Stability Of Ca Research Articles

Experimental determination of calcite solubility and the stability of aqueous Ca– and Na–carbonate and –bicarbonate complexes at 100–160 °C and 1–50 bar pCO2 using in situ pH measurements

The solubility of calcite was measured at 100, 120, 140 and 160 °C at 1–50 bar pCO2 in 10−3–0.1 mol·kg−1 NaCl solutions using a new experimental setup involving in situ pH measurements with high-temperature solid-contact H-selective glass and two types of reference electrodes: (i) Ag/AgCl in 3.5 M KCl, saturated AgCl placed in a Teflon extensible container with liquid junction, and (ii) solid-contact high-T Na-selective glass electrode in the cell without liquid junction. The stability constants of NaHCO3° and NaCO3− aqueous complexes formation were determined in NaCl-Na2CO3/NaHCO3 solutions in CO2-free media and under 10 bar pCO2 from 100 to 160 °C. These values allowed calculation of the pH of the calibration solution in the system NaCl-CO2-H2O used in the cell without liquid junction with Na+-selective electrode as a reference. This highly stable, low-cost electrode system can be recommended for routine pH measurements at 4 < pH < 10 in sodium-bearing solutions up to 160 °C and the critical point of CO2. The values of the stability constants of CaCO3° and CaHCO3+ aqueous complexes and calcite solubility product were generated at 100, 120, 140 and 160 °C allowing a description of the solubility of calcite in a wide range of pH and pCO2.

Three Major Phosphoacceptor Sites in HIV-1 Capsid Protein Enhances its Structural Stability and Resistance Against the Inhibitor: Explication Through Molecular Dynamics Simulation, Molecular Docking and DFT Analysis.

Human Immunodeficiency Virus 1 (HIV-1) is a lentivirus, which causes various HIV-associated infections. The HIV-1 core dissociation is essential for viral cDNA synthesis and phosphorylation of HIV-1 capsid protein (HIV-1 CA) plays an important role in it. The aim of this study was to explicate the role of three phosphoserine sites i.e. Ser109, Ser149 and Ser178 in the structural stability of HIV-1 CA, and it's binding with GS-CA1, a novel potent inhibitor. Eight complexes were analyzed and Molecular Dynamics (MD) simulations were performed to observe the stability of HIV-1 CA in the presence and absence of phosphorylation of serine residues at four different temperatures i.e. 300K, 325K, 340K and 350K, along with molecular docking and DFT analysis. The structures showed maximum stability in the presence of phosphorylated serine residue. However, GS-CA1 docked most strongly with the native structure of HIV-1 CA i.e. binding affinity was -8.5 kcal/mol (Ki = 0.579 µM). These results suggest that the phosphorylation of these three serine residues weakens the binding of GS-CA1 with CA and casts derogatory effect on inhibition potential of this inhibitor, but it supports the stability of HIV-1 CA structure that can enhance regulation and replication of HIV-1 in host cells.

Native ion mobility mass spectrometry reveals that small organic acid fragments impart gas-phase stability to carbonic anhydrase II.

A key element of studies that utilise ion mobility mass spectrometry (IM-MS) under native electrospray conditions for the analysis of protein-ligand binding is the maintenance of the native conformation of a protein during the removal of bulk solvent. Ruotolo and co-workers have demonstrated that the binding and subsequent dissociation of the anionic component of inorganic salts stabilise native protein conformations in the gas phase. In this study, we investigated the effect that organic acid fragments identified from a fragment-based drug discovery (FBDD) campaign might have on the gas-phase stability of carbonic anhydrase II (CA II). We utilised native IM-MS to monitor changes in the conformation of CA II in the absence and presence of four acidic fragments. By performing a series of collision-induced unfolding (CIU) experiments we determined the effect of fragment binding on the gas-phase stability of CA II. Binding and dissociation of acidic fragments result in increased gas-phase stability of CA II. CFU experiments revealed that the native-like compact gas-phase conformation of the protein is stable with higher degree of pre-activation when bound to a series of acidic fragments. Importantly, although acetate was present in high concentrations, the stabilising effect was not observed without the addition of the acidic fragments. Binding and subsequent dissociation of acidic fragments from CA II significantly delayed CIU in a manner which is probably analogous to the effect of inorganic anions. Furthermore, we saw a slightly altered stabilising effect between the different fragments investigated in this study. This suggests that the prevention of CIU by organic acids may be tuneable to specific properties of a bound ligand. These observations may open avenues to exploit IM-MS as a screening platform in FBDD.

Chemical stability of Ca3Co4-x O9+δ /CaMnO3-δ p-n junction for oxide-based thermoelectric generators.

An all-oxide thermoelectric generator for high-temperature operation depends on a low electrical resistance of the direct p–n junction. Ca3Co4−xO9+δ and CaMnO3−δ exhibit p-type and n-type electronic conductivity, respectively, and the interface between these compounds is the material system investigated here. The effect of heat treatment (at 900 °C for 10 h in air) on the phase and element distribution within this p–n junction was characterized using advanced transmission electron microscopy combined with X-ray diffraction. The heat treatment resulted in counter diffusion of Ca, Mn and Co cations across the junction, and subsequent formation of a Ca3Co1+yMn1−yO6 interlayer, in addition to precipitation of Co-oxide, and accompanying diffusion and redistribution of Ca across the junction. The Co/Mn ratio in Ca3Co1+yMn1−yO6 varies and is close to 1 (y = 0) at the Ca3Co1+yMn1−yO6–CaMnO3−δ boundary. The existence of a wide homogeneity range of 0 ≤ y ≤ 1 for Ca3Co1+yMn1−yO6 is corroborated with density functional theory (DFT) calculations showing a small negative mixing energy in the whole range.

Dichlorination in a circulating fluidized-bed incinerator for municipal solid waste incineration system

Cl is one of the main pollutants emitted from domestic waste incineration systems. In this study, we focused on the process of Ca dechlorination in the furnace of a circulating fluidized-bed waste incineration system. We analyzed the stability of CaCl2 and Ca in the furnace, the dechlorination process, and distribution of Cl in the incineration system. The results show that the optimal Ca/Cl molar ratio for Ca dechlorination in the circulating fluidized-bed waste incinerator is 2:1; moreover, the dechlorination product CaCl2 was found to decompose at high temperatures (> 850 °C). At temperatures > 700 °C, we measured CaCl2 decomposition rates up to 80%. Ca was added in the furnace, mainly to provide a dechlorination Ca source for the decomposition of limestone into tail flue gas. The amount of Ca2+ in the flue decreased gradually, parallelly to the temperature of the flue gas. Stable CaCl2 was formed after HCl was captured, and relatively small solid particles appeared in the ash collecting bag.

Circular utilization of Co(II) adsorbed composites for efficient organic pollutants degradation by transforming into Co/N-doped carbonaceous catalyst

Abstract Resource recovery and environmental remediation serve to meet the scientific and technical challenges of cost-effective and sustainable strategy, especially for circular utilization of valuable metal and treatment of various wastewater (toxic metal ions, organics, etc.). Encouragingly, the research on circular utilization of recovered valuable metals in peroxymonosulfate (PMS) activation for pollutants degradation is currently in blank; herein, a multistage utilization process for preparing Co/N-doped carbonaceous catalyst is plausibly proposed for the first time. Namely, by using a cheap and abundant alginate as a self-generating 3D network precursor, the interior/exterior modified aerogel beads (denoted as Ca–Me/SA@0.75PEI) are fabricated via a simple sol-gel assembly for toxic metals removal or valuable metals recovery, following that Co2+ adsorbed composite (denoted as Ca–Me/SA@0.75PEI-Co) are converted into Co/N-doped carbonaceous catalyst (denoted as Ca-NC@0.75PEI-Co-700) by carbonization. Increased surface chelating sites and polarity with abundant functional components (N = 15.68%) bring strong affinity to metal ions via ion-exchange, complexation and electrostatic interactions. Detailed isotherms, kinetics and dynamic studies illuminate the high adsorption capacity (698.62 mg/g), fast adsorption rate and long-term operation stability of Ca–Me/SA@0.75PEI adsorbent toward Co2+, respectively. Of particular interest of is that, the catalyst evolved from Co2+ adsorbed composite exhibits relatively-superior catalytic ability towards utilizing PMS oxidant to degrade organic pollutants. Animatingly, the simulation of real water system makes it potential for the multistage utilization of composites in actual industrial wastewater treatment. The coupling of watermelon-like structure and Co/N co-doping endows the adsorptive catalyst sustainable utilization capacity in heterogeneous catalysis based on the concept of “utilizing waste treating waste” circular economy, avoiding the problem of insufficient stability of ion adsorbed aerogel catalyst in PMS homogeneous catalysis.

Decoupling of nutrient cycles in a Eucalyptus woodland under elevated CO2

Abstract Elevated atmospheric [CO2] (eCO2) is currently altering nutrient cycling and availability in ecosystems worldwide. If the availabilities and turnover rates of macro‐ and micronutrients are differentially affected, then nutrient cycles may become out of sync (i.e., decoupled). We evaluated the impacts of 3 years of eCO2 (550 µmol CO2/mol) on the availability, stability and coupling of eleven essential macro and micronutrients in a mature, P‐limited Eucalyptus woodland from Eastern Australia (EucFACE). Despite increases in N and P availability in the first 18 months of study, nutrient availabilities and their stoichiometric ratios were unaffected by eCO2 across the study period (26–57 months of experimental duration). In contrast, the stability of nutrient availability increased under eCO2, which was concomitant with a reduction in the degree of biogeochemical coupling. Synthesis. We demonstrate that macro‐ and micro‐nutrient cycles can quickly become out of sync (i.e., decoupled) under eCO2 in a low‐nutrient Australian eucalypt woodland, despite the lack of consistent effects on nutrient availability; such decoupling of nutrient cycles may have unpredicted consequences in terms of ecosystem functioning under the widely assumed positive relationship between biogeochemical coupling and ecosystem functioning.

Immobilization of carbonic anhydrase on polyethylenimine/dopamine codeposited membranes

ABSTRACTCarbonic anhydrase (CA) catalyzing CO2 hydration has an important application in carbon capture, and its immobilization is very significant. Here, CA was covalently linked by glutaraldehyde (GA) to the surface of poly(vinylidene fluoride) (PVDF) and polyethylene (PE) membranes, which were previously modified via a simple codeposition of polyethyleneimine (PEI) and dopamine (DA). The effects of the modification conditions were investigated, and the membranes were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The immobilization process was optimized, and the catalytic properties of immobilized CA were studied. The results show that the optimal mass ratio of PEI and DA was 1:1 and the deposition time was 10–12 h, at which the surface amino group density could reach 1.278 × 10−7 and 1.397 × 10−7 mol/cm2 for PVDF and PE, respectively. For enzyme immobilization, the optimal CA and GA concentrations were 0.2 mg/mL and 0.1 wt %, and a maximum activity recovery of about 53% and 76% could be achieved for PVDF‐attached CA and PE‐attached CA, respectively. Their Km values were 10.62 mM and 8.6 mM, and the corresponding Kcat/Km values were 132.2 M−1 s−1 and 312.9 M−1 s−1. After immobilization, the storage stability and reusability of CA were much improved. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47784.

METHODOLOGY OF FORMING THE SYSTEM OF ENSURING FINANCIAL STABILITY OF CREDIT INSTITUTIONS

This paper is devoted to the research of methodological foundations for ensuring financial stability system of credit institutions. The ensuring credit institutions’ financial stability should be based on the value-oriented, risk-oriented approaches and, above all, on the systemic approach. The formation of a system of ensuring financial stability of credit institutions can’t be set only by the organizational and managerial influence on the unbalancing resources of the credit institutions, but also foresee an arrangement of an appropriate informal institutional environment that would serve as a world-view platform for successful implementation of measures on financial stability.Original results. It’s determined the nature of the system of ensuring financial stability of credit institutions, the goals and targets of its functioning, object and subject composition, internal structure and scientific principles that determine its nature and peculiarities of its interaction with the external environment. The main components of the studied system include: informal institutional environment; formal institutional environment; the methodical (cognitive) and supplying subsystems. The informal institutional environment is one. Its quality influence on the effectiveness of measures to ensure the financial stability of credit institutions and the ability to maintain it in a long-term period.Practical relevance. The functionality of the proposed system largely depends on the quality of corporate ethics and the depth of its implementation in the activities of credit institutions. Thus, fraudulent actions, provoked by a business entity (a credit institution), including intentional actions to create a crisis situation in the institution, cannot be turned away by the system. The proposed system is only capable of managing the real threats to financial stability, namely those caused by objective internal or external factors.

Cellulose acetate/AgNPs-organoclay and/or thymol nano-biocomposite films with combined antimicrobial/antioxidant properties for active food packaging use

Nano-biocomposite films based on plasticized cellulose acetate/triethyl citrate (CA/TEC) were prepared with silver nanoparticles (AgNPs)/gelatin-modified montmorillonite nanofiller (AgM) and thymol (Th). AgNPs were biosynthesized in situ the clay using Curcuma longa (C. longa) tuber extract. Full characterization of clay and the formulated films was conducted including morphological, physical and functional properties. From the results, the AgNPs showed spherical shape, face centred cubic crystalline structure, and small average size with narrow distribution. Intercalated structure of films was achieved with some exfoliated platelets and clay aggregates. The glass transition temperature (Tg) of CA increased slightly by the added clay but decreased by Th due to its plasticizing effect. Also, the thermal stability of CA was enhanced only by the added clay. Increasing contents of both additives into films declined the optical clarity but enhanced greatly the UV barrier ability. The clay improved the tensile and oxygen barrier properties, while the Th initiated an antagonist effect. Besides, the radical 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) tests highlighted antioxidant activities of Th-included films. The films showed antimicrobial activities against bacteria and fungi, where Escherichia coli (E. coli) was the most sensitive, with an efficient growth inhibition in vapour-phase method. These materials with antimicrobial/antioxidant properties are promising active packaging.

Heterogeneously catalyzed transesterification of palm oil with methanol to produce biodiesel over calcined dolomite: The role of magnesium oxide

Calcined dolomite, composed of calcium oxide (CaO) and magnesium oxide (MgO), is a potential solid base catalyst for the transesterification of triglycerides with methanol to produce biodiesel. However, the catalytic role of MgO in the calcined dolomite is not well understood. We studied the effect of calcination conditions on the formation of the metal oxide phases and the catalytic activity of the resulting dolomite-derived mixed metal compounds. Natural calcite with an analogous trigonal-rhombohedral crystal was used for comparison. The surface basicity of the calcined materials was dependent on the type and cluster size of the oxides, which were controlled by varying calcination temperature and heating rate, while their catalytic activity was principally determined by the bulk CaO content. X-ray photoelectron spectroscopy indicated the growth of MgO on the calcined dolomite, which possessed an oxygen-deficient surface. The generated MgO exhibited a low basicity, low reactivity with methanol and glycerol in phase transformation, and low transesterification catalytic activity under the studied conditions. The oxide materials obtained from the calcite and dolomite calcined at 800 °C exhibited the highest basicity and catalytic activity, giving the FAME yield of >99 wt% under the studied conditions. The CaO nanocrystallites obtained from the dolomite were highly accessible and more reactive than those derived from calcite in the methoxide formation. An in situ formation of calcium hydroxide (Ca(OH)2) was observed for the oxide materials directly reacted with methanol or glycerol and those spent in the transesterification. The small crystallites of dolomite-derived mixed oxides maintained the structural stability of Ca(OH)2 as an active phase, resulting in a lower formation of bulk glyceroxides.

Thermal cycling stability of thermochemical energy storage system Ca(OH)2/CaO

Thermochemical energy storage (TCS) stores and releases heat through a reversible chemical reaction. And since thermochemical material (TCM) is the most important part of an energy storage system, its properties directly affect the entire system. On account of a variety of advantages such as low cost, broad availability and suitable temperature range, thermochemical method based on reversible decomposition reaction has become a famous research. In this study, a TCS experimental setup was built to investigate thermal cycling stability of the Ca(OH)2/CaO system. Through successive 20 dehydration-hydration cycles, amount of stored thermal capacity and cyclic reversibility of the Ca(OH)2/CaO system are analyzed. After research and analysis, existing problems of the Ca(OH)2/CaO energy storage system including agglomeration and sintering, poor thermal conductivity, unevenness of heat release rate are concluded and raised. After an explanation of superior performance and existing problems occurred during the dehydration and hydration process, this research lays the foundation of applying the Ca(OH)2/CaO system to practical.

Metal Borohydrides as Electrolytes for Solid-State Li, Na, Mg, and Ca Batteries: A First-Principles Study

Metal borohydrides are a family of materials that were recently discovered to have extraordinary ionic conductivities, making them promising candidates as electrolytes for solid-state batteries (SSBs). In fact, various groups have measured the ionic conductivities and assembled batteries using specific borohydrides. However, there are no comprehensive studies assessing the thermodynamic properties or discussing the suitability of metal borohydrides as electrolytes in SSBs, especially for beyond-lithium applications. In this work, we investigate the electrochemical stability, interfacial characteristics, mechanical properties, and ionic conductivities of Li, Na, Ca, and Mg borohydrides using first-principles calculations. Our results suggest that Li and Na borohydrides are unstable at high voltages. However, the corresponding decomposition products, i.e., B12H122–-containing phases, have wide electrochemical windows which protect the electrolyte, leading to large electrochemical windows as wide as 5 V. In ...

A Ca and Fe Co-Doped Layered Perovskite as Stable Air Electrode in Solid Oxide Electrolyzer Cells under High-Current Electrolysis

In this study, the electrochemical performance and the stability of Ca and Fe co-doped SmBaCo2O5+δ, SmBa0.75Ca0.25CoFeO5+δ (SBCCF), layered perovskite is examined as the air electrode for solid oxide electrolyzer cells (SOECs). In a half-cell with three-electrode configuration, the initial polarization resistance, RP, of GDC|SBCCF is 0.16Ωcm2 at 800°C. Under an anodic bias of 200mV, RP decreases to 0.03Ωcm2 ; however, under cathodic bias of 200mV, RP increases to 0.18Ωcm2, indicating that SBCCF is more active towards oxygen evolution reaction than oxygen reduction reaction. During the electrolysis test under 1Acm−2 at 800°C for 216h, RP of GDC|SBCCF increases to 0.52Ωcm2 in the first 96h and remains at 0.52Ωcm2 for the remaining 120h. In contrast, RP of GDC|LSCF increases with a rate of 0.08Ωcm2/100h at the same time. This result demonstrates that SBCCF is a promising candidate as air electrode in SOECs for stable operation under high electrolysis current, which is critical to achieve high hydrogen production rate and to lower the cost of the system. Effective methods for the improvement of the performance of SBCCF will be developed in future studies.

Structural Stability Among Hybrid Antimicrobial Peptide Cecropin A(1–8)–Magainin 2(1–12) and Its Analogues: A Computational Approach

Cecropin A–Magainin 2 (CA–MA) hybrid antimicrobial peptide (AMP), a combination of two naturally occurring AMPs, cecropin A and magainin 2 is preferred widely in biotechnological, nano and pharmaceutical applications. It exhibits a strong antibacterial activity with a characteristic reduced cytotoxic effect towards mammalian cells. In this study, three AMP structures native CA–MA hybrid and its tryptophan substitutes CA–MA L2 and CA–MA A2 was computationally studied to analyze their structural stability and functionality. Computational analysis like, intra-molecular interactions (25), relative stability (3.22) and instability index (−14.28) showed an increase in structural stability of native CA–MA hybrid. Additionally, the generated peptide ensembles showed a RMSD (3.98 A), RMSF (0.202 A), radius of gyration (11.98 A), ovality (3.33) and hydrophobicity (69.7%) supporting native CA–MA along with hydrogen bond strength (−4.212 kcal/mol) and distribution comparatively. The distribution of secondary structure in native CA–MA hybrid showed the sequential maintenance of stable helical content along with helical stability (52.25%) and computed free energy (−1.74 kcal/mol) in membrane mimicking environment proving its functional activity comparatively. This study aids in designing stable AMP biodrugs with low cytotoxicity in future, the result can be potentially extended to other AMPs to assist in their exploitation as peptide and nano drugs.

Structural stability and thermoelectric property optimization of Ca2Si

By using an ab initio evolutionary algorithm structure search, low enthalpy criterion as well as stability analysis, we have found that cubic Fm3̄m Ca2Si can be achieved under a negative external pressure.

Preparation of antibacterial chlorhexidine/vermiculite and release study

The antibacterial chlorhexidine/vermiculite (CA/Ver) was successfully prepared through the intercalation process and the stability of CA on the vermiculite matrix and was investigated by stirring in aqueous solutions under the influence of different pH and temperature. The content of CA was determined by total organic carbon (TOC) analysis before and after stability tests. The structure of all samples was characterized by X-ray powder diffraction (XRD) and Fourier–transform infrared spectroscopy (FTIR). The antibacterial activity of prepared CA/Ver samples was evaluated by finding a minimum inhibitory concentration (MIC) against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The content of chlorhexidine ranged from 209 to 231.6mg of CA in 1g of the whole sample after the intercalation process. After stability study, only a slight outflow of CA from the Ver matrix (<5%) was noted. The antibacterial test confirmed that the outflow of CA was negligible.After 30min of exposition the MIC of organovermiculite samples before and after stability test were the same for Staphylococcus aureus and Escherichia coli with value 3.33 (%; w/v) and the MIC decreased to 0.014 (%; w/v) with longer time of exposition (120h). A small difference was observed at Enterococcus faecalis where MIC was 10 (%; w/v) after 30min of exposition for the sample after stability test in neutral pH. However, after 24h of treatment the MIC value decreased to 0.014 (%; w/v). And finally, bacterial strain Pseudomonas aeruginosa showed a great resistance against antibacterial organovermiculite samples and MIC did not decreased under 10 (%; w/v) even after 5days of exposition.

Improved structure stability, optical and magnetic properties of Ca and Ti co-substituted BiFeO3 nanoparticles

We report the optical and magnetic properties of single-crystalline Ca and Ti co-substituted bismuth ferrite, Bi1-xCaxFe1-xTixO3, nanoparticles, synthesized by a facile sol–gel methodology in the compositional range wherein 0≤x≤0.25. X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations show that all samples possess a rhombohedrally distorted perovskite structure with space group R3c. Ca and Ti co-substitution controls the formation of secondary phases and improved the stability of perovskite phase of BiFeO3. The average particle size was estimated by Williamson Hall plot, confirmed by TEM, and found to be about 59, 50, 46, 41, 40 and 38nm of Bi1-xCaxFe1-xTixO3 for x=0, 0.05, 0.10, 0.15, 0.20 and 0.25, respectively. The UV–vis absorption study reveal the strong absorption of visible light with a small optical band gap (1.77–2.25eV) for 0≤x≤0.25 indicates a possibility of utilizing for photocatalytic activities. The magnetic study at room-temperature displays the improved magnetization and coercive field in Bi1-xCaxFe1-xTixO3 nanoparticles due to the release of the latent magnetization locked within the toroidal spin structure of BiFeO3.

Investigation on thermal properties of capric–palmitic–stearic acid/activated carbon composite phase change materials for high-temperature cooling application

Based on the theory calculation, the capric–palmitic–stearic (CA–PA–SA) ternary eutectic mixture was prepared with melting and freezing temperature of 19.93 and 16.84 °C, respectively. Regarding CA–PA–SA as phase change materials (PCMs), and activated carbon (AC) as the additive, the CA–PA–SA/AC composites can be prepared by physical blend method which can be applied to high-temperature cooling application in solar cooling systems, radiant cooling systems, etc. A comprehensive study of the structure, thermal properties, thermal stability, thermal durability and thermal storage-release characteristic of CA–PA–SA/AC composites was conducted through the FT-IR, DSC, TG, accelerated thermal cycling test and melting–freezing experiments. The results show that, with the increase in AC content, the melting temperature of CA–PA–SA/AC composites decreases gradually, whereas the freezing temperature increases. And the addition of AC can enhance the thermal stability, the thermal durability and the thermal storage-release rate of PCM: the thermal stability of PCM1–PCM4 is much greater than that of pure mixture, and its storage time was reduced by 37, 31, 23 and 9 %, respectively, while its release time was reduced by 67, 58, 48 and 43 % respectively.

Identification of a new thermostable and alkali-tolerant α-carbonic anhydrase from Lactobacillus delbrueckii as a biocatalyst for CO2 biomineralization

Carbonic anhydrase (CA, EC 4.2.1.1), an ancient enzyme and the fastest among many enzymes, is a useful biocatalyst for carbon capture use and storage (CCUS). The use of alkaline buffers and high temperatures are favorable for biomineralization. Hence, the stability of CA under such harsh conditions is extremely important for its practical application. Herein, we report a new thermostable and alkaline-tolerant α-CA (designated as LdCA), with only 26 % identity to bovine CA (BCA), which was identified by genome mining from Lactobacillus delbrueckii CGMCC 8137. It was overexpressed in Escherichia coli in a soluble form and purified to electrophoretic homogeneity by His-Trap affinity chromatography. The dimer protein had a subunit molecular weight of 23.8 kDa and showed extremely high stability at pH 6.0–11.0 and 30–60 °C. Its activity was maintained even after incubation at 90 °C for 15 min. The half-lives of the enzyme measured at 30, 40, and 50 °C were 630, 370, and 177 h, respectively. At pH 9.0, 10.0, and 11.0, its half-lives were 105, 65, and 41 min, respectively. LdCA was applied at 50 °C to accelerate the formation of calcium carbonate in a vaterite phase. In summary, a new CA with high thermal and alkaline stability was identified from a general bacterium, demonstrating an effective strategy for discovering new and useful biocatalysts.