Phenazines in the Environment: Microbes, Habitats, and Ecological Relevance

Abstract

Phenazines, the pigmented, redox-active metabolites produced by certain fluorescent pseudomonads, streptomycetes, and members of a few other bacterial genera, have long been recognized for their broad-spectrum antibiotic activity. Much has been learned in recent years about the synthesis of these compounds and the diverse roles they play in the physiology of the microorganisms that produce them, but surprisingly little is known about their presence and turnover in natural ecosystems or their significance in microbial habitats. Phenazine producers are found throughout nature in association with plant and animal hosts and in terrestrial, freshwater, and marine habitats, and may reach sufficient numbers that the phenazines they produce can be extracted directly from environmental samples. This chapter focuses on recent reports that highlight the diversity of habitats from which phenazine producers have been recovered and the significance of the phenazines they produce in the ecosystems in which they reside.