Purification And Preparation Of Enzyme For The Pectinase By Apocynum Retting Bacteria Producing

Apocynum fiber is a kind of natural wild plant fibers, not only soft, high strength, good moisture absorption but also has a good antimicrobial effect, is a rare textile materials. The enzymatic degumming of apocynum has the characteristics of high fiber production, low environmental pollution and simple process conditions. How to improve stability and efficiency of the degumming enzyme, has the important significance of research for improving the utilization of enzymatic degumming in the industry. This article aims to utilize the technology of carrier-free enzyme immobilization,immobilizing pectinase produced by the apocynum retting bacteria-Bacillus subtilis S-1, in order to improve the efficiency of pectinase retting. The main contents and conclusions of research are as follows:1.Utilizing the technology of cross-linked enzyme aggregates (CLEAs)to immobilize the pectinase produced by Bacillus subtilis S-1, preparing high efficient and stable cross-linked aggregates of pectinase,and conduct a single factor review toward the main factors which affect the preparation of CLEAs for activity, therefore determine the optimum preparation conditions of cross-linking aggregates of pectinase:(1) Aggregating conditions:use80%saturated ammonium sulfate as precipitant, and utilize31.4U/mL solution of pectinase produced by B.subtilis S-1, under the conditions of the solution system at pH9.0and ice water bath, after precipitated for40min, could get a more satisfactory aggregates of pectinase.(2) Cross-linking conditions:use4%(V/V) glutaraldehyde as crosslinker, and the aggregates of pectinase crosslinking135min at30℃, could gain the of performance cross-linking aggregates of pectinase. The activity recovery reach to61.5%.(3) Analysis of enzymatic properties:The optimum temperature of the cross-linking aggregates of pectinase has been upgraded than the free enzyme (40℃), it can reach45℃, the range of optimal temperature was significantly widened; Its optimum pH is10.0, offseted0.5units to the right compared to the free pectinase(pH9.5), and the CLEAs showed good activity at the range on pH9-10.0. The cross-linked aggregates of pectinase has been dramatically improved than free pectinase on thermal stability, pH stability, storage stability, tolerance under organic solvent.2.Found in experiments of apocynum degumming on the use of the cross-linked aggregates of pectinase:utilize5mL,10mg/mL cross-linked aggregates pectinase under the conditions for45℃, pH10.0, after had degummed for8h on the retting liquid of apocynum, the residual rate of gum contented of apocynum skin is approaching4.55%.