Aims: A better understanding of the role of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) in the protection of Aspergillus niger spores against thermal stress. Methods and Results: Conidiospores from A. niger 26 were subjected to wide range of temperatures (30, 50, 60 and 80°C). The stress response was investigated by the determination of spore germination and mycelial growth of survivors under submerged cultivation. Exposure to any temperature above the optimal value induced an increase in SOD and CAT activities. PAGE demonstrated enhanced level of Cu/ZnSOD under stress conditions. We compared the influence of heat shock and superoxide-generating agent paraquat on growth and antioxidant enzyme defence and found different response to the both type of stresses. Conclusions: Heat stress elicits the enhanced synthesis of enzymes whose functions are to scavenge reactive oxygen species. These results suggested an association between thermal and oxidative stress. Significance and Impact of the Study: Evidence is provided for the possibility that oxidative stress plays a major role in the effect of heat in low eucaryotes such as A. niger. This knowledge may be of importance in controlling both fermentation and pathogenicity.

Extremophiles are of significant scientific interest due to their unique adaptation to harsh environmental conditions and their potential for diverse biotechnological applications. Among these extremophiles, filamentous fungi adapted to high-salt environments represent a new and valuable source of enzymes, biomolecules, and biomaterials. While most studies on halophiles have focused on bacteria, reports on filamentous fungi remain limited. This review compiles information about salt-adapted fungi and details their distribution, adaptation mechanisms, and potential applications in various societal areas. Understanding the adaptive mechanisms of halophilic fungi not only sheds light on the biology of extremophilic fungi but also leads to promising biotechnological applications, including the development of salt-tolerant enzymes and strategies for bioremediation of saline habitats. To fully realize this potential, a comprehensive understanding of their ecology, diversity and physiology is crucial. In addition, understanding their survival mechanisms in saline environments is important for the development of astrobiology. The significant potential of applications of halophilic fungi is highlighted.