Screening Of Strains Degumming The Bast Of Broussonetia Papyrifera

Broussonetia papyrifera, also called muramidase, fast-growing hardwood species,deciduous arbors, moraceae family, broussonetia papyrifera vent group, was selected asspecial tree species to make paper pulp.In this paper, strains for degumming and casting off exodermis (black and green) ofbroussonetia papyrifera was screened, and growing conditions of superior strains screenedwere optimized, and bio-pulping process conditions were explored, and reseach on effect ofmechanical pre-treatment on shortening bio-pulping cycle was conducted, and enzymeactivity of degumming enzyme were determined, and ion induced mutation of superiorstrains was explored.Five high-producing complex phosphoesterasum strains were isolated from the waterof flax retting broussonetia papyrifera through first and second screen. Its optimal growthcondition was pH6.5and30℃.It was found that the optimum conditions of bio-pulping were: initial pH7,35℃,liquor ratio(material∶water＝W∶V)1∶20, the amount of inoculation4%; urea0.1%,maiz extract2%and K2HPO40.1%were added after retting. The pulping period was68h.The analysis of enzyme activity for bast bio-pulping of Broussonetia papyrifera shewthat the activities of enzymes all increased with the time increase in initial fermentationstage,the pectinase activity reached maximum60.03U/mL at36h, and can be up to; thehemicellulase activity reached maximum37.79U/mL at48h; pectinase activity andhemicellulase activity gradually decreased afterward. The cellulase activity increasedslowly in the whole period.The period of bio-pulping after mechanical pretreatment was only34h, and could beshortened by50%, which is close to the period of direct bio-pulping. The pectinase activityin these two process were very close, and was60.05U/mL,60.03U/mL respectively. Thepeak of pectinase activity was at the time of36h.The induced mutation by plasma on superior strains at0.05MPa for3min couldimprove the pectinase activity to65.84U/mL increased by9.68%, and the pulping period could be shortened2h.Strains was identified as the genus bacillus on the basis of16S rDNA identification.