Fractionation Of The Three Main Components From P.Sinese And Using For High Value Products

P.sinese is a perennial herb that planting in North and South China in large-scale cultivation for the easy planting property and high production yield(300-500 tons/HA).The cellulose and hemicellulose account for more than 70%in this material,as well as 16%of lignin.Therefore,P.sinese was recognized as one of the lignocellulosic material with promising application.Up to now,P.sinese was only used for edible fungus cultivation,feed production,etc.Therefore,there is still an urgent need to explore the potential high value products.In this thesis,the fractionation method of cellulose,hemicellulose and lignin from P.sinese was carried out,the technology and theory of lactic acid and xylitol production from cellulose and hemicellulose was investigated,the method of lignin sulfonate with high sulfonated degree from separated lignin was performed.All these conclusions laid the technical and theoretical basis for value-added utilization of P.sinese.The main content of this thesis was listed as below:(1)The cellulose,hemicellulose and lignin could be fractionated by environmental friendly microwave-assisted H2O2-NaOH extraction coupled with acidic and ethanol precipitation.The crude yield of cellulose,hemicellulose and lignin was 42.79%,21.87%and 15.18%,respectively,under the condition of solid to liquid ratio of 1:25,hydrogen peroxide concentration of 0.5%,sodium hydroxide concentration of 4%,temperature of 75 ? and time of 4 hour.Many modern analysis methods was employed for the analysis of treated material,such as SEM,XRD,IR,13C-NMR,'H-NMR,etc.Results showed that the microwave effect can destroy the crystalline area of the cellulose and make the removal of the amorphous areas of cellulose,the Cry? of raw material and separated cellulose was 73.18%and 78.98%,respectively.The separated cellulose has classical structure of cellulose and constructed by long chain molecular of glucose.Hemicellulose was polysaccharide,consisted by xylose as main chain and arabinose as branched chain.Lignin was classic structure of herbicides,mainly consisted of G-S style of lignin with a small amount of H-lignin.(2)The cellulose fractionated from P.sinese was hydrolyzed by enzyme at first,and then fermented by lactobacillus LQL37 strain to produce lactic acid.The glucose yield of 98.2%was obtained after enzymatic hydrolysis under condition of substrate concentration of 5%,enzyme dosage of 20 FPIU·g-1 cellulose,temperature of 50 ?,time of 36 h and pH of 4.8.The optimized fermentation condition was glucose initial concentration of 150 mg·mL-1,inoculum concentration of 5%,temperature of 46 ?,time of 60 h,initial pH of 6.5 and total CaCO3 dosage of 6%,which was used firstly to adjust pH to 6.5,and then the residual of CaCO3 was added into the system in every 12 h for five times equally.The sugar conversion was higher than 92.5%and L-lactic acid accounted for more than 97%of the total acid in the fermented liquid under above condition.(3)The hemicellulose fractionated from P.sinese was hydrolyzed by dilute sulfuric acid at first,and then fermented by tropical candida JS-3-123-39 strain to produce xylitol.The xylose yield of 86.5%can be achieved under condition of sulfuric acid concentration of 1%,temperature of 105 ?,time of 4 hours and solid to liquor of 1:20.The hemicellulose hydrolysate was detoxificated by using lime milk neutralization and vacuum concentration to remove acetic acid,furfural,etc.On the other hand,active carbon can be used for decoloring under condition of dosage of 1.5%,speed of 200 r-min-1,temperature of 50 ?,and 20 minutes in thermostat oscillator.The optimal fermentation condition for xylose was strain culture time of 22 hours,initial xylose concentration of 120 mg-L-1,initial pH of 5.5,inoculum concentration of 10%,fermentation temperature of 32 ?,time of 72 hours,nitrogen source addition of 5 mL,dissolved oxygen conditions was set by six layers of gauze to cover the bottle mouse,liquid load was 75/250 mL.The speed for shaking bath was 210 r·min-1 for the first 0-24 hours,and then changed to 180 r·min-1 for the rest of time.(4)The lignin sulfonate with high sulfonated degree was produce by H2O2 oxidation,formaldehyde hydroxyl methylation and NaHSO3 sulfonation.The optimal condition was initial pH of 10.5,H2O2 dosage of 3%,oxidation temperature of 40-60 ?,time of 40 min,formalde dosage of 4%,hydroxyl methylation temperature of 40 min,NaHSO3 dosage of 18%,sulfonation temperature of 105 ?,time 3.5 h.In Comparison with the Grade A commercial sodium lignosulphonate,our product met or exceed in many parameters except for the a little bit higher sulfate content.(5)The thermal stability was carried out for cellulose,hemicellulose and lignin separated from P.sinese.Results showed that the difference of molecular and structure lead to the varied thermal behavior.The weight loss of 75%happened at 240-500 ? for cellulose,while the mainly thermal degradation for hemicellulose was 200-400 ?,which accounting for 78%.On the other hand,the thermal degradation for lignin was relatively broad(200-700 ?),which lead to 79.2%of weight loss.