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The gram-negative antarctic bacterium Pseudoalteromonas sp. 22b, isolated from the alimentary tract of krill Thyssanoessa macrura, synthesizes an intracellular cold-adapted beta-galactosidase. The gene encoding this beta-galactosidase has been PCR amplified, cloned, expressed in Escherichia coli, purified, and characterized. The enzyme is active as a(More)
BACKGROUND β-D-Galactosidases (EC 3.2.1.23) catalyze the hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides. Cold-active β-D-galactosidases have recently become a focus of attention of researchers and dairy product manufactures owing to theirs ability to: (i) eliminate of lactose from refrigerated milk for people afflicted with(More)
A psychrotrophic bacterium producing a cold-adapted esterase upon growth at low temperatures was isolated from the alimentary tract of Antarctic krill Euphasia superba Dana, and classified as Pseudoalteromonas sp. strain 643A. A genomic DNA library of strain 643A was introduced into Escherichia coli TOP10F', and screening on tributyrin-containing agar(More)
We report the identification and nucleotide sequence analysis of pKW1, a plasmid of the psychrotrophic bacterium Pseudoalteromonas sp. 643A isolated from the stomach of Antarctic krill Euphasia superba. pKW1 consists of 4583 bp, has a G+C content of 43% and seven putative open reading frames (ORFs). The deduced amino acid sequence from ORF-1 shared(More)
In this work, we present the construction of a metagenomic library in Escherichia coli using pUC19 vector and environmental DNA directly isolated from Antarctic topsoil and screened for lipolytic enzymes. Screening on agar supplemented with olive oil and rhodamine B revealed one clone with lipolytic activity (Lip1) out of 1000 E. coli clones. This clone(More)
BACKGROUND Cold-active enzymes, sourced from cold-adapted organisms, are characterized by high catalytic efficiencies at low temperatures compared with their mesophilic counterparts, which have poor activity. This property makes them advantageous for biotechnology applications as it: (i) saves energy costs, (ii) shortens the times for processes operated at(More)
A cryptic plasmid pSFKW33 from psychrotrophic bacterium Shewanella sp. 33B, an isolate from the Gulf of Gdansk (the Baltic Sea), was sequenced and characterized. It is an 8021bp circular molecule with 38% GC content, which shows a distinctive nucleotide sequence without homology to other known plasmids. The nucleotide sequence analysis predicts eight open(More)
The crystal structure of the esterase EstA from the cold-adapted bacterium Pseudoalteromonas sp. 643A was determined in a covalently inhibited form at a resolution of 1.35 A. The enzyme has a typical SGNH hydrolase structure consisting of a single domain containing a five-stranded beta-sheet, with three helices at the convex side and two helices at the(More)
The marine, psychrotolerant, rod-shaped and Gram-negative bacterium 22b (the best of 41 beta-galactosidase producers out of 107 Antarctic strains subjected to screening), classified as Pseudoalteromonas sp. based on 16S rRNA gene sequence, isolated from the alimentary tract of Antarctic krill Thyssanoessa macrura, synthesizes an intracellular cold-adapted(More)
A psychrotrophic bacterium producing a cold-adapted beta-galactosidase upon growth at low temperatures was classified as Arthrobacter sp. 20B. A genomic DNA library of strain 20B introduced into Escherichia coli TOP10F' and screening on X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside)-containing agar plates led to the isolation of(More)