Development and characterization of bacterial cellulose nanocomposites from de-pectinated sugar beet pulp...

A biorefinery concept based on sugar beet pulp is presented in this work for the production of pectin and bacterial nanocellulose. Residual sugar beet pulp solids (SBPR) derived after free sugars and pectin recovery were evaluated for onsite enzyme production by solid-state fermentation with the fungal strain Aspergillus awamori. Optimization of SBPR hydrolysis via response surface methodology yielded 81.4 % glucan and 25.3 % hemicellulose hydrolysis (pH 6.0, 55.0°C). The SBPR hydrolysate was employed in bacterial cellulose (BC) production, where aeration increased BC production by 65 %, leading to 4.6 g/L BC, with 0.33 g/g yield and 0.65 g/(L·d) productivity. The produced BC (30-50 nm width and 5-20 μm length) was further modified into bacterial cellulose nanocomposites (BNC) with a high crystallinity index (>92 %), 0.45 % sulfation and clean of bacterial residues. These BNC with a 30-50 nm width and high aspect ratio (∼10), are promising for use as reinforcing agents in polymer matrices.