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Beta-galactosidase activity of proteins extracted from Sulfolobus shibatae

100%

Wolosowska S. , Synowiecki J.

Biotechnologia

2003

nr 2

268-279

The cytoplasmic -beta galactosidase/beta-glucosidase from hyperthermophilic archaeon Sulfolobus shibatae has been characterized with regard to its use in lactose hydrolysis. Cell extract was purified 16-fold to a specific activity 29.5 U/mg using ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. Isolated enzyme exhibited optimum activity at pH 5.5 and 98C and had a half-life of 7 h in acetate buffer (pH 5.5) at 90C. Cu2+, Hg2+ and Zn2+ strongly inhibited the enzyme, whereas catalytic properties of other investigated cations were barely influenced. Glucose and galactose were predominantly produced from lactose. However, at the substrate concentration of 0.15, M small amount of lactose was converted into transgalactosylation products.

Immobilization of recombinant beta-galactosidase in reactions catalysed by transglutaminase

100%

Wolosowska S. , Synowiecki J.

Biotechnologia

2005

nr 3

209-220

Thermostable beta-galactosidase from Escherichia coli transformant containing the enzyme gene from Pyrococcus woesei was immobilized at pH 5.5 on silica gel by crosslinking with transglutaminase. The obtained preparations had a specific activity of 11.573 U/g of support at 70C using oNPG as a substrate. The optimum pH and temperature for immobilized beta-galactosidase activity were 5.5 and 95C. The immobilized enzyme is stable at the temperatures close to the optimal value and the residual activity for oNPG hydrolysis of the preparations incubated 1 h in 0.1 M phosphate citrate buffer (pH 5.5) at 100C was about 70% of the initial value.

Influence of reaction conditions on yield of enzymatic synthesis galactooligosacharides by Penicillium canescens beta-galactosidase

100%

Bednarski W. , Kulikowska A.

Biotechnologia

2007

nr 2

137-148

The aim of the work was to examine the ability of Penicillium canescens beta-galactosidase to synthesize galactooligosacharides in one or two-phase medium (organic solvents: water). The yield of this process depends mainly on: lactose concentration in water phase, time of reaction, kind of organic solvents and their participation in two-phase medium. The application of ultrafiltration for separation of saccharides from the reaction medium stabilized the yield of galactooligosacharides synthesis.

Suitability and properties of beta-galactosidases from different sources

100%

Synowiecki J. , Maciunska J.

Biotechnologia

2000

nr 1

117-123

The article reviews the progress of investigations of b-galactosidases from microbial sources. These enzymes show great differences in optimal conditions of lactose hydrolysis and their utilisation create new possibilities to improve milk and milk by-products processing. Some beta-galactosidases from extreme thermophiles have significant activity above 100?C. Possible applications and interrelationship of both molecular structure and thermostability of these enzymes are also discussed.

Trials of stimulation extracellular secretion of beta-galactosidase synthesised by Kluyveromyces fragilis 28

100%

Demczuk A. , Kowalewska-Piontas J. , Bednarski W.

Biotechnologia

2004

nr 1

253-259

To induce extracellular secretion of beta-galactosidase synthesised by Kluyveromyces fragilis 28 yeasts, we used: glycin, L-asparagine, L-leucine, dimethylformamide, dimethyl sulfoxide, cetyldimethylethylammonium bromide, penicillin G and glycolipids from Candida antarctica. The highest increase in the secretion of beta-galactosidase was obtained in the yeast culture cultivated in the medium with polypeptone when glycin was used as the secretion inductor. The extracellular activity of beta-galactosidase reached 0.416 A.U./ml, and was 10-fold higher than the beta-galactosidase activity reported in the control group.

Improvement of beta-galactosidase properties and conditions for its microbial biosynthesis

88%

Bednarski W. , Kowalewska-Piontas J.

Biotechnologia

2000

nr 2

131-141

We present examples of genetic modification of microorganisms capable of beta-galactosidase synthesis. The technological characteristics as termostability, high activity in a low temperature is improved. We also describe intensification of beta-galactosidase secretion to the medium.