This lecture covers the principles of microbial growth and metabolism, focusing on topics such as Liebig's law of the minimum, growth experiments with varying concentrations of nitrogen and carbon sources, biomass concentration, and the influence of C:N ratio on growth. It also discusses the use of multiple substrates simultaneously, the chemostat as a tool to study carbon limitation, and the sequential growth pattern with mixtures of carbon substrates. Additionally, it explores the influence of temperature, pH, osmolarity, and oxygen on microbial growth, as well as the enzymes involved in detoxifying oxygen derivatives.