Microbial Growth and Iron Reduction: Environmental Implications

This lecture covers the intricate relationship between microbial growth and iron reduction in environmental contexts. It begins with an introduction to polyhydroxyalkanoates (PHAs), highlighting their role as biodegradable storage materials produced by various bacteria under nutrient-limiting conditions. The instructor discusses the dynamics of microbial growth, particularly under dual carbon and nitrogen limitations, and how these conditions influence the accumulation of PHAs. The lecture transitions to the significance of iron cycling, detailing the processes of iron reduction and oxidation, and the challenges microorganisms face in utilizing iron as an electron acceptor. Various strategies employed by microorganisms, such as direct contact, electron shuttles, and the production of ligands to solubilize iron, are explored. The instructor emphasizes the environmental implications of these microbial processes, particularly in contexts like acid mine drainage, where iron cycling plays a crucial role in ecosystem dynamics. The lecture concludes with a discussion on laboratory experiments designed to investigate these processes further, providing students with practical insights into microbial iron reduction.