• KSBB Journal
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• v.22 no.5
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• pp.356-361
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• 2007

Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Although some cyanobacteria produce lethal toxins such as microcystins and anatoxins, some may be useful either for development into commercial drugs or as biochemical tools. Detection of unknown secondary metabolites was carried in the present study by a screening of 98 cyanobacterial strains from Cyanobiotech GmbH in order to establish a screening process, isolate pure substances and determine their bioactivities. A degenerated polymerase chain reaction technique as molecular approaches has been used for general screening of NRPS gene and PKS gene in cyanobacteria. A putative PKS gene was detected by DKF/DKR primer in 38 strains (38.8%) and PCR amplicons resulted from a presence of NRPS gene were showed by MTF2/MTR2 primer in 30 strains (30.6%), respectively. A screening of interesting strains was performed by comparing PCR screening results with HPLC analyses of extracts. HPLC analysis for a detection of natural products was performed in extracts from biomass. 5 strains were screened for further scale-up processing. 7 pure substances were isolated from the scale-up cultures and tested for bioactivities under consideration to purity, amount and molecular weight of substances. One substance isolated from CBT 635 showed cytotoxic activity. This substance may be regarded as Microcystin LR.