Electrospinning Nanofibres of Pullulan Extracted From Phylloplane Fungus, Aureobasidium Pullulans

Abstract Aureobasidium pullulans isolated from the phylloplane of Peltophorum tree, produced pullulan, 24 an extracellular polysaccharide. It was grown on three different carbon sources, sucrose, wheat 25 bran and cotton stalk dust, for maximizing the pullulan yield. A. pullulans (67.4 gL-1) had the 26 highest yield followed by A. pullulans MTCC 1991 (63.68 gL-1). Pullulan was characterized by 27 X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area analyzer, DSC and NMR. 28 Electrospinning of pullulan blended with poly (vinyl alcohol) (PVA) produced bead-less 29 nanofibres. The optimized parameters for electrospinning were 25 kV applied voltage, 0.5 mL/h 30 flow rate, 18% polymer concentration (pullulan + PVA) and 150 mm tip-to-collector distance. 31 The pullulan nanofibre was characterized by SEM, AFM, BET, contact angle measurement, DSC 32 and CIE color space analyzer. A maximum surface area of 183.4 m2/g while the minimum 33 nanofibre diameter (79 ± 19 nm by SEM) was obtained for the electrospun mat of commercial 34 pullulan + 40% PVA. This work signifies the importance of pullulan extracted from an isolate of 35 Peltopohorum tree for conversion to high surface area nanofibres by electrospinning process.