Isolation of alcohol tolerant, osmotolerant and thermotolerant yeast strains and improvement of their alcohol tolerance by UV mutagenesis
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
In this study, the yeast strains were isolated from grapes by serial dilution technique to determine their alcohol-, sugar-and thermotolerance. 34 wild type yeast strains were isolated and alcohol-, sugar-and thermotolerance of these strains were determined. The maximum alcohol tolerance was found to be 9%(v/v) in yeast strain which is named Y2. Thermotolerance behavior of 6 strains were investigated. The strains were treated with UV light with intervals of 20, 30, 40 and 50 seconds. Selected resistant colonies were investigated for alcohol tolerance. It was found that alcohol tolerance increased from 9%(v/v) to 12%(v/v) on Y2 strain.
Thermostable alkaline protease produced by an Aspergillus niger strain
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A thermostable alkaline protease was isolated from the Aspergillus niger Z1 strain in a liquid Czapek Dox medium, containing casein (1% w/v) as the sole nitrogen source. Enzyme extract was subjected to electrophoresis in SDS-polyacrylamide gel. Two protein bands were seen on polyacrylamide gel. Active enzyme was visualized in a zymogram and protease activity exhibited a molecular mass of 68 kDa on SDS-polyacrylamide gel. The optimum pH for activity was found to be 9.0. The temperature optima of the enzyme was found to be 40 °C at pH 9.0 and it remained stable up to 90 °C, with 48.4% of the original activity retained after heat treatment at 90 °C for 15 min. Proteolytic activity was inhibited by PMSF, but slightly inhibited by SDS.
Electrofusion of Saccharomyces cerevisiae Auxotrophic Mutants of Identical Mating Type Using a Laboratory-Made System
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
Yeast protoplasts from haploid auxotroph strains DC6 (MATα) and FY73 (MATα) were exposed to an inhomogeneous alternating field (AC 200 V/cm). Due to the dielectrophoretic aggregation two or more cells with close membrane contact were formed between the two electrodes. The effects of different DC pulses were investigated to determine critical fusogenic pulse strength. In the results, the maximum fusant cells were obtained only when 8 kV field strengths were applied. These findings showed that the optimum fusogenic pulse strength for yeast protoplasts is 8 kV/cm under our experimental conditions. After fusion, the DNA contents of both hybrid and individual parental strains were compared. The amount of DNA in the hybrid was found to be about twofold higher than that in the individual parental...
Some properties of crude carboxymethyl cellulase of Aspergillus niger Z10 wild-type strain
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A carboxymethyl cellulase enzyme was prepared from a wild type strain of Aspergillus niger Z10. Analyses of the enzyme preparation by SDS-PAGE revealed two protein bands showing cellulolytic activity. The molecular weight of these bands was estimated to be around 83,000 and 50,000. The optimum temperature of the enzyme was observed to be around 40 °C. It was found that the enzyme's activity has a broad pH range between 3 to 9 and 41.2% of the original activity was retained after heat treatment at 90 °C for 15 min.
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 ...
Plasmid-Encoded Heavy Metal Resistance in Pseudomonas sp.
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
No abstract available
A preliminary study on tellurite resistance in Pseudomonas spp. isolated from hospital sewage
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A total of 48 Pseudomonas spp., isolated from the Çukurova University Balcalı Hospital sewage in Adana, were characterized on the basis of morphological, cultural and biochemical characteristics. To improve our understanding of the ecology of tellurite resistance in bacteria, the minimum inhibition concentrations (MIC) of potassium tellurite (K2 TeO3 ) for growth were used to determine metal tolerance of the isolated strains. Most of the strains tolerated to 55 µgr/ml potassium tellurite. Ostrain Ps 37 tolerated relatively high concentrations of tellurite (80 µgr/ml). 27% of the strains possessed plasmid mediated tellurite resistance (Telr ).
Enzymatic properties of a novel thermostable, thermophilic, alkaline and chelator resistant amylase from an alkaliphilic Bacillus sp. isolate ANT-6
Coral, Mutlu Nisa Ünaldı | Coral, Gökhan
A thermostable alkaline α-amylase producing Bacillus sp. ANT-6 was isolated from soil samples. Enzyme synthesis occurred at temperatures between 25 and 45 °C with an optimum of 37 °C. There was a slight variation in amylase synthesis within the pH range 7 and 11 with an optimum pH of 9. The optimum temperatures for amylase production and growth were the same. Analyses of the enzyme by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed a single band, which show amylolytic activity, detected in starch gel. The relative molecular mass of the partial purified enzyme was estimated to be 94 500 Da. The enzyme showed optimum activity at pH 10.5 and 80 °C. The partial purified enzyme was highly active in the alkaline range of pH (9.5–13), and it was completely active up to 100 °C ...