ISOLATION OF Aspergillus oryzae AND SINGLE CELL PROTEIN PRODUCTION BY GROWN ON COFFEE CHERRY HUSK AND SAWDUST

Abstract

The rising global population pressure generates challenges to fulfill food requirements for the coming generations in adequate amounts. This suggests that the human population cannot continue to be entirely dependent on crops, animal husbandry and fisheries for food. Instead, efforts should be made to enhance the production of other potential alternative sources of food. To this end the current study has been undertaken to evaluate the production of single cell protein (SCP) from Aspergillus oryzae using coffee cherry husk and sawdust, to analyze the nutritional composition of the Aspergillus oryzae biomass produced and to determine the residual nucleic acid content of the biomass before and after nucleic acid reduction. Soil samples, coffee cherry husk and sawdust were collected from Southern Nations Nationalities Peoples Regional State, Gedio Zone, Dilla. Identification of Aspergillus oryzae was done using Aspergillus flavus and parasiticus agar (AFPA) to differentiate the isolates from Aspergillus flavus and Aspergillus parasiticus depending on the fungal colony reverse colors on plates. Two types of sterilized growth substrates, coffee cherry husk and sawdust, were transferred in to two sterile petri-dishes and inoculated with Aspergillus oryzae suspension containing 106-107 spores/ml and incubated for seven days. To collect the biomass, 1gm fermented substrate from each petr-dish transferred to pre-weighed centrifuge tubes and 5ml of sodium sulphate (150 gm 1-1) were added to each tube. The tubes were centrifuged at 12000 rpm for 15 minutes. At the end of centrifugation, the fungal biomass with lower density than the substrate floated while the substrate settled to the bottom. The biomass were dried and grinded using a mortar and pestle. Three types of buffers were used for the extraction of total proteins from Aspergillus oryzae. The collected data were subjected to Analysis of Variance (ANOVA) with three replications using Statistical Analysis System (SAS) Version 9.0. The highest amount of protein (57.1mg), was recorded from Aspergillus oryzae grown on 60% CCH + 40% SD alone. Whereas the least amount of proteins were obtained from grown substrate 100% SD (24.9mg). 60% CCH + 40% SD is the appropriate combination that produce high amount single cell protein from Aspergillus oryzae