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.
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.
Separation of megabased-sized DNA molecules of Aspergillus niger using pulsed field gel electrophoresis
Coral, Gökhan | Coral, Mutlu Nisa Ünaldı
In this study, the chromosomal DNAs were extracted from Aspergillus niger Z10 wild type strain and these DNAs were separated using the contour clamped homogeneous electric field gel electrophoresis (CHEF) system. This system is laboratory-made and is operated by a computer program. Total DNAs resolved into five distinct chromosomal bands. The size of the chromosomes was estimated as being between 3.3 Mb to 6.4 Mb.
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.