Partial purification and characterization of protease enzymes from Bacillus cereus

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Erciyes Üniversitesi, Fen Bilimleri Enstitüsü, TARIM BİLİMLERİ VE TEKNOLOJİLERİ ANABİLİM DALI, Türkiye

Tezin Onay Tarihi: 2020

Tezin Dili: İngilizce

Öğrenci: SADDAM ABDALHAMED BDEWE BDEWE

Danışman: Semih Yılmaz

Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu

Özet:

PARTIAL PURIFICATION AND CHARACTERIZATION OF PROTEASE ENZYMES FROM BACILLUS CEREUS Saddam Abdalhamed BDEWE Erciyes University, Graduate School of Natural and Applied Sciences M.Sc. Thesis, August 2020 Supervisor: Prof. Dr. Semih YILMAZ ABSTRACT Proteases are the major responsible molecules that are involved in the breakdown of protein molecules into simple amino acids. Because of the fact that proteases are used in several industrial and medical sectors, these enzymes are the center of this research interest. Proteases can easily be obtained from plants, animals, and microorganisms. The easiest and cheapest source of proteases is the microorganisms. The Bacillus genus is considered as one of the most studied group in all bacterial classes. The current study was conducted to investigate the specific conditions and other parameters in the production process of proteases from Bacillus cereus isolates B16, B17, B18, B19 and B20. Isolates were obtained from the University of Baghdad and characterized using several well-accepted biochemical methodologies. Different culture conditions were tested for the production efficiency and specificity of the protease activity. Based on the results of proteolytic activity screening, Bacillus cereus B17 was selected for further analysis. Protease purification was performed with dialysis, ion exchange chromatography and gel filtration chromatography. We have found that the optimum temperature for the production of proteases was 37°C, while the optimum pH level for the protease production was 8.5. In addition, we found that the ideal incubation period for protease production of the isolates was 24 h. Furthermore, we have confirmed that both the temperature and pH affected the protease activity. Importantly, we also found that the metal ions and inhibitors have significant effects on protease activity. In the current study, we have shown that the activity of proteases from Bacillus cereus isolates are significantly affected by incubation period, pH of the growth media and temperature, as well as the presence of metal ions and inhibitors. Keywords: Enzymes, Protease, Bacillus cereus, protease production, protease activity, microorganisms, purification, Enzyme characterization