Study On Technology Of Cellulose Materials Comprehensive Utilization

Corn stalks were used as cellulosic materials.The process conditions of acid pretreatment,cellulase solid state culturing,ethanol SSF and chitosan synthesis culturing were investigated.Firstly,dilute sulfuric acid was used as pretreatment reagent.Conditions of pretreatment were studied and determined as showed:concentration of sulfuric acid was 2.0%,solid-liquid ratio was 1:10,pretreatment tempreture was 120℃ and pretreatment time was 2 h.After pretreatment cellulose yield was 93.21%,xylose yield was 87.58%,lignin removal rate was 12.68%and hydrolysis rate of cellulose was 33.87%.Then,Trichoderma reesei Rut C-40 was inoculated to corn stalks after pretreatment for cellulase solid state culturing.The optimum culturing conditions decided through orthogonal test were as followed:5%(NH4)2S04,10%bran,1.0%glucose,and 0.15%tween-80.Substrate was turned for each 24 h.CMCase activity was 287.10 U/g and FPAase activity was 79.64 U/g after 6 days of culturing.Next,cellulase substrate was mixed with con stalks after pretreatment,and Saccharomyces cerevisiae was inoculated to the mixture for ethanol SSF.The best fermentation conditions confirmed by response surface optimization method were as followed:initial pH was 5.0,fermentation tempreture was 36 ℃ and water ratio of substrate was 66%.The ratio of cellulase substrate and corn stalks was 1:1 and inoculation amount was 7×10~7/g.Ethanol yield was 0.125 g/g after 4 days of fermentation.Finally,hdrolysate from pretreatment was detoxificated.The best detoxification process was a neutralization using Ca(OH)2 followed by acticated carbon detoxification.Actinomucor elegans TCCC450005 was inoculated to hydrolysate after detoxification,and the most appropriate culturing conditions were as showed:6%corn steep liquor,initial pH was 7,culturing tempreture was 30℃ and rotational Speed was 200 r/min.Mycelium concentration was 21.12 g/L and chitosan yield was 2.77 g/L after 60 hours of culturing.