Research On Production Of Bio-feedstuff With Rich Peptide From Rapeseed Meal By Mixed Solid-state Fermentation

Our country has a big problem in shortage of good protein feedstuff, but rapeseed meal which contains 35 percent of protein is not utilized effectively. Maybe, there are three reasons. The first reason is true protein in rapeseed meal is not much enough; the second is there are many kinds of anti-nutritional factors such as glucosinolate; the third is protein in rapeseed meal is too big to be absorbed. In this paper, I do a research to find the best stains which can solve three problems above mentioned. Based on studies of producing bio-feedstuff with rich peptide from rapeseed meal by solid state fermentation, scale-up production, estimation of production and animal feeding researches were studied.Single, two, three and four strains solid fermentation researches are studied to find the best stains, the result is that group of Bacillus subtilus(Bs) and Geotrichum candidum(Gc) is the best stain.The content of true protein, glucosinolate and peptide in the fermentation product is 35.6%、27.4μmol/g and 113.2 mg/g.So the two strains can be selected to produce high quality protein feedstuff from rapeseed meal by solid state fermentation.Effects of inorganic salt, nitrogen source, complement and solid-liquid ratio in culture medium were studied by single factor tests of solid-fermentation with optimal mixed strains. The composition of culture medium was optimized by orthogonal experiment, which taken contents of peptide as index. In culture medium CaCl2 is best inorganic salt; NH4CI is best nitrogen source; no complement has remarkable improvement on fermentation effect. The composition of optimal culture medium was 0.1% of CaCl2,1.5% of NH4Cl and 1:1.2 of solid-liquid ratio. The contents of peptide in fermentation product would reach to 12.81% with optimal culture medium.Taking the contents of peptide as index, the conditions of fermenting rapeseed meal to produce peptide by Geotrichum candidum and Bacillus subtilus were studied. Plackett-Berman experiment was done to find out significant factors including Sterilization-none Sterilization, fermentation temperature fermentation time. The best conditions of fermenting were researched by single factor tests and response surface methodology (RSM).The result is that fermentation temperature 35.68℃, inoculation 18.68%, fermentation time 4.25 d. Under such conditions the content of peptide in the product would reach 157.79 mg/g.The optimized fermentation conditions of simulation production of scale-up were studied. The results show that:fermentation substrate is sterilized, the rapeseed meal crush for the 60 mesh size, seed liquid form seeds. Under the optimal conditions true protein, the content of glucosinolate and the content of peptide in the fermentation product would reach 41%,22μmol/g and 65 mg/g. The total amount of amino acids in fermented product increases 24.07 percent, but has not reach the content rated by FAO.The feeding formulation of white mouse, rapeseed fermentation product takes place of normal feeduff in part. Growth of mouse and protein utilization with fermentation product is close to mormal feeduff. We find out the fact the injury to liver, kidney and thymus by fermentation rapeseed is much lighter than the injury by common rapeseed with pathological section.