Application of Response surface methodology in industrial wastewater treatment using Alpha-amylase from Bacillus amyloliquificiens grown on bread waste

Abstract

Food waste is characterized as food loss by consumers or merchants as a result of inadequate storage and a lack of awareness. The objective of this study is to produce alpha-amylase on bread brown waste (BBW) and bread white waste (BWW) using solid medium and submerged fermentation and to use the amylase produced in the treatment of industrial wastewater. B. amyloliquificiens showed the highest starch hydrolysis ratio (SHR) and -amylase activity on both solid medium and submerged fermentation. The production of α-amylase was optimized using the one-factor-at-a-time (OFAT) method. By inoculating BBW (pH 7.0) with 2% (2.3 106 CFU/mL) B. amyloliquificiens and incubating for 24 hours at 37°C and 200 rpm while submerged, the maximum alpha-amylase activity was approached, reaching 695.2 U/mL. The crude enzyme was collected and immobilized on calcium alginate beads. It had an efficiency (IE%) of 96.6% and 88.5% remaining activity after 12 runs of useability. The interaction between the process parameters and the ideal conditions was determined using the Box-Behnken (BBD) statistical design. The quadratic model and one-way analysis of variance (ANOVA) were produced by the BBD to represent the degradation of starch. The experimental values obtained for starch hydrolysis (%) were found to be very close to the predicted response values. According to the design, the ideal conditions were pH 9, 45°C, and 70% and 27.5 U/mL, respectively, of starch after 15 minutes, indicating a high value for the coefficient of determination, R2 (0.83). The alkaliphilic and thermophilic nature of the enzyme activity was confirmed by the ANOVA results, which showed that the quadratic model created from the RSM was statistically significant for starch hydrolysis. At concentrations ranging from 10.9 to 695.1 U/mL, the crude-amylase enzyme was used in the 15-minute desizing process for clothing at 45°C and pH 9.0, and it was discovered to maintain 96.3% of the desizing efficiency. From the study, it could be concluded that the RSM can be a useful tool for optimization and moderation of the process parameters to maximize starch hydrolysis in industrial wastewater treatment.