title: Identification, characterization, and immobilization of an organic solvent-stable alkaline hydrolase (PA27) from Pseudomonas aeruginosa MH38.
abstract: An organic solvent-stable alkaline hydrolase (PA27) from Pseudomonas aeruginosa MH38 was expressed, characterized, and immobilized for biotechnological applications. Recombinant PA27 was expressed in Escherichia coli as a 27 kDa soluble protein and was purified by standard procedures. PA27 was found to be stable at pH 8-11 and below 50 °C. It maintained more than 80% of its activity under alkaline conditions (pH 8.0-11.0). Furthermore, PA27 exhibited remarkable stability in benzene and n-hexane at concentrations of 30% and 50%. Based on these properties, immobilization of PA27 for biotechnological applications was explored. Scanning electron microscopy revealed a very smooth spherical structure with numerous large pores. Interestingly, immobilized PA27 displayed improved thermal/chemical stabilities and high reusability. Specifically, immobilized PA27 has improved thermal stability, maintaining over 90% of initial activity after 1 h of incubation at 80 °C, whereas free PA27 had only 35% residual activity. Furthermore, immobilized PA27 showed higher residual activity than the free enzyme biocatalysts against detergents, urea, and phenol. Immobilized PA27 could be recycled 20 times with retention of ~60% of its initial activity. Furthermore, macroscopic hydrogel formation of PA27 was also investigated. These characteristics make PA27 a great candidate for an industrial biocatalyst with potential applications.
authors.affiliation: Department of Applied Chemistry and Biological Engineering, College of Engineering, Ajou University, Suwon 443-749, Korea. thomas70kim@gmail.com.
authors.forename: Eunjin
authors.initials: E
authors.lastname: Jang
authors.affiliation: Department of Applied Chemistry and Biological Engineering, College of Engineering, Ajou University, Suwon 443-749, Korea. psryubh@gmail.com.
authors.forename: Bum Han
authors.initials: BH
authors.lastname: Ryu
authors.affiliation: Department of Applied Chemistry and Biological Engineering, College of Engineering, Ajou University, Suwon 443-749, Korea. doohunkim@ajou.ac.kr.
authors.forename: Thomas Doohun
authors.initials: TD
authors.lastname: Kim
mesh_terms: D003001:Cloning, Molecular; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000096:biosynthesis / Q000737:chemistry*; D004926:Escherichia coli; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D009930:Organic Chemicals / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000201:enzymology*; D012997:Solvents / Q000737:chemistry; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D009930:Organic Chemicals; D012997:Solvents; D006867:Hydrolases