Production and characterization of bacterial cellulose from kombucha-fermented soy whey

Abstract

Bacterial cellulose (BC) is a high-strong cellulose with high-purity produced by bacteria. The aim of this study was to explore the feasibility of using tofu soy whey as a novel and cheap culture medium to produce bacterial cellulose (BC) through the fermentation of kombucha. In this study, the statistical optimization of the culture medium for producing BC from kombucha was carried out by selecting different parameters. A three-level, three-factor Box-Behnken design (BBD) was used to determine the optimal levels for three significant variables (sucrose addition, kombucha inoculation amount and fermentation temperature). According to the results, the optimal fermentation conditions were found as follows: sucrose addition 8.5%, kombucha inoculation amount 10%, fermentation temperature 32℃, the BC yield can be up to 4.20 g/100 mL (D.W) under 11d fermentation. Besides, the BC was determined with strong tensile strength and water absorption capacity. By scanning electron microscopy (SEM) observation, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) determination, BC produced by soy whey and Hestrin-Schramm (HS) medium were compared. The results showed that BC produced from soy whey has a typical cellulose structure, characteristic peaks of typical functional groups of cellulose, and crystal diffraction peaks of type I natural cellulose. In conclusion, this study utilized the nutrients in the soy whey to obtain a high yield of bacterial cellulose, make full use of industrial waste water, which was more environmentally friendly and cheaper.Graphical