Investigation of extracellular highly thermostable starch hydrolyzing activity from a novel thermophilic bacterium Anoxybacillus gonensis A4


ÇOLAK A. , Col M., ÇANAKÇI S. , Belduez A. O. , Omarov I.

ASIAN JOURNAL OF CHEMISTRY, cilt.20, ss.1577-1587, 2008 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 20 Konu: 2
  • Basım Tarihi: 2008
  • Dergi Adı: ASIAN JOURNAL OF CHEMISTRY
  • Sayfa Sayıları: ss.1577-1587

Özet

A novel hot spring thermophile, Anoxybacillius gonensis A4 was investigated in terms of capability of starch degradation and characterization of its thermostable hydrolytic activity. It was observed that A. gonensis A4 has a hydrolytic enzyme responsible for starch hydrolysis with a 0.6 R-f value. The extracellular crude preparation was characterized in terms of pH and temperature optima and stabilities, kinetic parameters and inhibition/activation behaviour toward some chemicals and metal ions. Starch agar assay showed that A. gonensis A4 secreted a hydrolytic enzyme and K-m and V-max values of its activity were found to be 1.88 mg/mL and 0.54 U/mg protein, respectively. The optimum temperature and pH, for A. gonensis A4 hydrolase was 50 degrees C and 7.5, respectively. The enzyme activity was not significantly changed by incubating crude extract solution at the temperature range from 20 to 80 degrees C for 60 h. pH-stability profile of the crude enzyme for 24 h at 4 degrees C of incubation temperature showed that the enzyme had good stability over 65% at all investigated pH range from 4.5-9.5. The efficiency of metabisuiphite on crude amylolytic activity indicated that A. gonensis A4 produce a hyrolaze having disulfide bridges were essential for starch hydrolysis.