Effective extraction and purification of beta-xylosidase from Trichoderma koningii fermentation culture by aqueous two-phase partitioning

Effective extraction of protein from bulk medium is an important technique in bioresearch. In the present study, we describe an extracellular beta -xy losidase from the fermentation supernatant of Trichoderma koningii G-39 tha t was successfully extracted and purified simultaneously in a single step b y using an aqueous two-phase partitioning method. This two-phase system was prepared by dissolving suitable amount of poly(ethylene glycol) (PEG) and sodium dihydrogenphosphate (NaH2PO4) in aqueous solution. beta -Xylosidase was recovered with high yield and high concentration in the bottom salt-ric h phase when 25% (w/v) PEG 1500 and 20-25% (w/v) NaH2PO4 were applied. Base d on a 1-liter scale extraction, the purity of the enzyme was enhanced at l east 33-fold. The total activity increased 422% in comparison with that in the untreated filtrate. The effectiveness and simplicity may make this tech nique potentially useful in various applications. The transxylosylation act ivity of the enzyme purified by this technique was also investigated. (C) 2 001 Elsevier Science Inc. All rights reserved.