Preparation and characterization of cellulose nanocrystals from bacterial cellulose produced in sugar beet molasses and cheese whey media.

Abstract Bacterial cellulose (BC) is gaining considerable attention due to its unique physicochemical and mechanical properties. In this study, BC production by Gluconacetobacter xylinus PTCC 1734 in sugar beet molasses, cheese whey and standard Hestrin–Schramm (HS) media was evaluated. The synthesized BC was hydrolyzed by sulfuric acid to prepare bacterial cellulose nanocrystals (BCNC). The results showed that treated sugar beet molasses led to the highest BC concentration and productivity, followed by treated cheese whey. Structural analysis of BC and BCNC was carried out by Fourier Transform Infrared (FTIR) spectroscopy. The crystallinity index of the BCNC determined by X-ray diffraction (XRD) was higher than BC. The morphological analysis carried out by FE-SEM showed that microfibrils diameter decreases with acid treatment. TEM images confirmed the formation of rod like cellulose nanocrystals having an average diameter and length of 25 ± 5 and 306 ± 112 nm, respectively. In conclusion, food industrial byproducts can be used as cost-effective culture media to produce BC for large-scale industrial production and isolated cellulose nanocrystals are useful in the fabrication of bio-nanocomposite films for food packaging applications. Highlights • The use of beet molasses and cheese whey media not only decrease the production cost of BC but also upgrade these by products • Highest BC concentration and productivity was obtained in molasses medium • Bacterial cellulose nanocrystals (BCNC) was synthesized by sulfuric acid hydrolysis • FTIR analysis showed the increasing of crystalline regions after chemical treatment process • FE-SEM micrographs confirmed that the average diameter of BC microfibrils decreased as the result of acid treatment. [ABSTRACT FROM AUTHOR]