Research on Purification of β - mannanase by Endophytic Bacillus subtilis

Objective: Isolating and purifing β-mannanase from an endophytic Bacillus subtilis strain UD-20.Method: In the paper,β mannanase was purified using ammonium sulfate salting-out,ethanol precipitation and polyethylene glycol(PEG) / ammonium sulfate [(NH4) 2SO4]aqueous two-phase systems.Result: The recovery rates of the enzyme purified by(NH4) 2SO4 salting-out and ethanol precipitation were 15% and 7.5%,respectively;The purification multiples are 1.968 and 0.977,respectively.Under the optimal systems of PEG2000 22%(m / m),(NH4) 2SO4 16%(m / m),NaCl 2%(m / m),the recovery rate of the enzyme purified by aqueous two-phase systems was 97.16%,the extraction yield was up to 99.26%,and the purification multiple was 2.820.Conclusion: The recovery rates of the enzyme purified by(NH4) 2SO4 salting-out and ethanol precipitation are very low,but the aqueous two-phase systems was very well.