Phenotypic and Genotypic Characterization of a Novel Soil Isolated Strain of Pantoea Genus with High EPS Production

Biopolymers are derived from animal, plant or microbial biomass. They may be, lipopolysaccharides, polysaccharides, proteins, glycolipids, or polyhydroxyalkanoates and well capable to environmental applications. Polysaccharides produced by microorganisms can be generally categorized by their biological functions into intracellular storage polysaccharides (glycogen), capsular polysaccharides (for example, alginate xanthan, cellulose, alginate, etc). Biopolymers are the main components of the cell, generally consisting of 90% dry cell substance. The mail cell monomers are amino acids, monosaccharide, and nucleotides which from such polymers as proteins, polysaccharides, and ribonucleic and deoxyribonucleic acids. Bacterial polysaccharides are natural, renewable, nontoxic, Eco-friendly and biodegradable biopolymers which make them attractive for many industrial applications. These biopolymers can be used as stabilizers, emulsifiers, thickeners, gelling and coating agents in food and cosmetic industries, bioflocculants and biosorbents in the environmental field; moreover, biopolymers showed wide applications in biomaterials, prebiotics and encapsulating agents in the health sector. In the present study, a novel strain of Pantoea genus with high EPS production was isolated from the soil. Macroscopic analyses and microscopic features were conducted in order to characterize the isolated bacterium. Phenotypic methods including biochemical assays, ribosomal DNA restriction analysis, and 16srDNA sequence analysis were performed. Total genomic DNA was extracted from novel strain using a bacterial genomic DNA extraction lit (DNeasy & tissue handbook) as manufacture protocol. The 16S rRNA gene was amplified from the genomic DNA by PCR. Then, the obtained 16S rRNA gene sequence was compared with those of other bacteria in Gen Bank using the BLAST program (http://blast.ncbi.nlm.nih.gov/blast.cgi) to determine the phylogenetic affiliation of novel strain. A phylogenetic tree based on the 16S rRNA gene sequence of new strain and other related bacterial strains was constructed using MEGA 5.0 software. Macroscopic analyses on colony morphology indicated yellow, circular, entire margin, convex with elevated center mucoid; and also the colony was opaque and shiny with the size of 2-3 mm. Microscopic features demonstrated gram negative short bacilli occur in irregular clusters. Phenotypic and genotypic characterization confirm that novel strain shared the highest 16S rRNA gene sequence similarity to Pantoea thecola NBRC 110557 by 98.97%. Interestingly, this strain is capable of using wastes such as cheese whey and molasses as a substrate for EPS production. These kinds of the substrate are commercially reasonable to produce EPS and considerably reduce carbon source cost. The produced EPS represented significant potential for different industrial applications such as soil stabilization, pharmaceutical carriers, and heavy metal removal

کلیدواژه ها:

Bacterium isolation ، Genotypic ، EPS ، Pantoea ، Phenotypic