Sono-Bio-Desulphurization of Liquid Fuel using Free and Immobilized Cell

In view of environmental concerns, the production of clean energy is one of the most critical issues in modern years to accommodate the growing energy needs of society (domestic usage), agriculture, and industry. Clean energy can be accomplished in several ways. A possible solution to this issue is to use renewable energy sources such as solar, wind, and nuclear power universally. The use of conventional techniques to produce energy by the combustion of fossil fuels has adverse effects on the environment due to the emission of greenhouse gas that contributes to global warming. The conventional method adopted by petroleum refinery industries has not been successful for profound desulphurization to achieve low sulphur contents. To overcome this, several new alternative chemicals, and physical and biological techniques have been developed to meet ultra-low sulphur fuel in the last two decades. Microbial desulphurization is one of the emerging alternative techniques that can remove the organo-sulphur compounds from fuels. The limitation of microbial desulphurization is the slow kinetics and it can be overcome by combining it with other desulphurization processes (hybrid system), such as the ultrasound-assisted processes. This chapter presents a critical account of research in different facets of ultrasound-assisted biodesulphurization. The microbial desulphurization process involves the use of free or immobilized microorganisms over the PU foams and the application of enzymes for desulphurization of DBT. The enzymes or proteins can act as catalysts to degrade sulphur compounds present in fuels. The present chapter also deals with the ultrasound-assisted microbial and enzymatic pathways. The concurrent analysis of experimental results on enzymatic biodesulphurizarion along with simulation results of cavitation bubble dynamics provides more insight into the actual mechanism of ultrasound on microbial and enzymatic desulphurization process.