Bacterial cellulose/hyaluronic acid nanocomposites production through co-culturing Gluconacetobacter hansenii and Lactococcus lactis under different initial pH values of fermentation media

Providing additives into the culture media is a traditional method to manufacture bacterial cellulose (BC) based nanocomposites. This study employed a novel fermentation process, which is to co-culture Gluconacetobacter hansenii (G. hansenii) with genetically modified Lactococcus lactis (L. lactis) under static conditions, to synthesize BC/HA (hyaluronic acid) nanocomposites. The HA concentration produced by L. lactis and the dry weight of BC/HA during co-culture were regulated by the initial pH values of culture media. The incorporation of HA into the cellulose network increased the crystal sizes when the initial pH values were at 7.0, 6.2, and 5.5. The strain at break was also increased while Young’s modulus was decreased when comparing BC/HA to pure BC produced under the initial pH values of culture media at 7.0 and 6.2. When the initial pH value was 4.0, the HA concentration in the culture media exhibited the lowest level observed, which was 20.4 ± 2.3 mg/L. The BC/HA composite synthesized under this condition exhibited an improved Young’s modulus of 5029 ± 1743 MPa from 2705 ± 656 MPa associated with the pure BC. The FESEM images showed that the presence of HA dramatically changed the distribution of ribbon width in BC/HA compared to that of pure BC. The BC/HA produced by co-culture fermentation didn’t need to add extra and expensive HA during production and could be used in biomedical applications such as wound dressing and tissue engineering.