title: High expression and biosilica encapsulation of alkaline-active carbonic anhydrase for CO2 sequestration system development.
abstract: Carbonic anhydrase (CA) is a biocatalyst for CO2 sequestration because of its distinctive ability to accelerate CO2 hydration. High production and efficient immobilization of alkaline-active CAs are required, because one potential application of CA is its use in the alkaline solvent-based CO2 absorption/desorption process. Here, we designed and applied an α-type CA from Hahella chejuensis (HCA), which was reported as highly active in alkaline conditions, but was mostly expressed as insoluble forms. We found that the signal peptide-removed form of HCA [HCA(SP-)] was successfully expressed in the soluble form [∼70mg of purified HCA(SP-) per L of culture]. HCA(SP-) also displayed high pH stability in alkaline conditions, with maximal activity at pH 10; at this pH, ∼90% activity was maintained for 2h. Then, we prepared HCA(SP-)-encapsulated silica particles [HCA(SP-)@silica] via a spermine-mediated bio-inspired silicification method. HCA(SP-)@silica exhibited high-loading and highly stable CA activity. In addition, HCA(SP-)@silica retained more than 90% of the CA activity even after 10 cycles of use in mild conditions, and ∼80% in pH 10 conditions. These results will be useful for the development of practical CO2 sequestration processes employing CA.
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
authors.forename: Ki-Ha
authors.initials: KH
authors.lastname: Min
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
authors.forename: Ryeo Gang
authors.initials: RG
authors.lastname: Son
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea.
authors.forename: Mi-Ran
authors.initials: MR
authors.lastname: Ki
authors.affiliation: Department of Chemical Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea. Electronic address: biochoi@cnu.ac.kr.
authors.forename: Yoo Seong
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea. Electronic address: spack@korea.ac.kr.
authors.forename: Seung Pil
authors.initials: SP
authors.lastname: Pack
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002256:Carbonic Anhydrases / Q000737:chemistry*; D004926:Escherichia coli; D004950:Esterases / Q000737:chemistry; D020563:Gammaproteobacteria / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D012997:Solvents; D013096:Spermine / Q000737:chemistry; D013696:Temperature
chemical_list: D012997:Solvents; D002245:Carbon Dioxide; D013096:Spermine; D012822:Silicon Dioxide; D004950:Esterases; D002256:Carbonic Anhydrases
keywords: Bio-inspired silicification; Biosilica encapsulation; CO(2) sequestration; Carbonic anhydrase; Hahella chejuensis; Immobilization