The present book 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. The bio-chemical energetics and the detailed mechanistic pathway elucidated in the book 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.