Synthesis and Characterization of Microencapsulated Bacteria for Application in Enhanced Oil Recovery Technique

This article describes synthesis and characterization of polyelectrolyte complexes (PEC) microcapsules consisting of xanthan-chitosan polymers to encapsulate Rhodococcus ruber and their application in improving microbial enhanced oil recovery (MEOR) process, for the first time. A 1% concentration of polymers (chitosan and xanthan) and a pH 5 was found to be most suitable to synthesize well defined microcapsules. Physicochemical characterization of microcapsules was done using FTIR, DSC and UV-Vis spectroscopy. The swelling studies delineate the behaviour of microcapsules in oil as well as in water. The viability and release studies of the microbes in the microcapsules were conducted at pH 4.2, 5.2 and 6.2. Results showed a steady release of the cells and their viability inside the microcapsule, suggesting the feasibility of their application in oil recovery. To further elucidate the potential applications of the formulated microcapsules, a proof of concept experiment was performed. An in-lab oil reservoir prototype was developed and oil recovery tests were performed with the encapsulated and non-encapsulated bacteria. An increase in the recovery was observed with the encapsulated bacteria thus suggesting potential capacity of these microcapsules in developing MEOR process.