amino acids and could be used in the enrichment for the supplementation of animal feeds.