Bacterial Nanocellulose from Side-Streams of Kombucha Beverages Production: Preparation and Physical-Chemical Properties

• Published in: Polymers Vol. 9; no. 8; p. 374
• Main Authors: Dima, Stefan-Ovidiu, Panaitescu, Denis-Mihaela, Orban, Csongor, Ghiurea, Marius, Doncea, Sanda-Maria, Fierascu, Radu Claudiu, Nistor, Cristina Lavinia, Alexandrescu, Elvira, Nicolae, Cristian-Andi, Trică, Bogdan, Moraru, Angela, Oancea, Florin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18-08-2017; MDPI
• Subjects: Bacteria; bacterial nanofibrils; Beverages; Cellulose; Cellulose fibers; Chemical properties; Crystal structure; Crystalline cellulose; Crystallinity; Fermentation; Fourier transforms; Infrared analysis; Infrared spectroscopy; Kombucha membranes; Light diffraction; microfluidization; nanocellulose; Photon correlation spectroscopy; Purification; spray-drying; Tea; Thermogravimetric analysis; Transmission electron microscopy; X ray fluorescence analysis; X-ray diffraction; Yeast; bacterial nanofibrils; Kombucha membranes; nanocellulose; microfluidization; spray-drying
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym9080374

We focused on preparing cellulose nanofibrils by purification, separation, and mechanical treatment of Kombucha membranes (KM) resulted as secondary product from beverage production by fermentation of tea broth with symbiotic culture of bacteria and yeast (SCOBY). We purified KM using two alkaline solutions, 1 and 4 M NaOH, which afterwards were subjected to various mechanical treatments. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were employed to evaluate the purification degree, the size and aspect of cellulose fibrils after each treatment step, the physical-chemical properties of intermediary and final product, and for comparison with micro-crystalline cellulose from wooden sources. We determined that 1 M NaOH solution leads to approx. 85% purification, while a higher concentration assures almost 97% impurities removal. XRD analysis evidenced an increase in crystallinity from 37% to 87% after purification, the characteristic diffractograms of Iα and Iβ cellulose allomorphs, and a further decrease in crystallinity to 46% after microfluidization, fact correlated with a drastically decrease in fibrils' size. FTIR analysis evidenced the appearance of new chain ends by specific transmission bands at 2941 and 2843cm
.