A low-cost effective media from starch kitchen waste for bacterial cellulose production and its application as simultaneous absorbance for methylene blue dye removal

Daily large quantities of kitchen wastes rich in starchy components are discarded into the environment. The current study documents the use of starchy kitchen wastes (SKW) as a low-cost effective substrate for bacterial cellulose (BC) production and loaded with carbonaceous compounds to remove cationic dyes from wastewater. Box-Behnken design (BBD) was applied to optimize the maximum production of reducing sugars by enzymatic hydrolysis of SKW and the hydrolysate at different concentrations used as precursors for BC biosynthesis using Komagataeibacter hansenii AS.5. SEM, FT-IR, and mechanical properties were performed for BC membranes characterization. The synthesized BC membranes were loaded with either charcoal or graphite and evaluated for removal of methylene blue (MB) as a representative cationic dye. The BBD showed that 148.0 g/l of reducing sugars (54.8% saccharification) can be produced using 24.3% of SKW (84.3 g/l/dry) treated with 2-ml amylase (313 U/ml) at 50 degrees C for 5 h and 40 min. The optimum concentrations of SKW hydrolysate produced 2.11 g/l of BC membranes (0.3 g/l/day). The original and loaded membranes showed absorption capacities of 53, 98.7, and 100% removal of MB using BC, graphite-BC, and charcoal-BC membranes, respectively. Therefore, SKW can be used as alternative medium for BC production and applied successfully for dye removal.

Automated summary

The study shows that using starchy kitchen wastes as a substrate for bacterial cellulose production and loading it with carbonaceous compounds for dye removal is effective. Optimization of enzymatic hydrolysis of the kitchen wastes to produce reducing sugars, which are then used for BC biosynthesis, improves the mechanical properties of BC membranes. Additionally, BC membranes loaded with charcoal or graphite show high absorption capacities for removing cationic dyes from wastewater.