Bacterial Cellulose Production in Dried Apricot Extract Medium: Experimental/Theoretical Characterization and Application in Yeast Immobilization for Dye Removal

Bacterial cellulose (BC) was produced in dried apricot extract medium (DAEM) by <i>Gluconacetobacter xylinus</i> <i>B759</i>. The BC yield obtained from DAEM containing 0.5 g of glucose after 10 days of incubation at 30 °C was determined as 9.67 g/L. BC was used as an immobilization matrix for <i>Saccharomyces cerevisiae</i>. First, structural characterizations of BC and BC-yeast were carried out. Also, their surface and morphological properties were examined by SEM and atomic force microscopy. Yeast attachment and growth kinetics were also evaluated experimentally and theoretically. This yeast-immobilized BC (BC-yeast) membrane was used for removal of textile dye, Reactive Blue 171 (RB 171). The results showed that yeast was successfully immobilized on BC and could be effectively used for dye removal. When 12 lyophilized BC-yeast samples were used, 52% and 21% dye removal values were obtained under static and shaking (150 rpm) conditions, respectively. These values were 49% and 50% for wet BC-yeast samples after 24 h, respectively. Additionally, density functional theory calculations were performed to elucidate the interactions responsible for the adsorption of RB 171 dye onto the BC structure, and it was shown that the RB 171 structure is energetically very strong and favorably bound to the BC surface. It was found that BC-yeast was highly effective for RB 171 removal. Therefore, the BC produced in DAEM could be used as an immobilization matrix and as a low-cost, effective, and alternative adsorbent for the removal of dyes from dye-containing wastewaters.