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Use of enzymatic methods for rapid enumeration of coliforms in freshwaters
Author(s) -
George I.,
Petit M.,
Servais P.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.00977.x
Subject(s) - enumeration , enzyme , enzymatic hydrolysis , glucuronide , biology , escherichia coli , beta galactosidase , most probable number , chemistry , microbiology and biotechnology , hydrolysis , bacteria , chromatography , food science , biochemistry , metabolite , mathematics , genetics , combinatorics , gene
Rapid enumeration methods based on the enzymatic hydrolysis of 4‐methylumbelliferyl‐β‐ d ‐galactoside and 4‐methylumbelliferyl‐β‐ d ‐glucuronide were optimized for freshwaters. The enzymes β‐ d ‐galactosidase (GALase) and β‐ d ‐glucuronidase (GLUase) were shown to be already induced in freshwaters when tested, respectively, with the inducers isopropyl‐β‐ d ‐thiogalactopyranoside and methyl‐β‐ d ‐glucuronide. Both enzymatic activities were compared, respectively, with plate counts of total and faecal coliforms in freshwaters. Enzymatic methods and reference plate counts were significantly correlated in log–log plots. Moreover, the GLUase method allowed the detection of viable (presenting a detectable GLUase activity) but nonculturable Escherichia coli.