An Evaluation of Palm-Oil Milling Effluent Treatment by Fermentation to Produce Animal Feed Protein

Abstract

Present disposal methods of palm-oil milling effluent result in the pollution of the majority of the Malaysian rivers. A system ('Malima') to treat the effluent based on a continuous fermentation has been developed which produces a high protein fungal biomass, as an animal feed, to offset treatment costs. The viability of the 'Malima' system was found to depend on the value of the fungal biomass as an animal feed. Therefore the evaluation of the fungal biomass as a protein ingredient centred on animal feeding trials with rats and poultry and supportive trials with poultry and mice; these together with chemical analyses constituted the practical research. In the assessment ten crucial factors were identified in the evaluation of the fungal biomass as an animal feed and the appraisal of the economic viability of the 'Malima' system was based on pilot trials carried out with the prototype erected in Malaysia. The fungal biomass was shown to be an effective protein ingredient for poultry and could be successfully incorporated up to 20% by weight in the diet as a partial replacement for soyabean meal, both in Malaysian and U.K. standard formulations, The economic evaluation indicated that as a complete effluent treatment system producing animal feed, the 'Malima' process was a viable investment in payback years and discounted cash flow yield terms, in Malaysia and U.K. In Malaysia for a variety of local and commercial reasons the 'Malima’ process was not implemented during the period of this research, but, the proven potential applications of such a system remain attractive both to alleviate pollution and enhance the protein supply.