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Thematic Keynote Lime mortars in heritage: Fundamental insights into carbonation reaction and its biocatalization
Published in Koen Van Balen, Els Verstrynge, Structural Analysis of Historical Constructions: Anamnesis, Diagnosis, Therapy, Controls, 2016
kinetics of conversion of hydrated CO2 into HCO- 3 ions, which is the rate-controlling step of carbonation. Bioinspired approaches can provide a novel solution to master the kinetics of carbonation reaction in lime mortars. Carbonic anhydrase enzyme (CA) is a particularly efficient biocatalyst that takes part in many processes in living organisms such as respiration, CO2 transport and photosynthesis, promoting the hydration of CO2 and the production of HCO- 3 ions (Lindskog 1997). This enzyme plays an important role in microbially-induced calcium carbonate precipitation process. This has inspired many researchers to develop novel biomimetic strategies using CA enzyme as a catalyst CO2 sequestration in industrial applications. CA enzyme belongs to a large group of zinc-based metalloenzymes that are known to catalyse the reversible hydration of carbon dioxide (CO2 + H2 O HCO- + H+ ) (Lindskog 1997). The fastest 3 human CA enzyme (HCA II) can hydrate at least 1.4 × 106 molecules of CO2 per second. At neutral pH and at slightly alkaline pH (ca. 8-9), this enzyme yields enzyme-bound Zn-OH- (reaction 5) that is readily available to react with CO2 (reaction 6). As a result, HCO- ions formation is promoted (reaction 7) and the 3 overall hydration rate of CO2 is enhanced.
Extremophilic Microbes and their Extremozymes for Industry and Allied Sectors
Published in Ajar Nath Yadav, Ali Asghar Rastegari, Neelam Yadav, Microbiomes of Extreme Environments, 2021
Hiran Kanti Santra, Debdulal Banerjee
Inspite of the physical and biological means of planting trees or using chemicals to reduce carbon emissions from popular sources, a great trust is put forward on microbial sources. Microbes from mesophilic or extremophilic origin are able to produce enzymes known as carbonic anhydrase that can cause CO2 breakdown. Carbonic anhydrase is a ubiquitous zinc metalloenzyme (EC No. 4.2.1.1) that mediates the inter-conversion of carbon dioxide to bicarbonates (Smith and Ferry 2000). The process of carbonic anhydrase mediated breakdown of CO2 includes the supply of flue gas on a bioreactor earlier provided with immobilized enzymes set on appropriate beads. Enzymatic action splits CO2 and releases HCO3− and H+ which are used further for several purposes. The selection of microorganisms as a source of carbonic anhydrase is shifted to organisms of extreme environments as they can thrive well in adverse realms of nature. Using thermoalkali stable (can withstand high temperatures and high pH; known as polyextremophile) carbonic anhydrases is an alternative cost effective and highly valued process of mitigating global warming issues. Reports include the presence of all the three necessary genes in prokaryotic organisms; extremophilic archaebacteria and eubacteria (Smith and Ferry 2000). The list of extremophiles as contributors of carbonic anhydrase is listed in Table 1.8. It is a new concept of using extremozymes to solve environmental issues like global warming and hopefully can contribute to open new paths in this respect.
Characterization of marine bacterial carbonic anhydrase and their CO2 sequestration abilities based on a soil microcosm
Published in Preparative Biochemistry & Biotechnology, 2019
Panchami Jaya, Vinod Kumar Nathan, Parvathi Ammini
Tremendous increasing emission of greenhouse gases (GHG) and its deleterious effects on the climate change are the most discussed issue around the globe. Among the various GHGs, carbon dioxide occupies the first position in the anthroposphere and has detrimental effects on the ecosystem.[1] Reducing the levels of atmospheric carbon dioxide and increasing the environmental awareness are the main solution for global warming.[2] Several ongoing researches were started to combat the atmospheric CO2 levels by various methods like CO2 capturing and storage technologies. Among these, one of the promising carbon dioxide sequestrations is by microbial extracellular enzyme, carbonic anhydrase (CA). The biotechnological sequestration of CO2 using CA has more advantages like eco-friendliness and improved rate of catalysis. CA helps the conversion of CO2 into carbonate in an increased reaction rate manifold with the high substrate specificity.[3,4]
Kinetic effect of carbonic anhydrase enzyme on the carbonation reaction of lime mortar
Published in International Journal of Architectural Heritage, 2018
Özlem Cizer, Encarnación Ruiz-Agudo, Carlos Rodriguez-Navarro
Bioinspired approaches can provide a novel solution to master the kinetics of carbonation reaction in lime mortars. In the last decade, precipitation of calcium carbonate in the presence of biological factors (microbial and bovine) such as urease and carbonic anhydrase enzymes has been documented to enhance calcite crystal nucleation and growth (Li et al. 2010; Meldrum 2003; Sondi and Matijevic 2001). The carbonic anhydrase enzyme (CA) is a particularly efficient biocatalyst that takes part in many processes in living organisms such as respiration, CO2 transport and photosynthesis, promoting the hydration of CO2 and the production of HCO3– ions (Lindskog 1997; Smith and Ferry 2000). This enzyme plays an important role in microbially induced calcium carbonate precipitation processes and is known to be the fastest catalyst for carbon dioxide hydration reaction (Achal and Pan. 2011; Khalifah 1971). CA belongs to a large group of zinc-based metalloenzymes that are known to catalyse the reversible hydration of carbon dioxide (CO2 + H2O ↔ HCO3– + H+) without changing the solution chemistry (Lindskog and Coleman 1973; Lindskog 1997). The fastest human CA enzyme (HCA II) can hydrate at least 1.4 x 106 molecules of CO2 per second (Khalifah 1971). Dreybrodt et al. (1996) reported the enhancement of carbon dioxide hydration with 0.6 μM CA enzyme by a factor of 1,500. At neutral pH and at slightly alkaline pH (ca. 8–9), this enzyme yields enzyme-bound Zn-OH– (reaction 6) that is readily available to react with CO2 (reaction 7). As a result, HCO3– ions formation is promoted (reaction 8) and the overall hydration rate of CO2 is enhanced: