Evaluation of enzymes produced from yeast.
Moharib S. A., El-Sayed S. T., Jwanny E. W.
Author Affiliation: National Research Center, Biochemistry Department, Tahrir Street, ET-12622 Dokki, Cairo, Egypt.
Nahrung 44 : 47-51
Abstract : Pichia pinus was capable of growing on mango wastes, producing pectinase (pectin lyase, EC-4.2.2.10) and lactase (?-galactosidase, EC-3.2.1.23) enzymes. The 2 enzymes were successively purified by precipitation with ammonium sulfate followed by chromatography on Sephadex G-120. The purification procedure provided 1846- and 929-fold purification with 20.6 and 24% yield recovery of pectinase and lactase, respectively. The km value of pectinase was 0.33% for pectin at pH 4.5 and that for lactase was 0.166% for lactose at pH 7.0. The purified enzymes are stable up to 50°C for 60 and 45 min, respectively, with 20 and 35% loss of activity. Gel filtration on Sephadex G-200 indicated that the molecular weights of the purified pectinase was 90 × 10³ Da and of lactase was 115 × 10³ Da. The had the potential for treating mango pastes (residues left after mango juice preparation) with the 2 prepared enzymes resulted in an increase of the colour intensity, total carbohydrate content and juice yield. Treating milk with purified lactase also showed an increase in the total carbohydrate and reducing sugar produced.