WASTES VIA PLACKETT-BURMAN AND BOX-BEHNKEN DESIGNS SHWETHA AND PAVAN KUMAR PINDI
Abstract
The industrial demand for cost-effective and eco-friendly enzyme production has prompted the exploration of microbial systems utilizing agro-industrial residues. This study aimed to optimize amylase production by Bacillus wiedmannii SPPU 4 using statistical experimental designs and low-cost substrates. A total of seven agro-industrial wastes-wheat bran, rice bran, corn steep liquor (CSL), molasses, groundnut cake, sugarcane bagasse, and whey-were screened using Plackett-Burman Design (PBD) to identify the most influential components for amylase synthesis. Subsequent optimization was performed using Central Composite Design (CCD) under Response Surface Methodology (RSM), focusing on the top three substrates: wheat bran (A), CSL (B), and molasses (C). PBD analysis revealed CSL as the most potent factor (p/=/0.001), followed by molasses (p/=/0.002), wheat bran (p/=/0.011), whey (p/=/0.017), and groundnut cake (p/=/0.024). The highest amylase activity (129.8/U/mL) was achieved in PBD Run 4, where all seven substrates were at their high levels. CCD-based modelling yielded a second-order polynomial regression equation with high significance (F/=/93.32, p/