ISOLATION PROPERTIES AND POTENTIAL APPLICATIONS OF THERMOPHILIC ACTINOMYCETES

Actinomycetes comprise a large and diverse group of largely mycelial bacteria, many of which are important ecologically and are exploited commercially for the production of natural products such as antibiotics and enzymes. Thermophilic species are also known but these are relatively poorly studied compared with the predominant mesophilic genera. This article describes habitats and methods for isolation and recovery of thermophilic actinomycetes, such as Streptomyces, Thermomonospora, and Thermoactinomyces. General properties are discussed with respect to mesophilic species and their potential for the production of enzymes concerned with hydrolysis of complex macromolecules described. Their ability to synthesize antibiotics is reviewed and the advantages of production at high temperatures illustrated with reference to granaticin production by Streptomyces thermoviolaceus. Work with some of the better studied thermophilic species indicates the presence of novel properties. More intensive investigations of their properties, as well as those of actinomycetes that grow at extremes of pH or salinity, may lead to the discovery of novel natural products.