Comparative Study of Exopolysaccharide Production from Thermophilic and Autotrophic Microbial Sources — 100a — Allison Kahler¹, Grayson Glass^1, Kelly M. Sutko¹, and Tanvi Govil¹

¹ Karen M. Swindler Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD, USA

Humans produce more than one million tons of plastic waste every year. The use of petroleum-based products is causing harm to the planet by contributing to global warming as well as polluting ecosystems. Bio-based polymers offer a safe alternative in both production and disposal. A common biopolymer called exopolysaccharides (EPS) can be produced cost-effectively on waste products using microorganisms and can be produced in high amounts. EPS are structurally diverse molecules with beneficial properties such as biocompatibility, biodegradability, hydrophilicity, and activities including anti-inflammatory, antioxidant, anticancer, antibacterial, immune-modulating, and prebiotic. These characteristics enable a wide range of useful applications of EPS. In this study thermophilic EPS production was optimized for yield and the extraction quality from two different microbial sources were analyzed for potential further uses. EPS from the thermophilic bacterium Geobacillus sp. EP1 was produced using xylose as a carbon source. EP1 produced 0.83g/L of EPS after 5 days of incubation at pH 7 and a temperature of 60°C. The production process was further scaled up to 3L and the FTIR analysis of EPS confirmed the functional groups of carbohydrates, proteins, lipids and DNA. Additionally, EPS from the autotrophic cyanobacterium Synechosystis sp. 6803 was synthesized at 30°C in BG11 medium and extracted for comparison. Further characterization of the properties of the EPS from Geobacillus sp. EP1 and Synechocystis sp. 6803 could provide a variety of applications in polymer science. One potential application includes their use as polymer replacements or composite blends to synthesize more sustainable and environmentally friendly packaging, medical devices, and agricultural films.

Keywords: Biodegradable Polymers; Microbial Exopolysaccharides; Production; Geobacillus; Synechosystis.

South Dakota Mines
Dr. Tanvi Govil