Phylogenetic diversity and biotechnological potentials of marine bacteria from continental slope of eastern Arabian Sea

Abstract

Marine environments are substantially untapped source for the isolation of bacteria with the capacity to produce various extracellular hydrolytic enzymes, which have important ecological roles and promising biotechnological applications. Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. A number of marine hydrolases have been described, including amylases, lipases and proteases, which are being used extensively for biotechnological applications. The present study was carried out to isolate marine bacteria from continental slope sediments of the eastern Arabian Sea and explore their biotechnological potential. Among the 119 isolates screened, producers of amylases (15%), caseinases (40%), cellulases (40%), gelatinases (60%), lipases (26%), ligninases (33%), phytase (11%) and Malachite Green dye degraders (16%) were detected. Phylogenetic analysis based on 16S rRNA gene sequencing showed that predominant marine sediment bacteria possessing more than four enzymatic activities belonged to the phyla Firmicutes and Proteobacteria, was assigned to the genera Bacillus, Planococcus, Staphylococcus, Chryseomicrobium, Exiguobacterium and Halomonas. Biodegradation of the dye Malachite Green using the liquid decolorization assay showed that both the individual cultures (Bacillus vietnamensis, Planococcus maritimus and Bacillus pumilus) and their consortium were able to decolorize more than 70% of dye within 24 h of incubation. This is the first report on diversity and extracellular hydrolytic enzymatic activities and bioremediation properties of bacteria from continental slope sediment of eastern Arabian Sea.

Biodegradation of Malachite Green in Milkfish Pond Sediments

“…These results indicate that Tenacibaculum is more persistent in the experimental conditions and contributes more to MG degradation. In addition, four bacterial genera (Achromobacter, Halomonas, Comamonas, and Marinobacter), which have been reported as MG-degrading bacteria, increased in the experiments with the addition of bacterial strains M10 and M12 [31,[38][39][40]. Another two bacterial genera (Pseudomonas and Flavobacterium), which have been reported as MG-degrading bacteria, increased in the experiments without the addition of bacterial strains M10 and M12 [17,41].…”

“…As the temperature increased, Kordiimonas and Methylophaga became major bacterial genera in the milkfish pond sediments. One bacterial genus (Halomonas) that has been reported as MG-degrading increased in proportion as the temperature rose (Figure 2B) [31].…”

Evolutionary Strategies of Highly Functional Catalases for Adaptation to High H2O2 Environments

“…The purified VKTA exhibits 395,000 U/mg protein under standard reaction conditions (30 mM H 2 O 2 , pH 7), with a V max and K m of 8.0 × 10 5 μmol H 2 O 2 /μmol heme/s and 35 mM for H 2 O 2 , respectively, as determined spectrophotometrically. The catalytic efficiency k cat /K m of VKTA is 2.3 × 10 7 /s/M, which is the highest among reported clade 3 catalases owing to the low K m value [31]. Additionally, because of the fragility of V. rumoiensis S-1 T cells, high affinity to H 2 O 2 and high catalytic efficiency are required for protection of the cells.…”

“…Exiguobacterium spp. are distributed in various environments, including marine environments [30,31]. Therefore, strain T-2-2 T may have originated from marine environments or organisms.…”

Bioprospecting potential and secondary metabolite profile of a novel sediment-derived fungus Penicillium sp. ArCSPf from continental slope of Eastern Arabian Sea

“…Gelatinase activity was detected by addition of 1% mercuric chloride. The formation of clear zone around the fungal strain was noted (Farha et al 2018).…”