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  • [ X ]
    Öğe
    Aktinomisetler tarafından üretilen biyoaktif sekonder metabolitlerin; ribozomal olmayan peptid sentetaz (NRPS) ve poliketid sentaz (PKS) genlerinin kullanılmasıyla moleküler olarak taranması
    (2013) Özakın, Süleyman; Porsuk, Ilknur; Bali, Bülent; Acer, İsmail; Yılmaz, Ebru İnce
    [Abstract Not Available]
  • [ X ]
    Öğe
    A cellulase-free, thermoactive, and alkali xylanase production by terrestrial Streptomyces sp CA24
    (Tubitak Scientific & Technological Research Council Turkey, 2013) Porsuk, Ilknur; Ozakin, Suleyman; Bali, Bulent; Yilmaz, Ebru Ince
    Microbial xylanases have attracted much attention because of their applications in industrial processes during the past few decades. Sixty-five terrestrial actinomycetes previously isolated from rhizospheric soils of endemic plants were tested for their ability in production of xylanase. The results revealed that 33 isolates could degrade xylan on both solid and liquid media. Extracellular xylanase production by these isolates was characterized during their growth in liquid medium. Streptomyces sp. CA24, one of the most active strains, was selected for optimization of xylanase production. The enzyme secretion was enhanced when the medium was supplemented with oat spelt xylan (0.5%) and yeast extract (0.5%) at pH 10.0. Optimization of the culture conditions resulted in a 5-fold enhancement in enzyme production (255 U/mL). The most important characteristic of the enzyme is its production over a broad pH range of 6.0-10.0 during all stationary phases. The cellulase-free xylanase was optimally active at 60 degrees C and almost 90% stable after 4 h at 50 degrees C. The high levels of enzyme production obtained under alkali batch cultivation conditions, coupled with no production of cellulase, suggests the use of the local terrestrial strain Streptomyces CA24 and/or its enzyme in industrial processes such as pulp and paper production.
  • [ X ]
    Öğe
    A cellulase-free, thermoactive, and alkali xylanase production by terrestrial Streptomyces sp. CA24
    (2013) İnce, Ebru Yılmaz; Porsuk, Ilknur; Bali, Bülent; Özakın, Süleyman
    Microbial xylanases have attracted much attention because of their applications in industrial processes during the past few decades. Sixty-five terrestrial actinomycetes previously isolated from rhizospheric soils of endemic plants were tested for their ability in production of xylanase. The results revealed that 33 isolates could degrade xylan on both solid and liquid media. Extracellular xylanase production by these isolates was characterized during their growth in liquid medium. Streptomyces sp. CA24, one of the most active strains, was selected for optimization of xylanase production. The enzyme secretion was enhanced when the medium was supplemented with oat spelt xylan (0.5%) and yeast extract (0.5%) at pH 10.0. Optimization of the culture conditions resulted in a 5-fold enhancement in enzyme production (255 U/mL). The most important characteristic of the enzyme is its production over a broad pH range of 6.0 10.0 during all stationary phases. The cellulase-free xylanase was optimally active at 60 °C and almost 90% stable after 4 h at 50 °C. The high levels of enzyme production obtained under alkali batch cultivation conditions, coupled with no production of cellulase, suggests the use of the local terrestrial strain Streptomyces CA24 and/or its enzyme in industrial processes such as pulp and paper production.
  • [ X ]
    Öğe
    Optimal conditions for production of extracellular protease from newly isolated Bacillus cereus strain CA15
    (2011) Yılmaz, Ebru İnce; Porsuk, Ilknur; Uyar, Fikret; Kızıl, Göksel
    Topraktan alkalen proteaz üreticisi Bacillus sp. CA15 izole edildi. 16S ribosomal RNA gen dizilimine gore bu mikroorganizmanin Bacillus cereus ile çok yakin akraba oldugu tespit edildi. Proteaz üretiminin artisini saglamak için, kültür kosulari; karbon ve azot kaynaklari, metal iyonlari, pH ve isinin etkisi açisindan optimize edildi. En yüksek proteaz üretimi, %1 yagsiz süt tozu, %1 çözünür nisasta ve %0.6 $MgSO _4.7H _2O$ varliginda, baslangiç pH'si 8.0 ve 35°C'de üretilen kültürlerden elde edildi. Bu besiyerinde üretilen hücrelerin, canli hücre sayisinin, mL'de 1.8x108'e vardigi duragan fazda en iyi enzim aktivitesine rastlandi. Inorganik azot kaynaklari varliginda proteaz seviyesinin oldukça düsük oldugu bulundu. Sükroz ve laktozun varliginda da proteaz üretiminin azaldigi tespit edildi. Bacillus sp. CA15 alkalen proteazinin Triton X-100, Tween 20 and SDS'ye karsi son derece dayanikli oldugu gözlemlendi. Enzim aktivitesinin PMSF varliginda inhibe olmasi bu enzimin bir serin proteaz oldugunu düsündürdü.