Study On Parameter Of Solid-state Fermentation For Producing Single Cell Oil And Nutritional Value Of Fermented Product

In this study, the parameters of solid-state fermentation on agricultural byproducts for producing single cell oil (SCO) were explored. Phanerochaete chrysosporium, Trichoderma reesei, Aspergillus niger and Red yeast were used. Meanwhile, the nutritional value of the fermented product was evaluated by a digestion trial of growing pigs.Experiment1Optimal parameters for production of microbial oils fermented by multi-strains with rice bran and wheat branThe aim of this study was to improve the degradation rate of non-starch polysaccharides and the amount of microbial oils deposition in the mixed solid-state fermentation. Several single factor trials and an orthogonal design were carried out to explore the optimal fermentation conditions. The results showed that seeds culture times were48h (Phanerochaete chrysosporium),96h (Trichoderma reesei),12h (Aspergillus niger), and20h (Red yeast) respectively.20%defatted rice bran,60%wheat bran,13%rapeseed meal and7%other material consisted the optimal fermentation substrate. The ration of1:5:1:5for Phanerochaete chrysosporium Trichoderma reesei:Aspergillus niger:Red yeast,5%inoculated amount,1:1.1of material to water ratio,4days of fermentation time and28℃of fermentation temperature, were the optimal fermentation conditions. Under the optimal fermentation conditions, the amount of SCO deposition reached7.24%DM of fermentation products, and the total energy of fermentation substrate enhanced from15.46MJ/kg DM to18.24MJ/kg DM.Experiment2The assessment of nutritional value on the fermented product in growing pigsThe aim of this study was to produce solid-state fermented product and to evaluate the nutritional value of the product of growing pigs. A total of24DLY crossbred pigs with average initial BW of36.9±0.9kg were randomly allocated to three treatments, eight replicates per treatment and1pig per replicate. The diets were a basal corn-soybean-based diet or the basal diet replaced by20%non-solid-state fermented substrate (NSSF) or20%solid-state fermented product (SSF). The result showed that the nutrition profile of the solid-state fermented product was similar to that of the laboratory fermentation, the contents of reducing sugar, crude lipid, crude protein were1.67%,6.89%and22.34%(P<0.05) respectively. Compared to the NSSF, after solid-state fermentation, the apparent digestibilities of crude lipid, fiber, neutral detergent fiber, acid detergent fiber and energy were significantly increased (P<0.05). The digestible energy of the NSSF was only9.55MJ/kg, but the fermentation product digestible energy increased to11.69MJ/kg.In summary, the mixed strains solid-state fermentation can effectively degrade the non-starch polysaccharides of agricultural byproducts, benefit the deposition of microbial lipid, increase the content of crude protein, reducing sugar and energy, significantly improve its nutritional value and digestibilities of nutrients.