Treatment of industrial wastewater containing amides using novel bacterium in semi-continuous reactor

Abstract

The work initially isolates and identifies the bacteria from pharmaceutical industrial wastewaters having amidase activity and then immobilizes and optimizes the reaction conditions adopting variants of batch, fed batch and continuous reactor system for maximum bioconversion of acetamide to acetohydroxamic acid. The maximum acyltransferase activity was obtained in 100 mM potassium phosphate buffer (pH 7.5) with substrate concentration 0.850 mmoles of acetamide and 1.7 mmoles of hydroxylamine hydrochloride with resting cells 0.94 mg (cell dry weight) (0.322 Uml-1) for 20 min at 55 °C. It had showed broad substrate specificity. Acetamide was the best substrate followed by acetonitrile. Industrial wastewater contains a large number of metal ions thus in view of future application of this research for real pharmaceutical wastewater treatment, the effect of a various metal ions on the immobilized cells was studied. Among the various metal ions and inhibitors, AgNO3 had only severely affected the enzyme activity. The short operation time of the proposed process, coupled with the possibility of an enzyme reuse during several cycles, are effective tools to implement this economically competitive semi-continuous reactor for amide biodegradation in pharmaceutical wastewaters.