Screening Of China-hemp's Lignin Degradation Microorganisms And Optimization Of Culture Conditions

As a kind of special biological resource that hasdeveloped rapidly in recent years,hemp can be widely used in the fields of textile,papermaking,food,medicine,construction,transportation,anddefense military.In the paper industry,due to the high content of ?-cellulose,it has attracted the attention of the papermaking industry in many countries.In the traditional paper industry,waste water and wastedischarge seriously pollute the environment.Therefore,biological pulping is being researched and applied more and more widely.Biopulping is mainly based on microbialdecomposition.Combined with various physical cracking and mechanical cracking cross compounding process,it can achieve zero emissions,no pollution,no industrial waste gas,no suspended matter,save energy,save raw materials,reduce production costs.Through the review of a large number ofdocuments,this study planed todetermine strains that were suitable for biological pretreatment of papermaking raw materials by optimizing the ability of microbial degradation of lignin and cellulose,collecting soil samples and fungal fruiting bodies,and optimizing the enzyme production conditions.In order to achieve the purpose of biopulping pretreatment using hemp.Fifty-one strains of fungi were obtained from the collected soil samples and fruiting body samples.Two fungi were obtained after enzyme activitydetermination and guaiacol plate screening.The strains were initially identified as Trametes hirsute(Wulfen)Pilát and Fomes fomentarius(L.:Fr.)Kick..Afterdetermining the growth rate and comparison of enzyme activities,it wasdetermined that the tested strain was Trametes hirsute(Wulfen)Pilát.In order to further improve the activity of lignin peroxidase produced by Trametes hirsute(Wulfen)Pilát,the fermentation conditions and the addition of exogenous inducers were optimized.For the optimization of fermentation conditions,five factors were selected in this study.Single factor experiment was conducted and four significant factors were selected,namely fermentation time,fermentation temperature,liquid loading amount,and microbe inoculation amount,and a central composite experimental design(BBD)was conducted.After optimization,the fermentation time was 6.75 d,fermentation temperature was 30 ?,liquid volume was 64 ml,the amount of 12 inoculated optimum conditions for enzyme production,lignin peroxidase activity was measured 689.938 U/L.The activity of lignin peroxidase before and after optimization was optimized.The optimum lignin activity was 503.29 U/L for fermentation of hemp straw before fermentation.The enzyme production activity was 720.09 U/L after fermentation conditions were optimized,the lignin peroxidase activity after optimization was increased 43.08 %.The exogenous inducer was added to increase the enzyme-producing activity of Trametes hirsute(Wulfen)Pilát.In this paper,different concentrations of veratryl alcohol solution,benzyl alcohol solution,Tween 80 solution and methyl jasmonate were added to the culture medium.The results showed that the effect of adding veratryl alcohol on improving enzyme activity was greatest in th e four exogenous inducers.Based on this,orthogonal testdesign was performed.After optimization,the result was:80 ?L of 40 m M veratryl alcohol 70 ?L of 10 ml/L benzyl alcohol 10 ml/L of Tween 80 and 1.6 ?L of Me JA were added to 100 ?L enzyme-producing medium.Three groups of parallel experiments were performed and the lignin peroxidase activity was measured by the veratrol method.The average value of the enzyme activity was 650.2049 U/L,which was 45.07 % higher than that before optimization.