The Research On Effect And Mechanism Of Compound Enzyme From Saccharomonospora Viridis Bleaching Pulps

In this study, the effect and mechanism of compound enzyme from Saccharomonospora viridis bleaching pulps was researched. Works mainly included that exploring the best ferment conditions and the rule of producing enzymes, characterizing the enzymology characteristic of compound enzyme, fishing out the best technics of compound enzyme bleaching pulps, assessing the effect of compound enzyme bleaching pulps, discussing the advantages and potentials of compound enzyme bleaching pulps and explaining the process and mechanism of compound enzyme affecting the hemicellulose, lignin, LCC and cellulose in pulps.The results of exploring the best ferment conditions and the rule of producing enzymes showed that deal powder + cotton yarn compoud substrate was the optimal enzyme-induction medium, there was little cellulase in the compound enzyme, the courses of producing xylanase and albumen were almost consistent. 156h was the optimal sampling time.The results of characterizing the enzymology characteristic of compound enzyme showed that Saccharomonospora viridis might be taken as a gene bank for screening alkali-tolerant thermostable xylanase and lignin peroxidase which produced both xylanase and lignin peroxidase at the same time and the compound enzyme was maximally active at pH 7 and retained 63.55 % activity at 90℃for 3h, the molecular weight of xylanase in compound enzyme was about 31 KD.The results of fishing out the best technics of compound enzyme bleaching pulps and assessing the effect of compound enzyme bleaching pulps showed that the best technics of compound enzyme bleaching pulps were enzyme dosage 30U/g (calculated by xylanase), pH 7, temperature 80℃, time 120min, pulp consistency 10%, H2O2 0.1mmol/L, enzymatic treatment with the compound enzyme had beneficial effects on bleachability of pulp and the direct brightening, removal of xylan, lignin and LCC were already observed on the stage of enzymatic treatment and led to increase in ISO brightness and decrease in pentosan, lignin and LCC contents, the brightness improvement under equal or reduced consumption of active bleaching chemicals was all noted after the subsequent bleaching.The results of discussing the advantages and potentials of compound enzyme bleaching pulps showed that the effects of compound enzyme bleaching pulps were prior to all the pure commercial enzymes and almost equivalent to the manual mixing enzymes, because of its thermostability and alkali-tolerance, compound enzyme bleaching pulps could reduce the consumption of energy in pulp bleaching process.The results of explaining the process and mechanism of compound enzyme affecting the hemicellulose, lignin, LCC and cellulose in pulps showed that compoud enzyme treatment degraded xylans and poly-arabinose evidently, it dissolved small molecular lignin and LCC, reduced chromophores and auxochromes in pulp, enzymatic treatment also loosened fibre structure, thus strengthened the infiltration of chemicals in subsequent bleaching and promoted the dissolution of remnant lignin, crystallinity of enzymatic treatment pulp was enhanced.This study is concerned with an interdiscipline research subject. The results are benificial to environment protection and have potential prospect of application.