Studies On Degraded Conditions Of Sesame Cake And Its Influential Factors

Oil waste are the by-products when the plant seeds or fruits were squeezed to produce the oil.Sesame cake is one common oil waste which is rich of crude proteins,crude fats,starch,minerals and vitamins.If sesame cake can be effectively used,the environmental pollution problems caused by industrial production would be reduced;meanwhile the economic benefits and the development of oil industry should be promoted.In this study,the microbial fermentation technology was used to degrade the sesame seeds with different residual oil contents by the compound bacteria containing two strains.The effects of the different residual oil contents on the degradation of the protein were compared,and the differences of products after the sesame cake fermentation were analyzed.Based on the comparison of the degradation efficiency on crude proteins and crude fats of five kinds of sesame cakes,one which is the most beneficial to the compound strains was selected as the substrate.The validating experiment was carried out in the shake flasks,50 L liquid deep fermentation and 500 L pilot test.One experimental strain which efficiently degrades the sesame proteins was screened by our team and identified as the genus Bacillusion LQ,and the other one which efficiently degrades the sesame fats was identified as the fungus of Aspergillus YF.The main results are concluded as follows:The substance strain LQ degrading most efficiently is cake 5,since the degradation rate of the protein was best.The protease activity was 567.93 U / mL,the degradation rate of the proteins was about 51.89%,the conversion rate of the amino acids was 13.27%,the conversion rate of organic acid was 0.11%.With the residual oil contents in sesame cake reduce,the content of crude proteins will be improved,and the protease activity will be improved accordingly.So sesame cake 5 will be used as the optimum fermentation substrate.The optimum culture medium and culture conditions of the mixed bacteria LQ and YF were determined as follows: 1% soluble starch,12% sesame cake,0.1% potassium dihydrogen phosphate,0.1% calcium chloride,0.05% magnesium chloride,initial pH 7.0,the inoculation ratio of strain LQ and YF 2: 1,inoculation volume 5%,temperature 37?,fermentation time 48 h,rotation speed 180 rmp.Under this condition,the degradation rate of crude proteins was 67.25% and the crude fats was 65.20%.Based on the flask conditions,the fermentation was investigated in a 50 L fermenter.The fermentation conditions were optimized by the orthogonal test with the degradation rate of crude proteins and crude fats in sesame cake 5 as the indexes.The optimum conditions are temperature 37?,rotation speed 180 rpm,ventilation rate 150L/h.The results showed that the degradation rate of crude proteins was about 69%,the degradation rate of crude fats was about 65%,and the yield of crude oil was about 50%.Furthermore,the efficiency is much higher in 500 L fermentation.The degradation rate of crude proteins is 83.34%,degradation rate of crude fats is 75.01%.