초록
<P><B>Abstract</B></P> <P>Including additives in the culture media during bacterial cellulose (BC) biosynthesis is a traditional method to produce BC-based nanocomposites. This study examines a novel fermentation process, which is to co-culture <I>Gluconacetobacter hansenii</I> (<I>G. hansenii</I>) with <I>Escherichia coli</I> (<I>E. coli</I>) under static conditions, to produce BC pellicles with enhanced mechanical properties. The mannose-rich exopolysaccharides (EPS) synthesized by <I>E. coli</I> were incorporated into the BC network and affected the aggregation of co-crystallized microfibrils without significantly changing the crystal sizes of BC. When co-culturing <I>G. hansenii</I> ATCC 23769 with <I>E. coli</I> ATCC 700728, which produced a low concentration of EPS at 3.3 ± 0.7 mg/L, the BC pellicles exhibited a Young’s modulus of 4,874 ± 1144 MPa and a stress at break of 80.7 ± 21.1 MPa, which are 81.9% and 79.3% higher than those of pure BC, respectively. The growth dynamics of the two co-cultured strains suggested that the production of BC and EPS were enhanced through co-culturing fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> BC nanocomposite with improved mechanical properties was produced by co-culturing G. hansenii with <I>E. coli</I> ATCC 700728. </LI> <LI> The mannose-rich EPS from <I>E. coli</I> affected the aggregation of co-crystallized microfibrils but not altered BC’s crystal sizes. </LI> <LI> The growth of <I>G. hansenii</I> was improved in co-culture. </LI> </UL> </P>