The effect of physico-chemical parameters and chemical compounds on the activity of beta-d-galactosidase (B-GAL), a marker enzyme for indicator microorganisms in water.
The presence of coliforms in polluted water was determined enzymatically (in situ) by directly monitoring the activity of beta-d-galactosidase (B-GAL) through the hydrolysis of the yellow chromogenic subtrate, chlorophenol red beta-d-galactopyranoside (CPRG), which produced a red chlorophenol red (CPR) product. The objectives of this study were to monitor the effect of compounds commonly found in the environment and used in water treatment on a B-GAL CPRG assay and to investigate the differences between the environmental B-GAL enzyme and the pure commercial enzyme. Environmental B-GAL was optimally active at pH 7.8. Two temperature optima were observed at 35 and 55 degrees C, respectively. B-GAL activity was strongly inhibited by silver and copper ions. While calcium and ferrous ions at lower concentrations (50-100mgl(-1)) increased the enzyme activity, a reduction was observed at higher concentrations (200mgl(-1)). Sodium hypochlorite, normally used in rural areas to disinfect water gradually decreased B-GAL activity at concentrations between 0 and 5600ppm for both the commercial and environmental enzymes. B-GAL from the environment behaved differently from its commercially available counterpart.
Wutor
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VC
Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
Togo
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CA
Pletschke
B I
BI
D015415:Biomarkers; D002254:Carbonates / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D002733:Chlorophenols; D019343:Citric Acid / Q000494:pharmacology; D003373:Coumaric Acids / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004784:Environmental Monitoring / Q000379:methods*; D005697:Galactosides; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013431:Sulfates / Q000494:pharmacology; D013696:Temperature; D014871:Water Microbiology; D014873:Water Pollutants / Q000302:isolation & purification / Q000494:pharmacology; D001616:beta-Galactosidase / Q000378:metabolism*
D015415:Biomarkers; D002254:Carbonates; D002712:Chlorides; D002733:Chlorophenols; D003373:Coumaric Acids; D005697:Galactosides; D008670:Metals; D009566:Nitrates; D013431:Sulfates; D014873:Water Pollutants; D019343:Citric Acid; C074184:chlorophenol red galactopyranoside; D004492:Edetic Acid; C004999:ferulic acid; D012973:Sodium Hypochlorite; D001616:beta-Galactosidase