Set-Up of Bacterial Cellulose Production From the Genus Komagataeibacter and Its Use in a Gluten-Free Bakery Product as a Case Study

Abstract

The use of bacterial cellulose (BC) in food systems is still limited due to production costs. Nine clones belonging to <i>Komagataeibacter hansenii</i>, <i>Komagataeibacter nataicola</i>, <i>Komagataeibacter rhaeticus</i>, <i>Komagataeibacter swingsii</i>, and <i>Komagataeibacter xylinus</i> species were screened for cellulose productivity in growth tests with five different carbon sources and three nitrogen sources. The water-holding and rehydration capacities of the purified cellulose were determined. The structure of the polymer was investigated through nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy and X-ray diffraction (XRD) analysis, and observed by scanning electron microscope (SEM). Natural mutants of <i>K. rhaeticus</i> LMG 22126^T and <i>K. swingsii</i> LMG 22125^T showed different productivity. The factors "bacterial isolate" and "nitrogen source" significantly affected the production of cellulose (<i>p</i> < 0.01) rather than the factor "carbon source" (<i>p</i> = 0.15). However, on average, the best conditions for increasing yield were found in medium containing glucose and peptone. Water-holding capacity (WHC) values ranged from 10.7 to 42.3 (<i>g</i> _water/<i>g</i> _cellulose) with significant differences among strains (<i>p</i> < 0.01), while the rehydration capacity varied from 4.2 to 9.3 (<i>g</i> _water/<i>g</i> _cellulose). A high crystallinity (64-80%) was detected in all samples with Iα fractions corresponding to 67-93%. The ATR-FT-IR spectra and the XRD patterns confirmed the expected structure. BC made by GVP isolate of <i>K. rhaeticus</i> LMG 22126^T, which was the strain with the highest yield, was added to a gluten-free bread formulation. Results obtained from measurements of technological parameters in dough leavening and baking trials were promising for implementation in potential novel foods.