the invention relates to industrial microbiology , in particular to fermentation technology and especially to fermentation methods for filamentous microorganisms , in particular , filamentous microorganisms such as actinomycetes . the present invention discloses a method for improving the production of a product of interest in a liquid culture of filamentous microorganisms comprising providing the filamentous microorganisms with an agent for altering the morphology of microstructures of the filamentous microorganisms . the invention also relates to a method for improving the production of a product of interest in a liquid culture of filamentous microorganisms comprising altering in the filamentous microorganisms the expression level or copy number of an endogenous agent for altering the morphology of microstructures of the filamentous microorganisms . the invention further provides multiple methods for obtaining a filamentous microorganism with altered , preferably enhanced , fragmentation characteristics . however , a filamentous microorganism with reduced fragmentation characteristics is also included .