title: Utility of thermo-alkali-stable γ-CA from polyextremophilic bacterium Aeribacillus pallidus TSHB1 in biomimetic sequestration of CO2and as a virtual peroxidase.
abstract: Aeribacillus pallidus TSHB1 polyextremophilic bacterium produces a γ-carbonic anhydrase (ApCA), which is a homotrimeric biocatalyst with a subunit molecular mass of 32 ± 2 kDa. The enzyme is stable in the pH range between 8.0 and 11.0 and thus alkali-stable and moderately thermostable with T1/2values of 40 ± 1, 15 ± 1, and 8 ± 0.5 min at 60, 70, and 80 °C, respectively. Activation energy for irreversible inactivation "Ed" of carbonic anhydrase is 67.119 kJ mol-1. The enzyme is stable in the presence of various flue gas contaminants such as SO32-,SO42-, and NO3-and cations Mg2+, Mn2+, Ca2+, and Ba2+. Fluorescence studies in the presence of N-bromosuccinimide and fluorescence quenching using KI and acrylamide revealed the importance of tryptophan residues in maintaining the structural integrity of the enzyme. ApCA is more efficient than the commercially available bovine carbonic anhydrase (BCA) in CO2sequestration. The enzyme was successfully used in biomineralization of CO2from flue gas. Replacement of active site Zn2+with Mn2+enabled ApCA to function as a peroxidase which exhibited alkali-stability and moderate thermostability like ApCA.
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
authors.forename: Himadri
authors.initials: H
authors.lastname: Bose
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. tsnarayana@gmail.com.|Netaji Subhas Institute of Technology, Azad Hind Fauz Marg, Sector 3, Dwarka, New Delhi, 110078, India. tsnarayana@gmail.com.
authors.forename: Tulasi
authors.initials: T
authors.lastname: Satyanarayana
mesh_terms: D000468:Alkalies; D000818:Animals; D032701:Biomimetics; D002245:Carbon Dioxide / Q000737:chemistry; D002417:Cattle; D009195:Peroxidase; D010544:Peroxidases
chemical_list: D000468:Alkalies; D002245:Carbon Dioxide; D010544:Peroxidases; D009195:Peroxidase
keywords: Aeribacillus pallidus TSHB1; Biomineralization; Carbonic anhydrase; Flue gas; Peroxidase; Thermo-alkali-stable