Bacterial nanocellulose from side-streams of Kombucha beverages production: Preparation and physical-chemical properties

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We focused on preparing cellulose nanofibrils by purification, separation, and mechanical treatment of Kombucha membranes (KM) resulted as a 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), Fouriertransform 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 microcrystalline cellulose from wooden sources. We determined that the1 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 I? and I? cellulose allomorphs, and a further decrease in crystallinity to 46% after microfluidization, in fact, correlated with a drastic decrease in fibrils' size. FTIR analysis evidenced the appearance of new chain ends by specific transmission bands at 2941 and 2843cm?1

Keywords: nanocellulose, kombucha membranes, spray-drying, microfluidization, bacterialnanofibrils

Country: Romania

Citation: Polymers 2017, 9, 374; doi:10.3390/polym9080374

Study Mailing Address:
INCDCP ICECHIM, 202 Splaiul Independentei, Bucharest 060021, Romania

Date Updated: February 18, 2021

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