Adaption strategies of extremophiles and the construction of wastewater treatment systems driven by extremophiles.

Unconventional wastewater (such as high-salinity brine, acidic mine drainage, industrial wastewater with extreme temperatures, and highly saline-alkaline wastewater) shares characteristics similar to Earth's extreme environments. Microorganisms in extreme environments rely on unique adaptation mechanisms to drive elemental cycling, providing a new direction for the treatment of unconventional wastewater. This article reviews the tolerance mechanisms of extremophiles in adverse environments and expounds on the correlation between the tolerance mechanism and the potential requirements for wastewater treatment. A comprehensive discussion on the adaptation mechanisms of extremophiles corresponding to several common types of unconventional wastewater are conducted. Additionally, it summarizes the general tolerance mechanisms of microorganisms, including the utilization of special cell structures, quorum sensing, and substrates/genes/electrons exchange. The potential mechanisms of electro/magnetic inducibility in enhancing microbial stress resistance are discussed. This article explores the application potential of extremophiles in wastewater treatment, from the perspective of "bottom-up" and "top-down" approaches to constructing synthetic microbial communities. The contributions of emerging technologies are analyzed such as genetic engineering, direct application of extremophiles and extreme extracellular polymer substances, and microbial community construction to develop wastewater treatment systems. Prospects are made in terms of the future directions of the application of extreme microorganisms with artificial intelligence for wastewater treatment. Finally, the challenges in the in-situ research, genetic engineering limitations, and practical wastewater treatment applications of extremophiles are discussed.