Microbial Coculture and OSMAC Approach as Strategies to Induce Cryptic Fungal Biogenetic Gene Clusters

This chapter provides an overview of successful examples that highlight the power of the one strain many compounds (OSMAC) approach or of microbial cocultivation for an elicitation of bioactive fungal natural products that resulted either in an enhanced accumulation of constitutively present compounds, and/or in an accumulation of new natural compounds missing in axenic control cultures. The OSMAC concept is applied to explore changes of microbial metabolite profiles influenced by changing fermentation conditions, such as different media, different temperature regimes, different culture vessels, and other factors. Another approach that has proven highly successful in triggering the activation of silent biosynthetic gene clusters is the cocultivation of two or more different microbes together in one culture vessel rather than maintaining pure cultures. This strategy mimics the natural microbial ecosystem, defined as microbiome, where the microorganisms interact with each other in synergistic and/or antagonistic relationships, which are the driving ecological forces for triggering secondary metabolite biosynthesis.