Soy Meal Waste Extract as Cultivation Medium for Production of Extracellular ???±-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 ???±-galactosidase in submerged fermentation of the filamentous fungus Humicola lutea 120?￠????5. Maximum enzyme activity (2000 U.l ?￠????1 ) was produced when the soy meal extract containing 5% dry substances (?￠????1% raffinose oligosaccharides) was used at 120th h cultivation and 35???°C. Chromatography on Sephadex G-100 and DEAE-cellulose resulted in a purified ???±-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???°C. The partially purified enzyme was stable up to 40???°C at pH 2.0 to 7.5. The crude enzyme preparation readily hydrolyzes raffinose 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 producing ???±-galactosidase for food and fodder purposes.