This paper examines the physiological and metabolic characteristics of sulfate-reducing bacteria (SRB), focusing on their energy-generating pathways, electron transfer mechanisms, and roles in the biogeochemical sulfur cycle. Through both heterotrophic and autotrophic metabolisms, SRB can reduce sulfur compounds to sulfide under anaerobic conditions and play a vital role in bioremediation processes and maintaining sulfur balance in the environment. The study also analyzes the energy conservation pathways, sulfate reduction mechanisms, and microbial interactions of SRB across diverse ecosystems. In addition, the biotechnological applications of SRB in treating industrial wastewaters rich in sulfate and heavy metals, as well as the environmental challenges associated with their activity, such as biocorrosion and hydrogen sulfide production, are discussed. Recent advances in utilizing SRB for modern environmental technologies highlight their potential in pollution control, metal recovery, and the synthesis of valuable bio-based compounds. This study provides a comprehensive perspective on the ecological significance, biotechnological potential, and related challenges of SRB.