Streptomycetes in microcultures: growth, production of secondary metabolites, and storage and retrieval in the 96-well format. Antonie van Leeuwenhoek 78

Mycelium-forming Streptomyces strains were grown in one milliliter liquid micro-cultures in square deep-well microtiter plates. Growth was evaluated with respect to biomass formation and production of secondary metabolites which were found to be very similar in the micro-cultures, bioreactor, and shake flask cultivations, respectively. Despite repetitive sampling and extensive growth on the walls of the wells, no cross contamination occurred. Furthermore, we successfully employed cold storage at 20 C of spore suspensions (in the 96-well format), directly prepared from cultures grown on agar in the microtitre plate. Cultures were retrieved by replicating aliquots from the frozen spore suspensions. Abbreviations: act – actinorhodin biosynthetic genes; ARO – aromatase; CDW – cell dry weight; CYC – cyclase; DMAC – 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid; KR – ketoreductase; MOPS – 3[N