Study On Purification And Characterization Of β-Mannanase From CXJZ Strain

The β-mannanase was purified by ultrafiltration, ammonium sulfate precipitate, acetone precipitate and SephadexG-100 gel filtration,and studied on characterization of β-mannanase from CXJZ strain in this paper. So the scientific base was provided for the production and application of β-mannanase. The conclusions was reached as follows in the experiment: the optimum carbon source of CXJZ strain was mannose; but considering the cost, the glucose was defined to carbon source when the fermentation was 7.5h;β-mannanase was purified by 100kD-10kD ultrafiltration, 45%-70% ammonium sulfate precipitate, 1.2:1-1.8:1(V/V) acetone precipitate and SephadexG-100 gel filtration; the yield was 33.50% and the purified folds were 12.05;the single protein band with molecular weight of 52.29kD was gained by SDS-PAGE ;the enzyme was stable in the range of pH 4.6 to 7.0 ; optimum pH was 6.4 ,and the rage of the action pH of the enzyme was from 4.6 to 7.6;the enzyme was stable blow 55℃; action temperature of the enzyme was from35℃to 55℃; optimum temperature was 50℃,and the enzyme was unstable at 70℃; the metal ion Co2+, Hg2+,Mn2+and Ag+ inhibited β-mannanase activity strongly, but Mg2+,Ca2+ and K+ activated the enzyme; kinetics of β-mannanase was examined. The Km values for konjac powder and locust bean gum were 1.57mg/L, 1.75mg/L,and Vmax were 1430μmol/(min? ml), 2500μmol/(min? ml),respectively. It was discovered that –SH, Trp residue and Tyr residue were important for β-mannanase activity.