Plasmid mediated heavy metal resistances in Enterobacter spp. isolated from Sofulu landfill, in Adana, Turkey
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A total of 15 Enterobacter spp. were isolated from water drainage near the landfill in Sofulu village in Adana and were characterised on the basis of morphological, cultural and biochemical characteristics. The Maximum Tolerable Concentrations of cadmium, copper, chromium and nickel for growth were used to determine metal tolerance of the isolated strains. Among the resistant strains used in this study, Ent-5, Ent-7 and Ent-15 were found to have plasmid resistance to copper and nickel. One resistant strain, Ent-5, functioned as a donor of copper resistance. Copper resistance transferred from Ent-5 to Escherichia coli AB3505 at a frequency of approximetely 2.7 x 10-5 per recipient cell. Transformant strain had one plasmid with the same molecular weight donor strain’s plasmid. These isolates...
Some properties of thermostable xylanase from an Aspergillus niger strain
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A thermostable xylanase was isolated from an Aspergillus niger wild type strain in a liquid Czapek Dox medium, containing oat spelts xylan as the sole carbon source. The molecular mass of the enzyme was estimated to be about 36 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum pH for activity was found to be 7.5. The temperature optimum of the enzyme was found to be 60 °C at pH 7.5. The enzyme remained stable up to 100 °C, yet lost about 50% of its activity after 15 min at this temperature.
Keratinolytic activity of Streptomyces strain BA7, a new isolate from Turkey
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A wild type Streptomyces strain BA7 which was isolated from soil, showed a high keratinolytic activity when cultured on native feather medium. Optimum keratinolytic activity was observed at 50 ºC and pH 8.5 when using fluid supernatant obtained from aerated culture of this organism. The keratinolytic activity was completely stable (100%) between 30 and 60 ºC. The molecular weight of crude enzyme was estimated by SDS-PAGE about 44000 Da. The degradation of intact feathers by Streptomyces sp. BA7 keratinase was obtained after 24 h of incubation at 50 ºC. Keratinolytic activity was partially inhibited by 1,10-phenanthroline, but slightly inhibited by CaCl2, ZnCl2, and SDS. In addition keratinolytic activity was enhanced by DMSO, EDTA, Triton-X 100 and sodium sulphite. Streptomyces strain BA7 ...