Culture of the marine cyanobacterium, Lyngbya majuscula (Oscillatoriaceae), for bioprocess intensified production of cyclic and linear lipopeptides.

Cyanobacteria are an ancient and diverse group of photosynthetic microorganisms, which inhabit many different and extreme environments. This indicates a high degree of biological adaptation, which has enabled these organisms to thrive and compete effectively in nature. The filamentous cyanobacterium, Lyngbya majuscula, produces several promising antifungal and cytotoxic agents, including laxaphycin A and B and curacin A. Samples of L. majuscula collected from Moorea Island, Tahiti (French Polynesia) and from the Culture Collection of Algae and Protozoa (CCAP 1446/4) were studied and adapted to large scale laboratory culture (5 l). This constitutes a 100-fold scale-up for the culture of this particular strain of L. majuscula. The effect of culture vessel configurations, growth conditions and media compositions on growth of L. majuscula was examined. Using optimised culture conditions, two strains of L. majuscula are currently being evaluated for their production of secondary metabolites. Results will be compared with those obtained from four environmental extracts. Comparisons were made by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). It was shown that varying the culture conditions under which L. majuscula was grown had the greatest effect on secondary metabolite production, thus providing potential for future bioprocess intensified production.

Identification of the green alga, Chlorella vulgaris (SDC1) using cyanobacteria derived 16S rDNA primers: targeting the chloroplast.

We have tested a set of oligonucleotide primers originally developed for the specific amplification of 16S rRNA gene segments from cyanobacteria, in order to determine their versatility as an identification tool for phototrophic eucaryotes. Using web-based bioinformatics tools we determined that these primers not only targeted cyanobacterium sequences as previously described, but also 87% of sequences derived from phototrophic eucaryotes. In order to qualify our finding, a type culture and environmental strain from the freshwater unicellular, green algae genus Chlorella Beijerinck, were selected for further study. Subsequently, we sequenced a 578-bp fragment of the 16S rRNA gene, which proved to be present within the chloroplast genome, performed sequence analysis and positively identified our solvent-degrading environmental strain (SDC1) as Chlorella vulgaris.