First report of biocellulose production by an indigenous yeast, Pichia kudriavzevii USM-YBP2

Abstract

Abstract Herein, we describe the first report of Pichia strain producing biocellulose (BC). This yeast was isolated from rotten pineapple and was identified as Pichia kudriavzevii USM-YBP2 using 18S rDNA analysis. The formation of pellicle was characterized using a scanning electron microscope (SEM). Based on SEM analysis, pellicles are presented as an interwoven network of fibers. Next, to produce high BC, optimization was conducted using different carbon and nitrogen sources, carbon and nitrogen concentrations, inoculum size, and cultivation condition. The optimized parameters for maximum BC production were as follows: glucose 8.0% (w/v), peptone 2.0% (w/v), yeast extract 0.5% (w/v), disodium phosphate 0.270% (w/v), citric acid 0.115% (w/v), ethanol 0.5% (v/v), and inoculum size 10% (v/v). The production yield is 12.24 ± 0.43 g/L and the productivity of 0.128 g/L/h. Then, BC was further treated using sulfuric acid to destructuring to bionanocellulose (BNC) and was characterized using the transmission electron microscope (TEM), attenuated total reflection-Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) analysis. After acid hydrolysis treatment, BNC showed a spherical shape as in TEM. Interestingly, BNC characteristic band displayed high similarity with cellulose from other bacterial species. Moreover, BNC showed high crystallinity index (∼82%) as estimated using XRD. Thus, our findings substantiated that strain USM-YBP2 showed remarkable BNC production with unique BNC property that can be further explored in various applications.