Research Projects

Rapid and efficient CO₂ capture requires the development of a suitable technology which can effectively sequester CO₂ and convert it into valuable products. So far, the process of CO₂ sequestration has been known to be performed mainly through various chemical routes. However, the synthetic CO₂ capturing technologies that are well established in industrial processes (such as absorption using liquid sorbents, adsorption by solid sorbents or membrane separation) suffer from various disadvantages, high cost being the major problem. Nature has evolved highly complicated and sophisticated mechanisms in biological systems for CO₂ sequestration; a resource that remains principally unused. Majorly two classes of organisms have been studied in this regard e. g., photoautotrophs and chemoautotrophs. However, commercially viable CO₂ sequestration and utilization technology using photoautotrophs remains a distant dream owing to various bottlenecks. Chemoautotrophs have the unique ability to fix CO₂ via oxidation of inorganic compounds as the source of energy and hence, free from the requirement of sunlight. Molecular hydrogen, reduced nitrogen (NH₄+ and NO₂−), sulfur (e.g., H₂S and S₂O₃2−) and metals (e.g., Fe2+ and Mn2+) serve as the electron donors for these bacteria, whereas oxygen and nitrate mostly serve as electron acceptors. Although, hydrogen-oxidizing bacteria has faster growth rate among autotrophic micro-organisms, the requirement of substantial amount of H₂ gas makes them infeasible for industrial application. Therefore, the development of a highly efficient CO₂-fixing chemoautotrophic bacterial platform without the requirement of hydrogen and sunlight is a prerequisite for commercially feasible CO₂ capturing and utilization technology. In the present research, we propose to develop a sustainable technology for efficient sequestration of CO₂ and its subsequent conversion into value added product e.g. ethanol without requirement of sunlight and H₂. We aim to achieve this overall goal by combinatorial approach of (i) screening of chemoautotrophs, (ii) directed metabolic engineering for conversion of CO₂ into ethanol, (iii) Adaptive Laboratory Evolution (ALE) towards improved CO₂ fixation ability of the strain and (iv) Process development (medium and process engineering) towards improved growth and ethanol titer in a 10 L airlift reactor. The proposed research not only aims to mitigate greenhouse gas emissions but also promotes sustainability and addresses biomanufacturing through development of eco-friendly and high value products.