Study On The Reaction Course Of The Bio-pulping Of Mulberry Bast

Bast fiber as raw material for bio-pulping has become a hot topic for its environmental-friendly and high quality fiber for paper in pulp and papermaking industry. In this paper, thereaction of the mulberry bark enzyme pulping has been researched. First, through theexperimental conditions to find out the optimal enzymes concentration and dosage, systemtemperature and pH value, it is considered pentosan content, pectin content and lignincontent as the main factors. Then, follow a different time of the content of each component,and analysis the reaction of the enzymatic treatment of mulberry bark. At last, through theIR and NMR to comparison and analysis the change of the structure in pectin and lignin.In the paper, it is taken the pectinase as the activity enzyme, then determine of theoptimum conditions for biological pulping by experimental conditions. Using of singlefactor experiments and orthogonal experiment and the method to determine the optimalconditions for bio-pulping and in experimental cases, the experimental results of each factorof influence. The results show that when the temperature is50℃, system pH value is4,and enzyme concentration is1.0‰, the treatment can achieve the desired effect. In thiscondition, pentosan content decreased from10.05%to7.83%, down2.22%; pectin contentdecreased from8.86%to3.13%and its removal rate reach to64.67%; Kappa number fromthe initial29.51dropped to19.23, down11.28. Conditions in the laboratory within thescope of the selected external factors, the temperature of the three levels caused the largestdifference of pectin removal, that is, temperature is the largest factor, followed is pH value,and the amount of enzyme is the least.Then the reaction process of the enzymatic removal of pectin on the bark is studied, atthe different time of the process, the determination of pentosan and pectin content, as wellas Kappa number is measured. It can be shown that at the first30min, pectin removal rate issmall, at a range from8.86%to7.75%, down only1.11%, while in the stage of30min~120min, a large number of pectin is removed, pectin content in the decreased from7.75%to3.66%, remove the69.91%of all the removal pectin, and in the120~300min, the pectin content decreased by only0.64%. Similarly, Kappa number also decreased largely。 Butpentosan content decreased by only2.22%.Before and after enzymatic treatment from the fiber morphology, structure of pectinand lignin infrared IR and NMR structure analysis shows that removal of most of the pectinenzyme treatment, but there are still a small part of the residual, which pectinase may be asingle selective; in the enzyme before and after treatment, changes in the structure of pectinoccurred; on the structure of lignin analysis, the raw materials in the lignin and residuallignin structure is changed, indicating that the process of enzyme treatment of woodreduction factors may have hydroxy ether synthesis reaction, and may be the oxidation oflignin to produce a new conjugated carbonyl.