Isolation of Cellulolytic Bacteria from Mangrove Sediment in Dumai Marine Station Riau and the Antibacterial Activity against Pathogens

Abstract

Abstract Cellulolytic bacteria are a group of bacteria that have an ability to degrade material containing cellulose and have potency to inhibit the growth of pathogenic bacteria. The bacteria can be found in soil or sediment in the mangrove ecosystem. This research aimed to: 1) isolate cellulolylitic bacteria from mangrove sediments in Dumai Marine Station, of Riau, Indonesia, 2) to examine the antagonism against pathogenic bacteria (Escherichia coli, Pesudomonas aeruginosa, Vibrio alginolyticus), and 3) to identify and the phenotype and genetic characters of the potential isolates. The bacteria were isolated on Zobell Marine Agar 2216 added with carboxymethyl cellulose (CMC). Cellulolytic index value was obtained by reducing clear zone diameter with the bacterial colony diameter. Disc diffusion agar method was used to examine antagonism of selected isolates against pathogens. The isolates were observed for the colony and cell morphology, biochemical and genetically characters. Twenty four isolates showed cellulolytic activity and index values ranged from 1.00 to 2.86 and 0.01 to 2.12, respectively. Nine of selected isolates performed ranges of zone inhibition against E. coli, P. aeruginosa and V. alginolyticus from 2.38 ± 0.21 mm to 3.58 ± 0.83 mm, 2.75 ± 0. 59 mm - 4.81 ± 0.57 mm and 2.28 ± 0.45 mm - 4.68 ± 1.40 mm, respectively. Based on the 16S rDNA sequence analysis, three cellulolytic isolates indicated similarity to Bacillus toyonensis (99.53 %).