Isolation and biochemical characterization of bacterial isolates producing different levels of polygalacturonases from various sources

Abstract

Sixty-one bacterial strains were isolated from various sources including soil, water, rotted fruits and vegetables. Preliminary screening for pectinase producing bacterial strains was done by well plate method. Sixteen bacteria giving zones from 08 to 22 mm were selected and subjected to cellular, morphological and biochemical characterization. Further screening of selected strains was done quantitatively by 3,5-dinitrosalicylic acid (DNS) method for polygalacturonase production. Strain Z-AT23, Z-AT33 and Z-AT35 characterized as Bacillus sp. produced maximum amount of enzymes ranging from 1.04 to 2 U/ml. Selected Bacillus strains were also checked out at different temperatures and pH for the enzyme production. All Bacilli hydrolyze more pectin at pH 7.0 to 8.0 but strains Z-AT33 and Z-AT35 produced maximum enzyme at temperature of 42°C and Z-AT23 at 32°C. Key words: Bacillus, 3,5-dinitrosalicylic acid (DNS) method, pectin, polygalacturonase.