Application Of Low Temperature Plasma And Biological Enzymes For Ramie Degumming

Bio-enzymatic degumming of ramie fiber is a kind of method to decompose gum macromolecules for separating and refining raw ramie fibers.Compared with the traditional chemical degumming,which involves high energy-consumption and serious pollutions,bio-enzymatic degumming shows higher performance,superior quality and free from pollution.Therefore,bio-enzymatic degumming is one of the important development directions in the future.The effects of low temperature plasma(LTP)on the activities of degumming enzymes were investigated in this thesis.Moreover,LTP was also used in the enzymatic degumming of ramie for improving enzymatic activity,as well as the efficiency of bio-enzymatic degumming,in order to meet the requirements of industrial production of ramie fabrics quality.According to the main components of gums on ramie fiber,pectinase,xylanase and ?-mannanase were selected as degummase for ramie fabric in this work to explore the effect of LTP on their activities.At first,the enzyme activity tests were performed,respectively.Then the effects of plasma treatment parameters such as gas pressure,discharge power,exposure time and the experimental gas on the activity of pectinase,xylanase and ?-mannanase,were investigated and optimized by utilizing enzymatic activity as indicator,separately.Finally,the structure changes of enzymes were investigated by FT-IR,fluorescence spectrometry and circular dichroism spectra to disclose the relationship between the enzyme conformational changes and the activity changes.After being treated by their optimized plasma treatment conditions,the enzymes were employed for ramie degumming,as well as the effects of the parameters such as water temperature,pH value,species and ratio of enzymes,and the enzyme dosages on weight loss rate,capillary effect and whitenes.The results show that the activities of pectinase,xylanase and ?-mannanase were improved by low temperature plasma treatment.The optimized plasma treatment conditions for pectinase were oxygen as the experimental gas,gas pressure at 65 Pa,discharge power at 200 W,exposure time for 4min.The optimized plasma treatment conditions for xylanase were argon as the experimental gas,gas pressure at 80 Pa,discharge power at 200 W,exposure time for 4min.The optimized plasma treatment conditions for ?-mannanase were oxygen as the experimental gas,gas pressure at 65 Pa,discharge power at 50 W,exposure time for 2min.By the enzyme after treated by the optimized plasma treatment conditions,a good degumming result was obtained with the weight loss rate at 4.2% in comparison with a lower result about 2.3% fr without plasma treatment.The optimized degumming treatment conditions were temperature at 55?,pH value at 4.0,the utilized ratio in mass of xylanase and pectinase enzymes at 0.57:0.43,the enzyme dosage about 8%(o.m.f).