| At present,the excessive utilization of fossil energy has brought serious damage to the natural environment,such as acid rain,haze and other climate disasters are getting worse.At the same time,fossil energy,as a non-renewable resource,is decreasing with the large-scale exploitation and application.Therefore,it is particularly important to find and utilize an environmentally friendly renewable energy source as an alternative energy source for fossil materials.Biomass is the most abundant renewable resource known,and its source is particularly wide,including crop stalks,forestry waste,and agricultural waste and so on.In the complex composition of biomass,lignocellulose is the most important component and can account for more than 60% of the biomass dry weight.At present,the bio-refinery technology using lignocellulose as raw material has achieved relatively rapid development,and has extended the production of more types of bulk chemicals such as fuel ethanol and butanol.Among these biomass resources that can be acquired on a large scale,cow manure is the most important waste in the aquaculture industry,and it is also an important raw material with a relatively rich cellulose content in the biorefinery industry.At present,the main application of cow manure is mainly focused on the anaerobic fermentation production of biogas and the simple utilization of organic fertilizers.These simple application processes of cow manure did not fully reflect its application value.In this paper,combined with the current major demand for bio-energy,the potential of cow dung in the induction of cellulase and the production of lignocellulose ethanol is emphatically studied.In this paper,combined with the current major demand for bio-energy,the potential of cow manure in the induction of cellulase and the production of lignocellulose ethanol is emphatically studied.In the process of lignocellulosic ethanol production,cellulase hydrolysis is the most critical step in the degradation of lignocellulosic materials into fermentable sugars.Therefore,the efficient production of cellulase has a significant impact on reducing the biorefining cost of lignocellulosic biomass.This research paper focused on the biological processes induced by cow manure in cellulase expression of Penicillium oxalicum,the production of cow manure fuel ethanol,and the construction of high-yield cellulase strains of Penicillium oxalicum.The main results are as follows:?: Induction of Cellulase Expression of Penicillium Oxalate by Cow ManureThe cow manure produced before and after the production of biogas was replaced with the delignification xylose residue in the enzyme producing medium,and prepared into the cow manure medium before biogas production and the cow manure medium after biogas production,and compared with the existing enzyme producing medium in the laboratory.Using Penicillium oxalicum wild strain 114-2 and its genetically engineered strains RE-8,RE-10 and RBB1-10 to test the efficacy of cow manure on inducing cellulase expression in strains.The result of enzyme activity assay showed that the medium prepared with the cow manure before and after biogas production as the main raw material had obvious induction effect on the cellulase expression of Penicillium oxalicum.?: Effect of Penicillium oxalicum cellulase on ethanol fermentation of cow manureThe hydrolysis of corn straw,cow dung before biogas production,and cow dung after biogas production are used as main raw materials.The hydrolysate is used as the fermentation medium of Saccharomyces cerevisiae to produce cellulosic ethanol.The results showed that among the three cellulase systems,the commercial cellulase SN-1(produced by Penicillium oxalinate),the Penicillium oxalicum RBB 1-10 cellulase,and the mixed enzyme of two cellulases,the use of commercial cellulase SN-1 to hydrolyze lignocellulosic raw materials to produce sugar and thereby produce ethanol has a better conversion rate.Among them,the ethanol conversion rates of corn straw,cow manure before biogas production,and cow manure after biogas production were 67.49%,65.70%,and 49.02%,respectively.?: Batch hydrolysis of cellulase by Penicillium oxalicumBatch hydrolysis and fermentation of pretreated lignocellulosic materials can effectively increase the yield and conversion rate of ethanol.When the final concentration of pretreated hydrolyzed substrate was 15%,the ethanol yield of corn stover in the single batch of hydrolysis and batch hydrolysis fermentation was 45.49 g/L and 44.59 g/L,respectively;The ethanol production of cow manure before production of biogas was 18.76 g/L and 22.29 g/L,respectively;The ethanol production of cow manure after production of biogas was 8.12 g/L and 15.8 g/L,respectively.The ethanol conversion rate of corn stover in single batch hydrolysis and batch hydrolysis fermentation was 68.82% and 67.46%,respectively;The ethanol conversion rate of cow dung before production of biogas was 43.39% and 51.55%,respectively;The ethanol conversion rate of cow dung after production of biogas was 21.11% and 41.08%,respectively.Ethanol production and conversion rates have improved significantly?: The effect of terminator on the function of cellulase regulatory factor of Penicillium oxalicumThe promoter and terminator regions in the gene expression module are important factors affecting the cellulase gene expression activity.In particular,there have been few reports on the screening and characterization of highly active terminators that have an effect on enhancing the expression of genes.To construct a cellulase gene expression module with higher expression activity.In this study,two(TD,Teg I)and five(Tbgl II,Tcbh I,TD,Teg I,TGpd A)terminators were screened and obtained based on transcriptomic analysis under various conditions of Penicillium oxalicum.Confirmatory analysis of recombinant expression of clr B and xln R encoding key activators of Cellulase.It was found that the FPA activity of recombinant strain YC-1 reached 1.55U/m L,8.56 times that of the original strain.At the same time,the use of the cbh I terminator region in the strain G-75 in the xln R expression cassette resulted in a 10% increase in FPA enzyme activity compared to the original strain. |
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