Purification, Characterization, and Potential of Saline Waste Water Remediation of a Polyextremophilicα-Amylase from an Obligate HalophilicAspergillus gracilis

Abstract

An obligate halophilicAspergillus graciliswhich was isolated from a hypersaline man-made saltern from Thailand was screened for its potential of producing extracellularα-amylase in the previous studies. In this study theα-amylase was extracted and purified by the help of column chromatography using Sephadex G-100 column. Presence of amylase was verified by SDS-PAGE analysis, showing a single band of approximately 35 kDa. The specific activity of the enzyme was found to be 131.02 U/mg. The Lineweaver-Burk plot showed theVmaxandKmvalues of 8.36 U/mg and 6.33 mg/mL, respectively. The enzyme was found to have the best activity at 5 pH, 60°C, and 30% of NaCl concentration, showing its polyextremophilic nature. The use of various additives did not show much variation in the activity of enzyme, showing its resilience against inhibitors. The enzyme, when tested for its use for synthetic waste water remediation by comparing its activity with commercial amylase in different salt concentrations showed that theα-amylase fromA. graciliswas having better performance at increasing salt concentrations than the commercial one. This shows its potential to be applied in saline waste water and other low water activity effluents for bioremediation.