The first phase of the project is
focused on bacterial strains selection from marine environments capable of production
polyhydroxyalkanoates (PHA) granules. A number of 155 strains from MICROGEN
Microbial Collection were tested using Red Nile fluorescence. Thus, we managed
to select three PHA producers, subsequently confirmed by GC-MS, also
identifying polymer type for the tested conditions. Selected strains were
taxonomically identified based on ribosomal RNA 16S as Loktanella sp. P2, Granulosicoccus
sp. P4, Sulfitobacter sp. P5.
These strains along with ones from the Norway partner, Halomonas sp., Pseudomonas
sp., Roseobacter sp., were
subjected to metabolic assays comprising API and BIOLOG tests. Resulting data
revealed special nutritional demands of tested marine bacteria, oligotrophs for
many carbon and nitrogen sources. Thus, we faced several problems when adapting
our marine isolates to laboratory conditions, requiring a more detailed
analysis of growth media. PHA production was evaluated in a volume of 250 mL,
variating the temperature and carbon source. Detection and quantification of
PHA granules was conducted based on Red Nile fluorescence, using a 96 well
plate reader, also determining cellular density. These assays managed to
emphasize the high PHA production potential of MICROGEN Bacterial Collection
tested strains. For biotechnological approach, Roseobacter sp., was selected for batch cultures in a 2L bioreactor,
recording a lower fluorescence then 250 mL cultures. New isolates from the
Black Sea were tested, and from 22 strains only four were identified as PHA
producers for selected conditions. Thus, we conclude that all our activities
were successfully accomplished.
