Production and Characterization of Extracellular Polysaccharide from Anoxybacillus flavithermus AAG-61 with Resistance to Sulfamethoxazole and Ofloxacin

Extracellular polysaccharide producers from Kursunlu (Manisa) thermal spring were identified and a total of nine isolates were selected. One isolate was selected based on its strong mucoid structure and identified as Anoxybacillus flavithermus (AAG61) by MALDI-TOF MS. A. flavithermus AAG-61 had multiple antibiotic resistance to both Sulfamethoxazole, and Ofloxacin. The polysaccharide produced by A. flavithermus AAG-61 was purified and characterized. It was an anionic heteropolysaccharide containing rhamnose, mannose, arabinose, and glucose. The polysaccharide was water-soluble and had a concentration of 3.1 g/L carbohydrate and 0.11 g/L protein. The EPS consisted of 32% carbon, 7% nitrogen, 5% hydrogen, and traces of sulfur (0.6%). The presence of protein and sulfur in the polysaccharide was confirmed by FT-IR. Zeta potential, mobility, and conductivity values were -8.3 (± 0.5) mV, -0.65 (± 0.04) µmcm/Vs, and 1.57 (± 0.08) mS/cm. The crystallinity pattern was also determined by XRD analysis. No effect on the viability of the human fibroblast cell line was observed.