Study On The Efficacy And Mechanism Of Enhancing Even Carbon VFAs By Anaerobic Fermentation Of Peanut Meal

Organic solid waste peanut meal is rich in nutrients such as protein and polysaccharides,and has huge resources.It can be processed by anaerobic fermentation acid production process to obtain high value-added intermediate product volatile fatty acids(VFAs).Peanut meal is mainly produced by even carbon volatile fatty acids(ECFA).ECFA has important practical value.It can be used as an additional carbon source for the nitrogen and phosphorus removal process of sewage,to produce bioenergy and as a raw material for the synthesis of PHAs.The subject of the project is to enhance the efficiency of anaerobic fermentation of peanut meal to produce ECFA.First,a sequential batch anaerobic fermentation test device is used to examine three enhancement methods(alkaline initial p H,yeast addition and Bacillus subtilis addition)on the effect of anaerobic fermentation of meal on the efficiency of ECFA and its mechanism,comprehensively determine the optimal enhancement method.Then based on the CSTR anaerobic fermentation acid production process,the effects of different influent p H conditions and optimal enhancement methods on the efficiency of peanut meal anaerobic fermentation ECFA were studied.Studies on the effects of three fortification methods on the efficiency of anaerobic fermentation of peanut meal to produce ECFA show that: The three enhancement methods can effectively improve the efficiency of peanut meal anaerobic fermentation to produce ECFA.ECFA/VFAs are above 95%.The main components of ECFA are acetic acid and n-butyric acid.Yeast and Bacillus subtilis can significantly increase the rate of ECFA produced in the initial fermentation,Of which the best way to strengthen is yeast.When the yeast dosage ratio is 0.20 g/g,the average VFAs concentration reaches a maximum of 8 030.44 mg/L.When the yeast dosage ratio is 0.15 g/g,the average acetic acid concentration and the average ratio of acetic acid in the stable stage,The highest reached 4 923.33 mg/L and 63.13% respectively.The three fortification methods can effectively promote the dissolution of SCOD,soluble protein and soluble polysaccharides.Microorganisms are the first to use soluble polysaccharides for acid production.Among them,the utilization rate of soluble polysaccharides in alkaline initial p H is the lowest,and that of yeasts is the highest.The analysis of the mechanism of anaerobic fermentation of peanut meal by anaerobic fermentation by yeast showed that,The hydrolysis process of yeast dosage ratio of 0.00,0.05,0.15 and 0.25 g/g conforms to the first-order reaction kinetics equation.The protein hydrolysis rate of yeast dosage ratio of 0.10,0.20 g/g and 0.25 g/g is improved.The ECFA production process of yeast with a dosage ratio of 0.00 and 0.20 g/g conforms to the Logistic equation model.The maximum specific acid production rate of yeast with VFAs and acetic acid with a dosage ratio of 0.15 and 0.20 g/g is improved.The yeast-dosed ratio of 0.10 g/g for producing VFAs and the process of producing acetic acid had the highest inhibitory concentration of ammonia nitrogen.The response surface method analysis predicted that when the yeast dosage ratio was 0.20 g/g and the fermentation time was 10 days,the effect of producing ECFA was optimal.Study on the effectiveness of anaerobic fermentation of peanut meal CSTR to produce ECFA:(1)Under different influent p H conditions,the average value of ECFA/VFAs is above 96%.The main components of ECFA are acetic acid and n-butyric acid.Microorganisms have a high utilization rate of soluble proteins and soluble polysaccharides.Microorganisms take advantage of solubility first Polysaccharides.The effect of producing ECFA is best when the influent p H is 9,the ratio of VFAs/SCOD is higher,and the average concentration of VFAs is 8 588.48 mg/L.Changing the p H value of the influent has little effect on the ECFA/VFAs and the type of acid production.The proportion of acetic acid in the continuous flow stage has a relatively large change compared to the start-up stage.(2)Under the condition of yeast addition,the average value of ECFA/VFAs is above 98%,and the main components of ECFA are acetic acid and n-butyric acid.The proportion of acetic acid,the concentration of acetic acid and the growth rate of VFAs increased significantly during the start-up period,and the concentration of soluble protein and soluble polysaccharide increased significantly.In the continuous flow stage,the acid-generating efficiency decreased,and the average percentage of acetic acid,the average concentration of acetic acid and the average concentration of VFAs in the yeast-dosing group decreased compared with the blank control group.