Enhanced biocatalytic laccase production using agricultural waste in solid-state fermentation by Aspergillus oryzae for p-chlorophenol degradation

Abstract

Agricultural residues are one of the most cost-effective and readily accessible carbon resources for producing commercially significant enzymes. Several enzymes have been used in different industries like pharmaceuticals, foods, textiles, and dyes that can be generated by various species of microbes found in waste from agriculture. The current research investigated laccase production by Aspergillus oryzae utilizing agricultural wastes. Physical and chemical properties, including pH, temperature, sucrose, yeast extract, and copper sulfate levels, were optimized. The utilization of the response surface methodology along with the centralized composite design method, which assesses multiple media parameters and utilizes a two-level experimental approach, aids in determining the variable and its significance in increasing production quality. The centralized composite design enhancement showed that the optimal conditions for highest laccase activity (623.16 U/mL) were pH 7.0, temperature 25 °C, corn cobs as substrate, sucrose (2.0 %), yeast extract (1.0 %), and copper sulfate (0.1 mM) level. The laccase enzyme was optimized using various pH, temperature, metal ions, and inhibitors combinations. The extracted laccase enzyme maximum activity was attained at pH 6.0 and 40 °C. The inclusion of divalent ions can enhance laccase activity, while the use of various inhibitors decreases laccase activity. Under various pH circumstances, the Aspergillus oryzae laccase enzyme can successfully degrade p-chlorophenol. The present study describes statistically validated optimal methodologies for enhancing laccase synthesis, leading to a laccase production technique that is simultaneously highly efficient and economically profitable, with possible use of p-chlorophenol degradation.