| Crop Straw is an important biomass resource.China's annual straw yeild is nearly 900 million tons.How to effectively converse and use straw is also the current concern.Microbial methods have become a hot spot in the study of many straw degradation methods with their green safety advantages.And the screening of effective lignocellulose degradation,and high enzyme activity of microorganisms is the key to the development and utilization of straw resources.A fungi of lignocellulose degradation was chosen in this study.Its Genetic information was identified,and its growing situation and enzyme production were analyzed.The corn straw was solid fermented by the utilization of schizophyllum.The changes of the contents and structures of lignocellulose in straw were determined by NREL,and observed by SEM,XRD and FTIR.The degradation products of straw lignocellulose were explored and analyzed by GC / MS.schizophyllum was used to optimize the conditions of the production of cellulase and xylanase with the single factor variables.Based on the different fermentation time,different mash number of straw,different initial pH,different inoculation dosage,and different solid-liquid ratio,the optimum conditions of cellulase and xylanase activity were determined to prepare the crude enzyme.Its thermal stability,lignocellulose content and nutrients were explored,which provides theoretical basis for the subsequent industrial production.The main findings were as follows:(1)The experimental strain was identified as schizophrenia by morphological and molecular biology.(2)Schizophyllum can produce xylanase,cellulase,manganese peroxidase,lignin peroxidase of lignocellulosic enzyme in the solid fermentation process.The highest activity of four enzymes was among 48-96 h fermentation.The activity of cellulase reached the maximum of 28.98U·ml-1 at 64 h,the activity of xylanase reached the maximum of 134.96 U·ml-1 at 96 h,the activity of lignin peroxidase reached the maximum of 452.41U·L-1 at 72 h,the activity of manganese peroxidase reached the maximum of 69.85U·L-1 at 48 h.(3)The structure of the straw was analyzed by SEM,XRD and FTIR(scanning electron microscopy,X-ray diffraction and Fourier transform infrared spectroscopy).The surface plasmodium could destroy the fiber bundles in corn stalks and reduce the crystallinity,so as to degrade cellulose,hemicellulose and lignin.(4)By GC / MS analysis of the degradation products,the products of small molecular aromatic compounds,such as hydrocarbons,palmitic acid and other products appeared in the maize straw products after the degradation by Schizophyllum.(5)The activity of cellulase and xylanase under different conditions was conducted fermentation condition optimization.The results showed that activity of cellulase and xylanase is 85.36 U/mL and 285.99U/mL,increased by74.10% and 50.52% at condition of 14 d,80 mesh of straw,initial pH 5.0,inoculation dosage 4% and solid-liquid ratio 1: 3.5.And a crude enzyme preparation was obtained under the conditon of 49? drying,pulverizing and sieving.activity were relatively high at conditon of the mash number of straw was 80 mesh,the initial pH was 5.0,the inoculation dosage was 4% The solid-liquid ratio was 1: 3.5.The activity of cellulase and xylanase is 85.36 U/mL and 285.99U/mL,increased by74.10% and 50.52% after optimization.And dried under this condition at 49?,pulverized and sieved to obtain a crude enzyme preparation.(6)By analysis of enzyme thermal stability and composition in crude enzyme preparation,the results showed that when the temperature was 50?,the cellulase was inactivated to 50% or less.When the temperature was 70?,the xylanase was inactivated to below 50%.The degradation rate of cellulose,hemicellulose and lignin after optimization was improved by 11.82%,13.57% and 6.55% respectively.Sugar and protein content in the crude enzyme preparation after fermented were 42.8%,12.1%,and increased by 19.4%,6.22%,compared with the original straw. |
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