Extremophiles, classified based on the specific extreme conditions they inhabit, encompass a variety of microorganisms that exist in environments with physical or chemical parameters beyond the typical range for most organisms [1]. The primary categories of extremophiles includes thermophiles and hyperthermophiles, psychrophilic and psychrotolerant, acidophilic, alkaliphiles, piezophile, metallophiles, xerophiles, radiophile, micro-aerophile(Table 1, Table 2)[2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13].

Extremophiles, with their unique environmental adaptations and high tolerance for extreme conditions, offer tremendous value in industrial biotechnology. For example, industrial biomining processes for extracting copper, gold and other metals involve the use of Acidithiobacillus ferrooxidans [14]. Deinococcus geothermalis, as an extremely radiation-tolerant thermophilic bacterium, emerges as a prime contender for remediating radionuclide waste, with potential therapeutic applications foreseen from the extremolytes synthesized by these organisms. [15]. Additionally, extremozymes, enzymes from extremophiles, are instrumental in various industrial processes. These enzymes exhibit unique molecular adaptations that enable them to function with remarkable stability and activity under these extreme polar conditions. For example, the extremely tolerant cellulases produced by Paenibacillus tarimensis L88 obtained from the Sahara Desert in southern Tunisia have been shown to be highly functional in a wide pH range (3.0–10.5), high temperatures (up to 80 ℃), and high salt concentrations (up to 5 M NaCl) [16]. Paenibacillus tarimensis is the best candidate for cellulase production, and has broad application prospects in detergent, textile and pulp and paper industry [16].

The remarkable resilience and metabolic capabilities of extremophiles offer significant advantages, such as the ability to operate in harsh industrial conditions, thereby reducing the need for stringent process controls and potentially lowering costs. However, their specialized nature also presents challenges, such as the difficulty in culturing and genetically modifying these organisms for specific industrial needs. Balancing these factors, the future prospects of extremophiles hinge on advancing our understanding and technological capabilities to harness their advantages while mitigating the limitations. This balance will be pivotal in determining their role in the next generation of industrial biotechnological solutions.

In recent years, remarkable progress has been made in NGIB (next generation industrial biotechnology), based on the development and optimization of synthetic biology and fermentation techniques. As a low-cost biological processing technology, the core of NGIB is to use extremophiles as chassis cells to establish an open, non-sterilized continuous fermentation production system, which has the advantages of non-sterile, conservation of energy and resources, high product concentration, simple separation operation, etc. For example, Halomonas, which can carry out open, continuous fermentation and mass production of bioplastics polyhydroxyalkanoate (PHA) and other types of products under high salt and alkali conditions, has gradually become a research hotspot of industrial biotechnology [17]. Extremophiles are gradually becoming a good platform for the development of the next generation of industrial biotechnology.

The economic and environmental benefits of using extremophiles are substantial. Their resilience in extreme environments leads to more efficient industrial processes, reducing operational costs and environmental impacts. These organisms offer eco-friendly alternatives to traditional chemical processes, minimizing the formation of toxic byproducts. However, the special genetic backgrounds and metabolic pathways of extremophiles, due to their unique living conditions, make identification and screening challenging. At present, strain identification technology has been in-depth to the molecular level, gene level detection, including nucleic acid hybridization technology, nucleic acid amplification technology, DNA fingerprinting technology, gene chip technology and high throughput sequencing technology. These molecular identification techniques vary in applicability, with each having its own set of advantages and disadvantages, necessitating careful selection based on experimental conditions and strain characteristics.