Study On The Fermentation Of Lignocellulose

With the advent of energy crisis,the global environmental pollution is increasingly serious,we need to seek new sources of energy to replace oil.Biological fuel ethanol and butanol as a new type of biological energy were to be attention and research.In the past,the research on biological fuel ethanol and butanol on the starch,honey and other food crops to fermentation.With the advent of the world food crisis,We need to choose renewable resource as an object of fermentation to ease food crisis.Lignocellulose is the most abundant renewable resources in the world,After pretreatment,hydrolysis of lignocellulose,generation of reducing sugars that can be utilized by microbial fermentation,in order to produce ethanol and butanol.So it can ease the energy crisis and food crisis,it can make use of lignocellulose resource.This topic uses lignocellulose(smashed straw)as raw materials.The content was that analysed the composition of the raw material,and the discussion cellulose enzyme hydrolysis conditions,it choose appropriate hydrolysis conditions,and then it proceed microbial fermentation.The topic selected yeasts and acetone butanol carboxylic acid bacteria for ethanol and butanol fermentation.Through detoxification treatment increase the fermentation product.It mainly consists of the following parts.Part 1,To analyze the composition of the raw material composition.Lignocellulose is mainly composed of cellulose,hemicellulose and lignin of three parts,pretreatment method is different,material is different,the content of these three components are also different.Ultrafine comminution of rice which contains cellulose of 24.8%,hemicellulose contains 21%,and acid detergent lignin contains 10.9%.Part 2,To explore the optimal hydrolysis conditions of Cellulase.The single factor experiment was conducted to research the influence of substrate concentration,temperature,pH,and enzyme-substrate on enzymatic hydrolysis,so as to confirm the best condition for single factor experiment.We get a result by choosing orthogonal experiment,combined with the impact of the subsequent fermentation,the optimum hydrolysis conditions is temperature of 50 ?,pH 5,and substrate concentration was 10%,and the hydrolysis time was 24 h,and the ratio of enzyme to substrate was 6%.Part 3,The fermentation of fuel ethanol.It conditions a result through the single factor experiments of yeast cells fermentation,The best conditions of yeast cells fermentation was that temperature is 30,inoculation quantity is 9mL,the growth of yeast pH is 5,fermentation time is 48 hours.To increase the concentration of reducing sugars by concentration,the fermentation results was that inhibitor concentration increased in the concentrated solution,which it effects of microbial growth,so it can hindered the yeast fermentation,Although the sugar utilization increased by 10%,and the ethanol yield was down 18.7%.The maximum yield of ethanol was 2.17 g through detoxification treatment,the theoretical yield was 2.4g,the yield reached 90%,in which the best effect was activated carbon.Part 4,It researched butanol fermentation.Acetone butanol carboxylic acid bacteria is strict anaerobic microbes,it needs to manufactue anaerobic environment by filling nitrogen.Directly to butanol fermentation,butanol yield is only 4.7 g/L,ABE total volume was 8.14 g/L,butyl alcohol conversion rate is 12%,sugar total solvent conversion rate was 21.9%.After detoxification treatment,solvent butanol yield and total solvent yield were improved.When used the method of 0.1% sodium sulfite,butanol yield was 6.11 g/L,ABE total volume was 9.24 g/L,butyl alcohol conversion rate increased to 17%,total sugar fluxing agent conversion rate was 25.7%.Activated carbon processing,butanol production was 7.86 g/L,total solvent was 14.12 g/L,butyl alcohol sugar conversion rate increased to 19.9%,sugar total solvent conversion rate was 30.8%.The rate of sugar use can reach 90% in ethanol fermentation,The rate of sugar use can reach73% in butanol fermentation,biological ethanol fermentation on the utilization rate of lignocellulose was high.