Biodesulfurization is an environmentally friendly and sustainable approach for removing sulfur from coal, significantly reducing sulfur emissions associated with coal combustion. This process relies on specialized microorganisms capable of metabolizing sulfur-containing compounds, thereby converting them into less harmful forms such as sulfate or elemental sulfur. This abstract discusses the design and operational principles of reactors used in biodesulfurization, highlighting various reactor types, including batch, continuous stirred tank reactors (CSTRs), and fluidized bed reactors. Each reactor type offers unique advantages regarding mass transfer, microbial retention, and operational flexibility, influencing the overall efficiency of sulfur removal. Key process parameters such as temperature, pH, oxygen supply, and nutrient availability are critical in optimizing microbial activity and achieving effective desulfurization. Challenges, including the stability of microbial consortia, scaling up from laboratory to industrial applications, and economic competitiveness, must be addressed to enhance the practical implementation of biodesulfurization technologies. Future research directions are outlined, emphasizing the need for innovative reactor designs, integration with renewable energy sources, and the optimization of microbial performance. This chapter covers the importance of reactors in advancing biodesulfurization as a viable solution for cleaner coal utilization and reducing the environmental impact of coal-based energy production.