Physicochemical and bilogical characterization of soils from the vicinity of the Arctowski Polish Antarctic Station

Soil samples collected in 2006 from 4 different sites (Puchalski Hill and a moraine below this hill, an elephant seal colony and a penguin rookery) in the vicinity of Arctowski Polish Antarctic Station at King George Island were characterized in terms of physicochemical properties (pH, humidity, concentration of selected inorganic and organic substances), microbial colonization and the overall activity of selected enzymes (differentglycosidases and esterases). Activity of the latter enzymes was assayed by p-nitrophenyl and 4-methylumbelliferone derivatives of fatty acids (by spectrophotometric and fluorimetric method, respectively). The highest lipolytic activity was found in soils from the elephant seal colony and penguin rookery

Psychrophilic microorganisms and their biotechnological potential

Research concerning extremophilic microorganisms have appreciably extended our knowledge about the life limits. Psychrophiles, which are coldadapted microorganisms (some thrive even at -20°C) rank the first in abundance to the other groups of extremophiles. They populate the harshest environments on Earth, like permafrost, marine and glaciers ice, the highest parts of mountains, clouds and stratosphere. Psychrophiles have developed numerous molecular adaptations, without which they would not be able to persist in cold biotops. They produce protective exopolymers and low molecular weight cryoprotectants, polyunsaturated and branched fatty acids, which provide the appropriate fluidity of cell membranes — essential for the communication with the environment, and different sorts of proteins, like ice nucleating proteins, cold shock and cold acclimation proteins and enzymes, characterized by molecular and kinetic adaptations to catalysis of metabolic reactions at low temperatures. All these biomolecules are extremely interesting for biotechnologists because they can either widen the assortment of products applicable to industry and medicine or be valuable molecular tools to be used in biotechnology for the manufacture of these products. The properties of psychrophilic microorganisms imply that development of life is possible also in some extraterrestrial environments

Thermostable Pyrococcus woesei β-D-galactosidase - high level expression, purification and biochemical properties

The gene encoding β-D-galactosidase from Pyrococcus woesei was PCR amplified, cloned, expressed in Escherichia coli under the control of an inducible T7 promoter, purified and characterized. The expression system was developed by the construction of recombinant plasmid, based on the high copy number pUET1 vector, giving four times more efficient expression of P. woesei β-D-galactosidase (20 mg of enzyme from 1 liter of culture) than that obtained from a previously constructed one. The recombinant enzymes were purified in a two-step procedure: double heat-denaturation of E. coli cell proteins and affinity chromatography on p-aminobenzyl 1-thio-β-D-galactopyranoside-agarose. To achieve efficient purification of P. woesei β-D-galactosidase by immobilized metal-ion affinity chromatography (IMAC), a His-tag was placed either at the N- or the C-terminal of the coding sequence. The obtained fusion proteins revealed the same specific activity of approximately 5400 U/mg, which was 10 times lower than the wild-type β-D-galactosidase (51100 U/mg). The activity of P. woesei β-D-galactosidase was enhanced by thiol compounds, Mg2+ ions and D-galactose, and was inhibited by heavy metal ions and D-glucose, while Ca2+ ions had no effect

Extremophilic and modified aminotransferases as a versatile tool for the synthesis of optically pure building blocks for pharmaceutical industry

Considerable progress has been made in the past few years with industrial use of essential key intermediates for chemical and pharmaceutical industry. The increasing demand for obtaining chiral drugs in enantiomerically pure form makes it necessary to search for novel biocatalysts useful in the synthesis of amino acids, chiral amines, amino sugars and alcohols. According to the reaction mechanism, aminotransferases (ATs) have useful applications because of their capability of transfer of an amino group from a donor substrate to an acceptor, thus resulting in the synthesis of a wide variety of building blocks. This article reviews current biocatalytic approaches using microbial ATs in the synthesis of optically active products. Focus is also put on the engineering of ATs and their limitations in the industrial applications. Moreover this review covers biocatalytic approaches using ATs isolated from extreme environments

Identification of the csp gene and molecular modelling of the CspA-like protein from Antarctic soil-dwelling psychrotrophic bacterium Psychrobacter sp. B6

We cloned and sequenced the cspA-like gene from a psychrotrophic Antarctic soil-dwelling bacterial strain Psychrobacter sp. B6. The gene is 213 bp long and shows 99% and 98% sequence identity with the Psychrobacter cryohalolentis K5 gene encoding a cold-shock DNA-binding domain protein and the Psychrobacter arcticus transcriptional regulator-CspA gene, respectively. The protein encoded by the Psychrobacter sp. B6 cspA-like gene shows 100% identity with the two proteins mentioned above, and also 61% sequence identity with CspB from Bacillus subtilis and Csp from Bacillus caldolyticus, and 56% - with Escherichia coli CspA protein. A three-dimensional model of the CspA-like protein from Psychrobacter sp. B6 was generated based on three known structures of cold shock proteins: the crystal structure of the major cold shock protein from Escherichia coli (CspA), the NMR structure of the latter protein, and the NMR structure of Csp from Thermotoga maritima. The deduced structure of the CspA-like protein from Psychrobacter sp. B6 was found to be very similar to these known structures of Csp-like proteins