SOY MEAL WASTE EXTRACT AS CULTIVATION MEDIUM FOR PRODUCTION OF EXTRACELLULAR alpha-GALACTOSIDASE FROM THE FUNGUS HUMICOLA LUTEA 120-5

摘要

Soy meal extract presenting a waste product from soy protein concentrate manufacture was applied as cultivation medium for the production of extracellular alpha-galactosidase in submerged fermentation of the filamentous fungus Humicola lutea 120-5. Maximum enzyme activity (2000 U.I~(-1)) was produced when the soy meal extract containing 5% dry substances (-1% rqffinose oligosaccharides) was used at 120th h cultivation and 35 deg C. Chromatography on Sephadex G-100 and DEAE-cellulose resulted in a purified a-galactosidase fraction with specific enzyme activity of 37 U.mg~(-1). The optimum conditions for the enzyme reaction were pH 4.0 to 4.5 at 50 deg C. The partially purified enzyme was stable up to 40 deg C atpH2.0 to 7.5. The crude enzyme preparation readily hydrolyzes rqffinose according HPLC analysis, but no activity against disaccharides as sucrose and melibiose was observed. The soy meal waste extract can be recommended as a suitable medium for the industrial cultivation of strains producinga-galactosidase for food and fodder purposes.