Isolation and Partial Characterisation of Thermophilic Cellulolytic Bacteria from North Malaysian Tropical Mangrove Soil

Abstract

This study reports the biodiversity of thermophilic cellulolytic bacterial strains that present in the north Malaysian mangrove ecosystem. Soil samples were collected at the four most northern state of Malaysia (Perak, Pulau Pinang, Kedah and Perlis). The samples obtained were first enriched in nutrient broth at 45°C and 55°C prior culturing in the carboxymethylcellulose (CMC) agar medium. Repeated streaking was performed on the CMC agar to obtain a pure culture of each isolate prior subjecting it to hydrolysis capacity testing. The isolates that showing the cellulolytic zone (halozone) were sent for 16S rRNA sequencing. Total seven isolates (two from Perak, three from Kedah, another two were from Perlis and Penang each) showed halozone. The isolate (KFX-40) from Kedah exhibited highest halozone of 3.42 ± 0.58, meanwhile, the one obtained from Perak (AFZ-0) showed the lowest hydrolysis capacity (2.61 ± 0.10). Based on 16S rRNA sequencing results, 5 isolates (AFY-40, AFZ-0, KFX-40, RFY-20, and PFX-40) were determined to be Anoxybacillus sp . The other two isolates were identified as Bacillus subtilis (KFY-40) and Paenibacillus dendritiformis (KFX-0). Based on growth curve, doubling time of Anoxybacillus sp . UniMAP-KB06 was calculated to be 32.3 min. Optimal cellulose hydrolysis temperature and pH of this strain were determined to be 55°C and 6.0 respectively. Addition of Mg 2+ and Ca 2+ were found to enhance the cellulase activity while Fe 3+ acted as an enzyme inhibitor.

Molecular identification of bacterial isolates from the rhizospheres of four mangrove species in Kenya

“…Bacteria are considered as potent and functional enzyme producer due to their high growth rate, availability of multi-enzyme complexes and stability at the harsh condition (Ladeira et al, 2015). Several studies have demonstrated diverse useful potential of bacteria isolated from mangrove ecosystems (Behera et al, 2014a;Kunasundari et al, 2017;Naresh et al, 2019;Soares Júnior et al, 2013). Our findings confirm that mangrove rhizospheres are a source of diverse bacterial communities that have been shown to produce secondary metabolites.…”

First Insights into the Microbiome of a Mangrove Tree Reveal Significant Differences in Taxonomic and Functional Composition among Plant and Soil Compartments

“…This enzyme is reportedly produced by both bacteria (e.g., Bacillus spp.) [52] and fungi (Fusarium spp. and Aureobasidium spp.)…”

Invited Review: Biodiversity of Plant Polysaccharide-Degrading Bacteria in Mangrove Ecosystem

“…Especially, the genus Bacillus belonging to the phylum Firmicutes was dominant genus. In addition, several thermostable cellulases were also isolated (Kalaiselvi et al 2013;Naresh et al 2019). Meanwhile, based on metagenomic approaches, bacteria belonging to three phyla, Proteobacteria, Firmicutes and Actinobacteria were detected as cellulose-degrading bacteria, and a novel β-glucosidase and a endoglucanase were cloned and characterized (Li et al 2012;Mai et al 2014;Thompson et al 2013;Ottoni et al 2017).…”

“…and one Paenibacillus sp. from four mangrove areas in northern part of Malaysia (Perak, Pulau Pinang, Kedah and Perlis) (Naresh et al 2019). In addition, a novel actinobacterium, Streptomyces monashensis, which can produce antioxidants, exhibited cellulose degradation (Law et al 2019).…”