Production of mini-food by Aspergillus niger, Rhizopus oryzae and Saccharomyces cerevisiae using orange peels

In this study, an evaluation of the possible use of orange peels (OP) as substrate to produce single-cell protein and mini-food by Aspergillus niger, Rhizopus oryzae and Saccharomyces cerevisiae was performed. The role of several fermentation parameters including moisture level, bed loading, initial spore count, incubation period, agitation rate, initial pH, incubation temperature, and carbon and nitrogen nutrition was investigated. Efficiency of 0.4 M NaOH, 0.3 M NaOH and Tris-HCl buffer (pH 9) for extraction of protein from the formed biomass of A. niger, R. oryzae and S. cerevisiae respectively, was demonstrated. Profiles of essential amino acids of the single-cell protein (SCP) compared favourably with FAO standards. RNA levels in the yielded protein were successfully reduced to 1.7%, 1.9%, and 1.4% (w/w).