Growth and Metabolism of Extremophilic Microorganisms

Abstract

Extremophiles are a group of organisms growing optimally in a wide range of extreme environments. They have the capability of using many different types of nutrients for their growth, but only those heterotrophic extremophilic microorganisms are well studied and included for reviewing in this chapter. The utilization of both carbon and nitrogen sources from environments are essential for their thriving. Their growth rates are relatively comparable to mesophilic/neutrophilic microorganisms except oligotrophs. They also use novel enzymes for metabolizing carbohydrates including polysaccharides and peptides and amino acids. Conventional and also modified central metabolic pathways including Embden–Meyerhof–Parnas, Entner-Doudoroff and Pentose Phosphate pathways and Tricarboxylic Acid cycle are operational. However, which one(s) would be used is dependent on the type of the extremophiles. In general, those that grow on carbohydrates can also on peptides and amino acids or both, but some of them can only grow on peptides and amino acids. Their growth, substrate specificity and connections between the carbohydrates metabolism and peptides and amino acids metabolism are discussed in detail. Understanding their growth and metabolic pathways will provide insight into the future development of applications of extremophilic microorganisms in industrial processes.