Publication: Thermostable α-amylase from moderately halophilic Halomonas sp. AAD21
Abstract
Isılkararlı α-amilaz üreticisi ılımlı halofilik Halomonas sp. AAD21, İzmir’de bulunan Çamaltı Tuzlası’ndan izole edilmiştir. Enzim üretimini arttırmak amacı ile NaCl, karbon ve azot kaynakları optimize edilmiştir. En yüksek enzim aktivitesi azot kaynağı olarak pepton, karbon kaynağı olarak nişastanın kullanıldığı besi yerinde, % 20 NaCl konsantrasyonunda elde edilmiştir. İzole edilen mikroorganizmanın patates kabuklarını da karbon kaynağı olarak kullandığı belirlenmiştir. Karbon ve azot kaynaklarının konsantrasyonu istatistiksel yaklaşımla optimize edilmiş ve α-amilaz aktivitesi 4,07 U $mL^ {-1}$ dak–1 den 26,25 U $mL^ {-1}$ dak–1 değerine yükselmiştir. En yüksek α-amilaz üretimi büyümenin 48.nci saatinde % 20 NaCl, % 4,12 nişasta, % 1 pepton, % 0,2 KCl, % 2 MgSO4·7H2O, ve % 0,03 trisodyum sitrat pentahidrat içeren besi yerinde elde edilmiştir. α-Amilazın optimum sıcaklık ve pH değeri sırası ile 50 °C ve pH 7 olarak belirlenmiştir. Ayrıca enzimin yüksek sıcaklıklarda kararlı olduğu da bulunmuştur. Ham enzim 50 °C ve 60 °C sıcaklıklarda iki saat inkübasyonda aktivitesinin tamamını korumaktadır. 90 °C ise 120 dakika inkübasyon sonunda ise aktivitesinin %70’i korunmuştur.
The moderately halophilic Halomonas sp. strain AAD21, which produces extracellular thermostable α-amylase, was isolated from the Çamaltı Saltern area located in İzmir, Turkey. NaCl, carbon, and nitrogen sources in the growth medium were optimized to enhance α-amylase yield. The highest enzyme yield was measured in the presence of 20% NaCl with peptone as the nitrogen and starch as the carbon sources in the fermentation broth. This microorganism was also found to utilize waste potato peel as a carbon source for α-amylase production. Concentrations of carbon and nitrogen sources were optimized using a statistical approach, and α-amylase activity increased from 4.07 U $mL^ {-1}$ min–1 to 26.25 U $mL^ {-1}$ min–1. Maximum α-amylase production was achieved at the end of 48 h of growth in the presence of 20% NaCl, 4.12% starch, 1.0% peptone, 0.2% KCl, 2% MgSO4·7H2O, and 0.03% trisodium citrate pentahydrate. The optimum pH and temperature of the α-amylase were found to be 7.0 and 50 °C, respectively. The α-amylase synthesized by Halomonas sp. AAD21 was also thermostable. Crude α-amylase did not lose its original activity after 2 h of incubation at 50 °C and 60 °C, and it retained 70% of its original activity after 120 min of incubation at 90 °C.
The moderately halophilic Halomonas sp. strain AAD21, which produces extracellular thermostable α-amylase, was isolated from the Çamaltı Saltern area located in İzmir, Turkey. NaCl, carbon, and nitrogen sources in the growth medium were optimized to enhance α-amylase yield. The highest enzyme yield was measured in the presence of 20% NaCl with peptone as the nitrogen and starch as the carbon sources in the fermentation broth. This microorganism was also found to utilize waste potato peel as a carbon source for α-amylase production. Concentrations of carbon and nitrogen sources were optimized using a statistical approach, and α-amylase activity increased from 4.07 U $mL^ {-1}$ min–1 to 26.25 U $mL^ {-1}$ min–1. Maximum α-amylase production was achieved at the end of 48 h of growth in the presence of 20% NaCl, 4.12% starch, 1.0% peptone, 0.2% KCl, 2% MgSO4·7H2O, and 0.03% trisodium citrate pentahydrate. The optimum pH and temperature of the α-amylase were found to be 7.0 and 50 °C, respectively. The α-amylase synthesized by Halomonas sp. AAD21 was also thermostable. Crude α-amylase did not lose its original activity after 2 h of incubation at 50 °C and 60 °C, and it retained 70% of its original activity after 120 min of incubation at 90 °C.