Abstract:Thermophilic cyanobacteria, as primary producers in extreme high-temperature ecosystems, has evolved unique adaptive mechanisms under high-temperature (> 45 ℃) and mineral-enriched extreme conditions in hot springs. For carbon assimilation, their dependence on ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) and its carboxysome microcellular compartment overcomes the inhibition of the enzyme activity at high temperatures by enhancing substrate affinity and CO2 concentration efficiency. At the level of energy metabolism, the thermally stabilized photosystem Ⅱ (PSⅡ) complex and the electron transport chain are reconstructed to maintain the synergy between light and dark reactions at high temperatures. In terms of stability regulation, metabolic homeostasis is achieved through dynamic glycogen storage, antioxidant defense, and molecular chaperone networks. Systematic analysis of the carbon metabolism-environmental adaptation coupling mechanisms, carboxysome structural dynamics, and PSⅡ thermal protection mechanisms of thermophilic cyanobacteria will facilitate synthetic biology-driven engineering of thermophilic carbon-fixing chassis cells (e.g., heterologous expression of thermophilic Rubisco or design of thermostable electron transport chains), thereby expanding the direct bioconversion of high-temperature industrial waste gas and the biotreatment of heat-containing wastewater and promoting the innovation of micro biotechnology for extreme environments in pursuit of carbon neutrality.
