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Production and characterization of b-galactosidase from psychrotrophic Bacillus subtilis

$ beta$-Galactosidase (E.C. 3.2.1.23) or lactase was produced by the growth of a selected Bacillus subtilis strain (KL88) which was adapted to grow at 10$ sp circ$C. The growth and enzyme production were maximal at 2% (w/v) lactose supplemented with 0.2% (w/v) yeast extract. A Fast Protein Liquid Chromatography system (FPLC) was used for $ beta$-galactosidase purification. The enzyme was purified to 44-fold over the crude extract with a recovery of $ sim$54%. Native-PAGE and SDS-PAGE using "PhastSystem" showed the presence of two isoenzymes having molecular weights of 88 and 170 kD. The purified enzyme showed high activity at low temperatures (10$ sp circ$C) and recorded an optimum pH of 7.0. The K$ sb{ rm m}$ values were found to be 2.21 mM and 28.08 mM for o-nitrophenyl-$ beta$-D-galactopyranoside (ONPG) and lactose, respectively. / $ beta$-Galactosidase from psychrotrophic Bacillus subtilis was specific to the $ beta$-D-glycosidic linkage normally present in lactose. / To investigate the possibility of producing proteinase-free $ beta$-galactosidase from this psychrotrophic microorganism, FPLC was used for the rapid separation of $ beta$-galactosidase.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.59294
Date January 1989
CreatorsAbdelrahim, Khalid Ali
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (Department of Food Science and Agricultural Chemistry.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001070030, proquestno: AAIMM63505, Theses scanned by UMI/ProQuest.

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