Production of single cell protein from cereal by-products

Abstract

The single cell protein (SCP) which can be produced by culturing cellulolytic fungal mycelium in media containing cereal by-products (wheat bran, rice husks and corn cobs) depends to a large extent on the cellulase enzymes of the fungus. Several factors affecting the production of single cell protein were studied and the optimum conditions were determined. The optimum initial pH values of the growth medium for the production of SCP were 2 and 4 for Aspergillus niger and Aspergillus terreus, respectively. Wheat bran was the best cereal by-product for SCP production and compared favourably with glucose as a carbon source for SCP production by A. niger. Milling cereal wastes to fine particles tended to enhance the production of SCP. Ammonium chloride was the best nitrogen source. Removing the organic nitrogen source from the ammonium sulphate medium decreased the protein content in the residual biomass. Concentrations of 1·5 and 2·0% of wheat bran in the growth media were recommended for the production of SCP by A. terreus and A. niger, respectively. The optimum incubation temperatures were 25 and 30°C for A. niger and A. terreus, respectively. Protein content of the residual biomass increased when the growth medium was aerated. About 40% protein was found in the residual biomass of A. niger and A. terreus grown on wheat-bran medium. The amino acid profile of the biomass showed the presence of all essential amino acids except methionine.