Molecular Characterization of Polygalacturonase Producing Bacterial Strains Collected from Different Sources

Seventy-two bacterial strains were isolated from twenty various sources including soil, water, rotten fruits, vegetables etc. Preliminary screening for pectinase producing bacterial strains was done by well plate method and twenty-six bacterial strains gave zones on Minimum Salt (MS) medium supplemented with 0.2% pectin. Most of the isolates belonged to plant origin, either rotten fruits or vegetables due to high pectin presence as compared to other samples. Amongst the bacterial isolates, ZP-F5 and ZP-F6 gave the largest zone sizes i.e., 45 mm and 40 mm respectively. All selected strains were subjected to cellular, morphological and biochemical characterization. Polygalacturonase production by the selected strains was measured quantitatively by DNS method. Strain ZP-F5 and ZP-F6 were producing maximum amount of enzymes i.e., 1.85 U/ml and 1.86 U/ml respectively. Identification of pectinase producing bacteria was confirmed by amplification and sequencing of their 16S rDNA gene. The sequences obtained were BLAST which revealed that ZP-F5, ZP-F6, ZP-F14, ZP-F24 and ZP-F25 were found homologous to Bacillus. Whereas, ZP-F10, ZPF16 and ZP-F18 were homologous to Klebsiella veriicola, Brevibacillus laterosporus, Ewingella americana respectively. In the present study, other than Bacillus species some of the novel strains obtained like Klebsiella veriicola, Brevibacillus laterosporus, Ewingella americana, Providencia vermicola and Klebsiella oxytoca demonstrated significant levels of pectinolytic enzymes capable of hydrolyzing pectin.