Accelerated CO2 Hydration with Thermostable Sulfurihydrogenibium azorense Carbonic Anhydrase-Chitin Binding Domain Fusion Protein Immobilised on Chitin Support

Abstract

Carbonic anhydrases (CAs) represent a group of enzymes that catalyse important reactions of carbon dioxide hydration and dehydration, a reaction crucial to many biological processes and environmental biotechnology. In this study we successfully constructed a thermostable fusion enzyme composed of the Sulfurihydrogenibium azorense carbonic anhydrase (Saz_CA), the fastest CA discovered to date, and the chitin binding domain (ChBD) of chitinase from Bacillus circulans. Introduction of ChBD to the Saz_CA had no major impact on the effect of ions or inhibitors on the enzymatic activity. The fusion protein exhibited no negative effects up to 60 °C, whilst the fusion partner appears to protect the enzyme from negative effects of magnesium. The prepared biocatalyst appears to be thermally activated at 60 °C and could be partially purified with heat treatment. Immobilisation attempts on different kinds of chitin-based support results have shown that the fusion enzyme preferentially binds to a cheap, untreated chitin with a large crystallinity index over more processed forms of chitin. It suggests significant potential economic benefits for large-scale deployment of immobilised CA technologies such as CO2 utilisation or mineralisation.

Enzymatic Modifications of Chitin, Chitosan, and Chitooligosaccharides

“…Furthermore, complexes formed with higher molecular weight chitosan are more stable and demonstrate higher transfection efficiency (Bordi et al, 2014). In addition to the indicated examples of chitosan applications, this biopolymer has been used in many other industries, e.g., as adsorbents for dye removal from water and wastewater (Vakili et al, 2014), as ingredients of cosmetic that increases the water-resistance of emulsions protecting against sun irradiation and consequently enhances its film-forming ability (Aranaz et al, 2018), as a food ingredient (Shahidi et al, 1999), as a carrier for enzyme immobilization (Biró et al, 2008; Hou et al, 2019).…”

“…Substantial improvement in the cost-effectiveness of enzymatic processes can be obtained by the assembly of numerous enzymes and co-enzymes in vitro in so-called cascade biocatalysis (You et al, 2012; Liu et al, 2013). Expression of fusion proteins with multifunctional activity can also significantly reduce the cost of enzymatic methods (Iturrate et al, 2009) and provide desirable binding properties toward the chitin (Hou et al, 2019). However, it is sometimes challenging to obtain multifunctional proteins that keep the activity and substrate specify of native enzymes.…”

Debottlenecking Thermophilic Cyanobacteria Cultivation and Harvesting through the Application of Inner-Light Photobioreactor and Chitosan

“…This suggests that in the case of thermophilic cyanobacteria, utilisation of air as a carbon dioxide source is suboptimal and is likely to result in carbon limitation. Cyanobacteria uptake different carbon species using different mechanisms; CO 2 is typically taken up passively and transformed into bicarbonate inside the cell by carbonic anhydrase, an enzyme that maintains the balance between intracellular inorganic carbon species [ 26 ]. The alternative route for CO 2 entry is directly through a bicarbonate ion HCO 3 - .…”

QM study of carbon dioxide (CO2) and carbonyl sulfide (COS) degradation by cluster model of Carbonic anhydrase enzyme

“…Carbonic anhydrases (CAs, EC 4.2.1.1) enzymes belong to one of the most interesting superfamily of metalloenzymes which catalyze the hydration of carbon dioxide (CO 2 ) to bicarbonate ion and proton, a simple but essential reaction [1][2][3][4][5][6][7]. This enzyme (CA) is present in most living organisms including prokaryotes and eukaryotes and encoded to five classes: α-CAs, β-CAs, γ-CAs, δ-CAs and ζ-CAs [8][9][10][11][12].…”