Abstract
In the present study, genomic analysis of a previously reported carbon dioxide (CO2) sequestering bacterium Serratia sp. ISTD04 was performed along with exopolysaccharide (EPS) production. Genomic analysis identified key and accessory enzymes responsible for CO2 sequestration. EPS synthesis genes were discovered in the genome and identified 8 putative clusters responsible for lipopolysaccharide, stewartan, emulsan, polysaccharide B, capsular polysaccharide and fatty acid-saccharide production. The production of EPS was found to be 0.88 ± 0.08, 1.25 ± 0.13 and 1.44 ± 0.10 g L−1 on glucose, bicarbonate (NaHCO3) and NaHCO3 plus glucose respectively at pH 7.8. After optimizing process parameters, the EPS production increased more than 3 folds. The morphology of strain and elemental composition of EPS was characterized by SEM-EDX. The functional groups, monomer composition, linkage analysis and structure of purified EPS was characterized by FTIR, GC-MS and 1H and 13C NMR. Glucose, galactose, mannose and glucosamine are the monomers detected in the EPS. EPS was further applied for bioflocculation (kaolin test) and dye removal. The EPS showed 68% ± 0.9 flocculating activity and decolorized cationic dye acridine orange (80%) and crystal violet (95%). The results highlight CO2 sequestration and EPS production potential of Serratia sp. ISTD04 that can be harnessed in future.
Highlights
With the increase in atmospheric carbon dioxide (CO2) concentration, there is disturbance in global climate equilibrium as a result the global temperature is rising at a continuous pace
Serratia has been reported from diverse site and perform various functions such as Serratia fonticola RB-25 isolated from a waste landfill for quorum sensing, Serratia plymuthica and other strains AS12, AS9, S13 and 4Rx13 are associated with plants or plant-growth-promoting activities, Serratia proteamaculans 568 with a detailed genome analysis on chitinase production, Serratia marcescens WW4 isolated from a paper machine, S. marcescens FGI 94 associated with leaf-cutter ant fungus garden and S. marcescens Db11 pathogen of drosophila[4,7,8]
Rising level of atmospheric CO2 could be mitigated by bacterial fixation of CO2 along with production of value added product
Summary
With the increase in atmospheric carbon dioxide (CO2) concentration, there is disturbance in global climate equilibrium as a result the global temperature is rising at a continuous pace. Serratia has been reported from diverse site and perform various functions such as Serratia fonticola RB-25 isolated from a waste landfill for quorum sensing, Serratia plymuthica and other strains AS12, AS9, S13 and 4Rx13 are associated with plants or plant-growth-promoting activities, Serratia proteamaculans 568 with a detailed genome analysis on chitinase production, Serratia marcescens WW4 isolated from a paper machine, S. marcescens FGI 94 associated with leaf-cutter ant fungus garden and S. marcescens Db11 pathogen of drosophila[4,7,8] This genus is known for production of value-added products such as enzymes, biosurfactants, pigments, fatty acids, flavors and polyhydroxyalkanoates[2,3,9]. Identification of genes and enzymes controlling particular process will provide an opportunity to further improve www.nature.com/scientificreports/
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