Biodegradation Of Poplar And Production Of Triterpenes From The Fermentation Of Sanghuangporus

Lignocellulosic biomass is the most abundant sustainable renewable resource on Earth.Sanghuang is a precious edible and medicinal fungus rich in triterpenoid compounds,and also has a strong ability to degrade lignocellulose.It is of great significance to carry out biodegradation of lignocellulosic biomass,further ferment and degrade it with Sanghuang,and synchronously produce important active products.This study selected the previously screened Peniophora incarnata T-7 strain that can degrade poplar wood and Sanghuang with high lignin degrading ability for synergistic transformation and fermentation experiments of poplar wood,with the aim of producing important fungal active products through biological degradation of poplar wood.The main research results are as follows:1.Studied the pre degradation of poplar wood,and using T-7 for short-term fermentation pretreatment can greatly improve the enzymatic saccharification efficiency of poplar wood.According to the analysis of changes in poplar wood composition,T-7 mainly removes lignin components during the deep fermentation process,with less loss of cellulose components.Enzymatic saccharification analysis showed that after 7 days of treatment with poplar wood,the maximum yields of glucose and xylose reached 33.4%and 27.6%,respectively,both of which increased by 7 times compared to the untreated group.Fourier transform infrared spectroscopy,scanning electron microscopy,XRD,and Py-GC/MS analysis confirmed that the lignocellulosic structure of poplar trees was severely damaged by T-7,and lignin components were preferentially degraded.Proteomic analysis showed that T-7 could secrete a considerable amount of lignocellulases,especially lignin degrading enzymes and hemicellulases,most of which were highly up-regulated on poplar substrates relative to glucose substrates.This study shows that using T-7 for shortterm fermentation pretreatment of poplar wood can greatly improve the enzymatic saccharification efficiency of poplar wood,and has good application potential.2.The compound saccharification of poplar wood by T-7 strain combined with cellulase was studied.It has a significant impact and can be degraded and saccharified by biological methods.On the basis of single factor experiments,it was preliminarily concluded that the appropriate substrate dosage for poplar wood saccharification is 15%,the cellulase amount is 23 IU/g substrate,the T-7 fermentation broth is 1.5 mL/g substrate,the saccharification time is 75 hours,and the saccharification temperature is 45℃.Further optimize the experiment with Box Behnken for four factors and three levels.The quadratic multiple regression equation can be obtained from test analysis and regression fitting analysis as follows:Y=75.65+4.85A+3.42B+5.33C+1.44D+1.38B+1.76C-0.23D-0.080BC+2.75BD1.44CD-23.08A2-14.55B2-17.02C2-17.08D2According to the established quadratic polynomial mathematical model for parameter optimization analysis,the predicted optimal process conditions were as follows:cellulase amount of 23IU/g,T-7 enzyme solution addition amount of 1.5mL,saccharification time of 76h,saccharification temperature of 45℃.Three parallel saccharification experiments were conducted under these conditions,and the actual saccharification rate was measured to be 75.37%.Compared to 57.16%before optimization,the saccharification rate increased by 31.86%.This indicates that the combination of T-7 strain and cellulase has a significant effect on poplar xylation.3.Optimize the process technology for the production of triterpenoid compounds by pre reducing and decoupling of poplar T-7 and Sanghuang(Sanghuangporus lonicericola)fermentation.Establish a quaternion quadratic response surface regression model:Y=289.64+13.94A-9.94B+8.46C+11.16D-1.82AB-0.5175AC-13.01AD-3.42BC5.79BD-5.54CD-43.20A2-12.04B2-34.63C2-28.33D2According to the corresponding values of each factor and the model,the optimal parameters are:corn meal 18 g/L,peptone 4g/L,T-7 degradation time 61 h,poplar wood meal addition amount 26 g/L.Under this condition,the measured triterpene yield can reach 291.21 mg/L,which is 73.93%higher than the 167.43 mg/L before the initial optimization.The results showed that poplar wood can effectively produce triterpenoids through microbial degradation(T-7)and subsequent fermentation and transformation of Sanghuang(S.lonicericola).