Technology optimization of multi-strains multi-step solid-state fermentation of fruit residue to produce cell protein feeds

The condition of multi-strains multi-step solid-state fermentation of fruit residue to produce cell protein feeds was studied. Taking fruit residue as the main raw material, bran, soybean meal, carvings and others as accessories, through the study on multi-strains(Aspergillus niger, Candida utilis, Candida tropicalis and Saccharomyces cerevisiae) inoculation and cultivation methods, inoculum, optimum temperature for fermentation, co-fermentation time, solid-liquid ratio and material pH, the optimized multi-strains multi-step solid-state fermentation of fruit residue to produce cell protein feeds production process was obtained. By single factor test and orthogonal test, the optimum fermentation conditions were obtained as follows: material quality/water volume 60%, initial pH 5.5, temperature 30℃, inoculum of Aspergillus niger 7.50%, inoculums of compound 10%, A. niger was inoculated in the early stage of fermentation, compound liquid yeast was inoculated after fermentation for 24h, co-fermentation time 72h. Under the optimized condition, the crude protein in end product increased from 4.97% to 27.6%, increased by 22.63%, which achieved the high quality protein feed standard.