초록
<P><B>Abstract</B></P> <P>The production and crystallinity of <SUP>13</SUP>C bacterial cellulose (BC) was examined in static culture of <I>Komagataeibacter xylinus</I> with different chemical and physical stimuli: the addition of NaCl or cloramphenicol as well as exposure to a magnetic field or to UV light. Crystalline BC biosynthesized under each stimulus was studied by XRD and solid state <SUP>13</SUP>C NMR analyses. All treatments produced BC with enhanced crystallinity over 90% (XRD) and 80% (NMR) compared to the control (83 and 76%, respectively) or to Avicel (77 and 62%, respectively). The XRD data indicated that the crystallite size was 80–85 Å. Furthermore, changes on the allomorphs (I<SUB>α</SUB> and I<SUB>β</SUB>) ratio tendency of BC samples addressed to the stimuli were estimated using the C4 signal from <SUP>13</SUP>C NMR data. These results showed a decrease of the allomorph I<SUB>α</SUB> (3%) when BC was biosynthesized with UV light and chloramphenicol compared to control (58.79%). In contrast, the BC obtained with NaCl increased up to 60.31% of the I<SUB>α</SUB> allomorph ratio.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Enhanced crystallinity of <SUP>13</SUP>C-bacterial cellulose (BC) under different stimuli was achieved. </LI> <LI> Changes on the BC crystallinity addressed to the stimuli were evaluated by XRD and NMR. </LI> <LI> BC crystallinity enhancement was mostly associated with increased crystallite size. </LI> <LI> A simple method by NMR to evaluate changes in I<SUB>α</SUB> and I<SUB>β</SUB> in the crystalline phase of BC was described. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>