Aqueous two-phase extraction coupled with ultrafiltration for purificationof amyloglucosidase

Aqueous two phase extraction (ATPE) in combination with ultrafiltration was employed for concentration and purification of amyloglucosidase produced b y solid state fermentation. After extraction (with water) from dry moldy br an the dilute enzyme extract was concentrated by ATPE in a polyethylene gly col (PEG)/maltodextrin (MDX) system. The enzyme in the top PEG rich phase w as then extracted into a Na2HPO4 rich bottom phase and further concentrated by ultrafiltration. The partitioning behavior of amyloglucosidase was exam ined in PEG/MDX, PEG/Na2SO4, PEG/Na2HPO4, PEG/KH2PO4 aqueous two phase syst ems. Effect of buffering salts such as NaCl, Na2HPO4, KH2PO4 and Na2SO4 on the partitioning behavior of enzyme was studied in PEG/MDX system, Maximum partitioning of amyloglucosidase was seen with KH7PO4 (m = 18.1). A two sta ge ATPE employing PEG/MDX (buffered with RH2PO4) and PEG/Na2HPO4 systems, f ollowed by ultrafiltration has resulted in an overall recovery of 78.4% wit h 3.1 fold purification and 9.4 fold concentration of the enzyme.