In order to survive, organisms produce small molecules known as ‘primary metabolites’ which help it to grow, develop and reproduce. Examples include nucleic acid used to make DNA, amino acids to make proteins, and simple sugars. Once the organism is established it will often start to produce ‘secondary metabolites’. Secondary metabolites are not vital for survival but have important ecological functions, for example fighting off invaders or increasing the likelihood of sexual reproduction.
Filamentous fungi can produce a wide variety of secondary metabolites with antifungal, antibacterial or even insecticidal properties. The variety and composition of these secondary metabolites varies between and even within species leading to a huge range of diverse substances.