Mrunalini Patil, Pranali Shete, Swati Kokare and Shubhada Nayak
Abstract
Bacterial exopolysaccharides (EPS) represent a diverse class of biopolymers with wide-ranging applications in food, pharmaceutical, and nutraceutical industries. To explore novel bacterial EPS, this study focused on isolation of EPS producing bacteria from the rhizosphere region of sweet potato plantation. A total of 25 morphologically different mucoid isolates were recorded whose extracted EPS was confirmed using the Molisch test. Selected isolates EPS were partially purified and quantified for which EPS Sp21 led to highest dry weight yield of 2.40 g/l of media. The exopolysaccharide from EPS Sp21 had a carbohydrate content of 84.69±0.031µg/ml and protein content of 7.50±.04µg/ml as determined by phenol sulphuric acid and Lowryâs method respectively. The extracted EPS UV visible analysis demonstrated absorption in the range of 200 nm to 400 nm with maxima at 230 nm indicative of CâO, CâC, or CâOâC sugar backbone bonds. Zeta Potential studies of purified exopolysaccharide confirmed that EPS is anionic with highly poly-dispersive nature. Further, scanning electron microscopic appearance of EPS was highly irregular, layered, porous and spongy. Energy-Dispersive X-ray analysis (EDX) demonstrated predominance of carbon (55.2 wt.%) and oxygen (40.7 wt.%) with other trace elements. 16SrRNA sequencing and BLAST analysis of EPS Sp21 exhibited similarity to Enterobacter cloacae.