Biotransformation of acrylamide to acrylic acid carried through acrylamidase enzyme synthesized from whole cells of Bacillus tequilensis (BITNR004)

Abstract

In this study, an amidase-synthesizing and inducible thermotolerant bacterium, Bacillus tequilensis (BITNR004), was investigated for the conversion of acrylamide to acrylic acid, which was subsequently confirmed using various analytical tools. The enzyme, acrylamidase, was found to be intracellular in nature with optimum activity at 50 °C. Further, the whole-cell biocatalyst had a biotransformation efficiency of 63% and 59% at 1 mM and 2 mM acrylamide, respectively, as determined via high performance liquid chromatography, while acrylamide-supplemented synthesis medium only had 13% biotransformation efficiency. The substrate and product were detected via thin-layer chromatography, using methanol and water (3.5:1.5 v/v) as mobile phase. Fourier-transform infra-red spectra revealed the presence of the C = C stretch of the alkenyl group of acrylic acid at the frequency range of 1630–1675 cm−1 and of carboxylate at 1390–1440 cm−1, confirming the bioconversion of acrylamide to acrylic acid. Based on whole-cell catalysis, B. tequilensis (BITNR004) can be exploited for the production of acrylic acid and bioremediation of acrylamide-contaminated waste water.