Oligotrophs: Microbes at Low Nutrient Levels

Extremophiles are microbes capable of adaptation, survival and growth in extreme habitats that are supposed as adverse or lethal for other life forms. Like various other extreme environments, bacteria are also reported to grow in a minimum medium without additional carbon and energy sources. The microorganisms that can grow in low nutrient concentrations, or in the apparent absence of nutrients, are known as oligotrophs. In contrast, copiotroph bacteria grow fast where the resource or nutrient is abundant. Many of these oligotrophs alter their morphology (surface to volume ratio) with changing nutrient concentrations. The diverse oligotrophs have been isolated from the different low-nutrient habitats, such as marine, soil, desert soil, ultra-pure water, etc. The molecular and physiological properties of diverse oligotrophs and their applications in bioremediation are also studied. Oligotrophs would also be suitable for in situ bioremediation, because such microorganisms can grow on the contaminated site without additional nutrients. Remarkably, the adaptive capabilities of oligotrophs convert them into an attractive source for industrial purposes. Thus, oligotrophs have a biotechnological potential, orienting researchers to attempt their isolation and studies from various low-nutrient habitats. The objective of this chapter is to discuss the characteristics, adaptations and applications of oligotrophs. nbsp;