The Optimization Of Butanol Fermentation Process Of Two Kinds Of Clostridium And Kinetic Studies

Butanol is an energy source with high internal energy and calorific value that can be mixed with gasoline at a higher ratio.The production of butanol by biofermentation will not only help promote energy diversification,but also help us to get rid of the heavy reliance on traditional fossil fuels,and it will also reduces greenhouse gas emissions and relieve pressure on the environment.However,there are still many problems to be solved in the actual production process,such as the toxic effect of the target product on the strains and the difficulty in separating the fermented product.In response to these problems,this paper first used response surface methodology to optimize the preparation conditions of Clostridium acetobutylicum and Clostridium beijerinckii sorbent,and through the solubility of butanol in the organic phase,the maximum partition coefficient was selected from oleyl alcohol,n-octanol,ethyl oleate,oleic acid and butyl acetate as an extractant for extracting fermentation.The results showed that in the preparation of strains of adsorbents,when the amount of sodium alginate was 0.55 g,the ratio of dispersant to strain solution was 1.05,and the concentration of calcium chloride was 8.24 g/L,Calcium alginate sorbent with Clostridium acetobutylicum and Clostridium beijerinckii has maximum adsorption performance;among the five organic solvents,since n-octanol has the highest partition coefficient of butanol and the partition coefficient of ethanol and acetone is low,n-octanol is selected as the extractant,and further The study found that the ratio of 5:1 aqueous phase to organic phase is the best ratio.Secondly,the fermentation process was optimized by examining the effect of heat shock on Clostridium,and the initial yeast extract concentrations in different proportions(0.0 g/L,0.01 g/L,0.05 g/L,0.1 g/L,0.15 g/L),different ratios of glucose concentration(40 g/L,50 g/L,60 g/L,70 g/L),different pH(3.5,4.0,4.5,5.0,5.5,6.0,6.5)Clostridial fermentation results.The optimized results can be achieved when the seed fluid was heat shocked,the initial yeast extract concentration was 0.1 g/L,the glucose concentration was 60 g/L,the initial pH of Clostridium acetobutylicum and Clostridium beijerinckii was 5.5 and 5.0,respectively.After optimization of the coupled fermentation of immobilized and immobilized Clostridium,the total butanol concentration of the confluent fermentation layer remained stable at about 12 g/L after stabilization.Finally,the growth kinetic model for the continuous fermentation was established using Logistics equation.According to the relationship between glucose concentration and time,the kinetic model for continuous fermentation of substrate was established based on the principle of matrix equilibrium using the Luedeking-Piret equation.The above model was verified by showing that the experimental value and the model value matched well.The model can be used to predict the growth of bacteria,substrate consumption and product formation during the continuous fermentation coupling with extraction of butanol for Clostridium acetobutylicum and Clostridium beijerinckii.