Biocalorimetric investigation of acid blue 113 dye degradation by staphylococcus lentus in glucose and choline lactate based media

Abstract

Calorimetric measurements can provide a direct and continuous evaluation of the overall biomass activity in a waste water treatment process by providing the bacterial heat production profiles. This is based on the principle that enthalpy changes are linked to every metabolic reaction. The present thesis focuses on determination of the metabolic activity of isolated and identified halo tolerant bacterial strain from marine sea water by reaction calorimetry. Correlations between heat profiles of metabolic activity and various process variables viz., oxygen uptake rate (OUR), bio mass production, substrate uptake and chemical oxygen demand (COD) have been worked out. One of the objectives of this study is to employ the calorimetric data generated for future design and scale up of a bio reactor for treatment of azo dye containing effluents. In order to increase the population of micro organisms a number of choline based biocompatible ionic liquids were screened. S. lentus could be successfully cultivated in an ionic liquid limited (2 g/L) mineral salt medium in a bio reaction calorimeter. S. lentus grew faster, evidence by larger microbial population establishing thus the use of ionic liquids as nutrients . The bio degradation of acid blue 113 by S. lentus was successfully performed in a bio reaction calorimeter for the first time. The relationships observed in power-time profile indicated three distinct phases of the bio process, and suggested simultaneous utilization of glucose (primary) and dye (secondary carbon source) Secretion of azo reductase enzyme enhance the degradation process. The bio chemical energitics and the detailed mechanistic pathway elucidated in the thesis work will be useful for future design of a bio reactor for degradation of dye effluent. This study proved the feasibility of application of calorimetry as an inline analytical tool for monitoring dye degradation process. newline newline newline