Beta-galactosidase from a cold-adapted bacterium: purification, characterization and application for lactose hydrolysis.

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Bibtex

@article{7fea5e8f6df040279649ad0149267b7e,
title = "Beta-galactosidase from a cold-adapted bacterium: purification, characterization and application for lactose hydrolysis.",
abstract = "The enzyme beta-galactosidase was purified from a cold-adapted organism isolated from Antarctica. The organism was identified as a psychrotrophic Pseudoalteromonas sp. The enzyme was purified with high yields by a rapid purification scheme involving extraction in an aqueous two-phase system followed by hydrophobic interaction chromatography and ultrafiltration. The beta-galactosidase was optimally active at pH 9 and at 26 degrees C when assayed with o-nitrophenyl-beta-D-galactopyranoside as substrate for 2 min. The enzyme activity was highly sensitive to temperature above 30 degrees C and was undetectable at 40 degrees C. The cations Na+, K+, Mg2+ and Mn2+ activated the enzyme while Ca2+, Hg2+, Cu2+ and Zn2+ inhibited activity. The shelf life of the pure enzyme at 4 degrees C was significantly enhanced in the presence of 0.1% (w/v) polyethyleneimine. The pure beta-galactosidase was also evaluated for lactose hydrolysis. More than 50% lactose hydrolysis was achieved in 8 h in buffer at an enzyme concentration of 1 U/ml, and was increased to 70% in the presence of 0.1% (w/v) polyethyleneimine. The extent of lactose hydrolysis was 40-50% in milk. The enzyme could be immobilized to Sepharose via different chemistries with 60-70% retention of activity. The immobilized enzyme was more stable and its ability to hydrolyze lactose was similar to that of the soluble enzyme.",
author = "S Fernandes and B Geueke and Osvaldo Delgado and J Coleman and Rajni Hatti-Kaul",
year = "2002",
doi = "10.1007/s00253-001-0905-4",
language = "English",
volume = "58",
pages = "313--321",
journal = "Applied Microbiology and Biotechnology",
issn = "1432-0614",
publisher = "Springer",
number = "3",

}