Purification and Characterization of β-Mannanase from Bacillus stearothermophilus Strain 2004

The optimal shaking condition for the enzyme production,purification and enzymology of β-mannanase by Bacillus stearothermophilus Strain 2004 was investigated.β-mannanase maximum activity of 41.92 U/mL was recorded under the optimal condition of 1.5 %,2% peptone and 40 ℃ with the medium working volume of 70 mL in 250 mL flask.The β-mannanase was isolated and purified by using(NH_(4))_(2)SO_(4) precipitation,Sephadex G-200 column gel filtration and DEAE-Cellulose DE52 ion-exchange chromatography.The purified enzyme showed a specific activity of 722 U/mg with the purity of 23.94 times over the crude enzyme and the yield of 35.1%.The purified enzyme performed the maximum activity at the range of 70 ℃ to 80 ℃and pH of 5.8~6.2.The enzyme was stable over the range of pH 4.0~9.0.The activity of enzyme was further enhanced by and K~(+) and Mg~(2+).Under a certain concentration,Mg~(2+) had a significant activation on the purified enzyme and protection from thermo-denaturation.