Physiology and Biochemistry of Thermophilic Moulds

Abstract

The majority of fungi are mesophiles which grow in the temperature range between 5°C and 37°C, but a small group is capable of growth above 50°C; this latter group has been categorised into thermophilic and thermotolerant forms. Crisan (1964) termed fungi with optimum temperature for growth at or above 40°C as thermophiles. Fungi are the only eukaryotic organisms with upper temperature limit for growth around 60°C (124). In order to understand the phenomenon of thermophily and their ability to grow at elevated temperatures, attempts have been made to study their unique biochemical and physiological characteristics. The aspects, which have been intensively investigated, include their nutritional requirements, growth and metabolism, temperature relationships, lipids, pigments, antibiotics, ultrastructure and enzymes. Efforts have been made to compare these features of thermophilic moulds with those of mesophiles for finding significant differences, if any, which may help to explain their ability to grow at relatively high temperatures. This chapter deals with the extensive literature that exists on physiological and biochemical aspects of the thermotolerant and thermophilic fungi.