Concentration and purification of beta-glucosidase from Aspergillus niger by using aqueous two-phase partitioning.

The extracellular enzyme beta-glucosidase, present in a culture filtrate and produced by Aspergillus niger, was concentrated up to 700 times by two-phase partitioning. The two-phase systems were achieved by dissolving dextran and poly(ethylene glycol) in the culture filtrate in such proportions that the lower phase, containing the enzyme, consisted of a very small volume compared with the upper phase. The enzyme had high affinity for the lower phase when the system contained 100 mM KSCN at pH 8.0, and the recoveries of beta-glucosidase were in the range of 85 95% with a concentrating factor of 60-720 times. At the same time, the enzyme was purified 2-3 times.