Selective and sensitive detection of pectin lyase activity using a colorimetric test: Application to the screening of microorganisms possessing pectin lyase activity

Several methods have been described for the detection and quantification of polygalacturonase (PG) and pectin lyase (PL) activities. The most frequently used tests are the Nelson method using copper(II) and an arsenomolybdate reagent to detect pc; activity, and the colorimetric method using thiobarbituric acid (TBA) to detect PG activity. We observed that none of these methods are suitable to differentiate between these two enzymatic activities. Therefore, we optimized the test conditions of the TEA method. As a result, the detection of the enzymatic beta -elimination (PL activity) became sensitive and selective. A basic pretreatment at 80 degreesC for 5 min of the solution which contains the pectin fragments of the PL activity furnished aldehydes which were condensed with TEA or its derivatives. After acidification of the medium, a pink fluorescent dye was detected spectrophotochemically (lambda = 550 nm), The interference of galacturonic acid or oligomers resulting from PG activity was completely eliminated. The most sensitive reagent was N-(pyridin-2-yl)-thiobarbituric acid. The application of this method with the new reagent was extended to the screening of microorganisms possessing the pi, activity. The obtained results confirm that Aspergillus niger strain and a Saccharomyces cerevisiae SCPP strain possess this activity, (C) 2001 Academic Press.