Bio-Prospecting Xylose-Utilizing, Exopolysaccharide (EPS)-Producing Bacteria and EPS Quantification through Submerged Fermentation using Xylose as the Major Carbon Source

Abstract

Many microorganisms are capable of producing exopolysaccharides (EPS) while utilizing simple sugars and hexoses. These EPS find applications in diverse fields such as agricultural biotechnology, pharmaceuticals, textiles, and the food industry. However, there is a gap in studies focusing on EPS-producing bacteria that can utilize pentoses like xylose. To address this, the study aimed to prospect bacteria capable of utilizing xylose as a primary carbon source for EPS production. Samples were collected from agricultural soil, dump sites, saline soil, cement-contaminated soil, fresh cow milk, cow dung, and yogurt. These samples were serially diluted and cultured in a salt-based medium with xylose as the sole carbon source. Slimy and mucoid colonies, indicative of potential EPS-producing isolates, were selected and identified using morphological, biochemical tests, and the VITEK 2 Automated Identification System. Quantification of EPS production was performed through submerged fermentation, using xylose as the sole carbon source. The mean heterotrophic bacterial count of xylose-utilizing bacteria ranged from 2.1×1062.1 \times 10^6 CFU to 3.5×1083.5 \times 10^8 CFU per gram of analyzed samples. The identified isolates included members of the genera Staphylococcus, Enterobacter, Kocuria, Klebsiella, Enterococcus, Serratia, and Burkholderia. The quantities of EPS produced varied between 0.04 g/L and 2.0 g/L. Notably, Enterobacter cloacae (D1 and D2) and Klebsiella oxytoca (D2 and G1) were the highest EPS producers. This study demonstrates that bacteria capable of utilizing xylose for EPS production can be isolated from diverse environmental and biological sources, highlighting their potential for industrial applications. Further research into optimizing growth conditions and xylose utilization could enhance EPS yields and support the development of sustainable alternatives to hexose-based EPS production.