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Keywords:

  • Staphylococcus lentus;
  • acid blue 113;
  • azo dye;
  • biocalorimeter;
  • bioenergetics;
  • degradation pathway

Abstract

Bioreaction calorimetric studies of degradation of the dye acid blue 113 by Staphylococcus lentus are reported for the first time. The heat released during the dye degradation process can be successfully measured using reaction calorimeter. Power time and oxygen uptake rate (OUR) profile followed each other suggesting that heat profiles could monitor the progress of the dye degradation in biocalorimetry. The shifts observed in power–time profile indicated three distinct phases of the bioprocess indicating simultaneous utilization of glucose (primary) and dye (secondary carbon source). Secretion of azoreductase enzyme enhanced the degradation process. Optimization of aeration and agitation rates was observed to be vital to efficient dye degradation. The degradative pathway for acid blue 113 by S. lentus was delineated via high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography coupled with mass spectrometry (GC-MS) analyses. Interestingly the products of degradation were found to have low toxicity, as per cytotoxicity measurements. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012