The Study Of Kenaf Bast Fiber Degumming By White-rot Fungi

Degumming is a key process during the processing of bast fibers. The existing techniques of degumming include chemical degumming, biological degumming, physical degumming and so on.But the degumming efficiency.the stability of the quality and the serious pollution of the wastewater are the key problems in the industry. Based on the characteristics of high lignin content of kenaf bast fiber and based on the characteristics of complete lignocellulose degrading enzymes system of white-rot fungi, Through the optimization of kenaf bast fiber by white rot fungi degumming process and a preliminary study by degumming Mechanism, This experiment presents a viable production of the new technology. In addition, this experiment also studied the Crafts of enhance laccase production by the co-culture of white-rot fungi.By comparing the growth rate of 10 different test strains on Kenaf fiber, selective medium (Pectin medium, Xylan medium, Kenaf lignin medium and CMC-Na medium), Using the preliminary screening method by rapid screening of ABTS-plate and Mn-plate to ensure that Co.v is a superior white-rot fungi in kenaf degumming.Optimization of the process of Kenaf bast fiber degumming by Co.v strains. This expriment using the method of liquid inoculation and solid fermentation. We evaluated the quality of degummed fibers by residual gum content, feel, color, softness and fiber strength. This experiment is optimized degumming time, degumming temperature and inoculation amount. The results showed that the optimum conditions for Kenaf bast fiber degumming is unglued 4 d at the conditions of 29℃,1.5 mL/g, Kenaf bast fiber residual gum content only remaining 10.2%.By observing change of fiber strength, Chemical composition of the fibers, Several degumming enzymatic activity, combined with microscopic observation of the fibrous tissue and the FTIR analysis in the process of degumming. The results showed that, Co.v degradation of kenaf bast fiber is selective. In the initial stages of degumming (0-4 d), Co.v preferentially degrades the lignin of bast fiber, the enzyme activity of laccase and manganese peroxidase, which is involved in lignin degradation, was rapidly increased. The xylanase and endoglucanase activity increased slowly, the degradation of cellulose and hemicellulose is relatively slow. Due to the removal of the Non-cellulose components in the fiber structure, the stress of the various parts is more uniform, and the fiber bundle breaking strength reaches the maximum at the time of 4 d. Unglued after 4 d, lignin degradation began slowing down, Xylanase enzyme and endoglucanase activity began to jump up, the degradation of cellulose and hemicellulose accelerated, the fiber structure gradually destroyed and the fiber strength gradually decreased.To improve the production of Laccase by combining White-Rot Fungal strains,screening out the best combination of white rot fungi and using response surface method to optimize the fermentation medium.By single factor and response surface test results to determine the best medium for Laccase production paint formula is:The amount of wheat bran 11.81g/L, NH4NO3 1.22g/L, Pyrogallic Acid 0.72mmol/L, Cu2+ 0.28mmol/L. The optimized medium laccase activity reached 13.87U/mL, is 5.97 times before optimization, is 34.34 times the single strain culture.To achieve a substantial improvement of the strain laccase production. The study laid a good material foundation for the enzyme method in the future.