The remarkable resilience and adaptability of microorganisms to extreme environments offer a wealth of potential for addressing climate change through carbon dioxide (CO2) fixation. This review explores bacterial carbon fixation pathways, encompassing both natural and engineered synthetic mechanisms, to elucidate their role in catalysing climate change mitigation efforts. Natural pathways, such as the Calvin-Benson-Bassham cycle, Reductive tricarboxylic acid cycle, Reductive acetyl-CoA cycle, 3-Hydroxypropionate cycle, Hydroxypropionate/4-hydroxybutyrate cycle, Dicarboxylate/4-hydroxybutyrate cycle, RHP pathway, Reverse oxidative tricarboxylic acid cycle, and Natural reductive glycine pathway, are discussed alongside engineered synthetic pathways like the Crotonyl-CoA/ethylmalonyl-CoA/hydroxybutyryl-CoA cycle, Synthetic formolase pathway, and Synthetic acetyl-CoA pathway. As balancing ecosystem dynamics and nutrient cycling play vital roles in maintaining the balance of carbon dioxide levels in the atmosphere, understanding the microbial process of carbon fixation and storage in diverse ecosystems is crucial. Improving the knowledge of biological carbon fixation will help in the effective application of these microorganisms in different niches. The chapter highlights the significance of microbial carbon fixation in climate change regulation and addresses the challenges and future perspectives associated with utilizing microbial potential for effective climate change mitigation strategies.