Catalase Test

If the Catalase Test indicates that the enzyme is present at significant or problematic concentrations, plate counts should be performed on stock samples prior to bleaching to determine the level of bacterial contamination. Toxicity studies can then be performed to select a biocide program that will control the bacteria. 

Regular monitoring with the Catalase Test and/or plate counts will let you know if yoru program is effectively controlling catalase-producing bacteria. 

Note The fiber float test is simple and quick to run. Keep in mind that the problem must be massive in order for the biocide application to be economical and to justify the program costs. 

An unfortunate consequence of life in oxygenated environments and, hence, respiratory metabolism is the formation of oxygen s highly reactive reduction product, hydrogen peroxide. Hydrogen peroxide (H2O2) is formed via the following coupled reactions  

Because flavoproteins and oxidases are ubiquitous among living organisms, those that grow in the presence of oxygen (aerobes) contain (minimially) the enzyme catalase to detoxify the peroxide as its formed  

The test for catalase and, hence, oxidative metabolism is easily accomplished and, along with Gram stain reaction, provides valuable information regarding the bacteria s identity. 

Hydrogen peroxide (3% v/v). Prepare a 1 10 dilution of stock (30% v/v) hydrogen peroxide in distilled water. Alternatively, 3% (v/v) H2O2 is available in pharmacies and most markets. 

Yeast culture to serve as positive control (see Supplemental Note 

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Phenotypical isolates from purified water shall be characterized. Biochemical testing (such as oxidase test, urease test, catalase test, citrate test, coagulase test, and indole test) and commercial test kits (such as API tests) and reagents may be used for conformation of some unique isolates. 

Both the oxidase and catalase tests are very rapid, producing results in 2-3 minutes. Details may be found in the chapter on biochemical methods. 

For those unfamiliar with the catalase test, preparation of a positive control, using Saccharomyces, is useful. This preparation should exhibit a strong catalase. 

The reader is referred to Chapter 1 Procedure 1.5.2 for background and details regarding the catalase test. 

Nutrient agar 35°C-37°C 24 h Negative catalase test after addition of hydrogen peroxide [69]... 

The first iodimetric catalase test is attributed to Jolles (196) who, in 1903, described an end point technique the H 0 was titrated after 2 hours of reaction time and without using a buffer. Thirty years later Balls and Hale (45) described the first significant improvement in the iodimetric assay and their technique remains the most useful one to date. The historical development of the KI titration method can be followed in Table VI. The iodimetric estimation, however, is generally less satisfactory than the titration with permanganate because the iodine liberated in the test can both react with and be adsorbed on the proteins present. Also, the preparation of the KI and NasSjOs solutions is somewhat more tedious than that of KMn04. 

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