Capturing and storing CO₂ is of prime importance. The rate of CO₂ sequestration is often limited by the hydration of CO₂, which can be greatly accelerated by using carbonic anhydrase (CA, EC 4.2.1.1) as a catalyst. In order to improve the stability and reusability of CA, a silica-condensing peptide (R5) was fused with the fastest known CA from Sulfurihydrogenibium azorense (SazCA) to form R5-SazCA; the fusion protein successfully performed in vitro silicification. The entrapment efficiency reached 100% and the silicified form (R5-SazCA-SP) showed a high activity recovery of 91%. The residual activity of R5-SazCA-SP was two-fold higher than that of the free form when stored at 25 °C for 35 days; R5-SazCA-SP still retained 86% of its activity after 10 cycles of reuse. Comparing with an uncatalyzed reaction, the time required for the onset of CaCO₃ formation was shortened by 43% and 33% with the addition of R5-SazCA and R5-SazCA-SP, respectively. R5-SazCA-SP shows great potential as a robust and efficient biocatalyst for CO₂ sequestration because of its high activity, high stability, and reusability.

Cu₆₀Zr₃₀Ti₁₀ metallic glass powder was prepared by mechanically alloying a mixture of pure Cu, Zr, and Ti powders after 5 h of milling. Cu₆₀Zr₃₀Ti₁₀ bulk metallic glass (BMG) was synthesized by vacuum hot pressing the as-milled Cu₆₀Zr₃₀Ti₁₀ metallic glass powder at 746 K in the pressure range of 0.72–1.20 GPa, and the structure was analyzed through X-ray diffraction and transmission electron microscopy. The pressure could enhance the thermal stability, and prolong the existence, of the amorphous phase inside the Cu₆₀Zr₃₀Ti₁₀ powder. Furthermore, the corrosion behavior of the Cu-based BMG in four corrosive media was studied using a potentiodynamic method. The Cu₆₀Zr₃₀Ti₁₀ BMG exhibited a low corrosion rate and current density in 1 N solutions of H₂SO₄, NaOH, and HNO₃. X-ray photoelectron spectroscopy results revealed that the formation of Zr- and Ti-rich passive oxide layers provides a high corrosion resistance against 1 N H₂SO₄ and HNO₃ solutions, and the breakdown of the protective film by Cl⁻ attack was responsible for pitting corrosion in a 3 wt % NaCl solution. The formation of oxide films and the nucleation and growth of pitting were analyzed through microstructural investigations.

The reaction condition for purifying carbonic anhydrase from Sulfurihydrogenibium yellowstonense (SspCA) by direct heating without prior cell lysis was optimized; heating at 70 °C for 5 min resulted in the highest total activity of 23,460 WAU (Wilbur–Anderson unit) from a 50 mL culture. Heat-purified SspCA was examined for its capability to increase the rate of the mineralization of CO₂; compared with an uncatalyzed control, the onset time of CaCO₃ formation was shortened by up to 71%. Cyanase can be used to degrade toxic cyanate; however, one of the limitations of this biomimetic process is that the reaction needs HCO₃⁻ as a substrate. Heat-purified SspCA was combined with heat-purified cyanase from Thermomyces lanuginosus to alleviate the HCO₃⁻ dependence; in industrial wastewater, the HCO₃⁻ required was reduced by 50% when 0.75 WAU of SspCA was added. Heat-purified SspCA is stable at 4 °C; 88% of the initial activity was retained for up to five weeks. Partially purified SspCA can be obtained with ease and applied to a variety of applications.

Carbonic anhydrase (CA), an enzyme that accelerates CO₂ hydration, is one of the most widely used enzymes in the aid of CO₂ sequestration. We entrapped CA from Sulfurihydrogenibium azorense (SazCA) within biomimetic silica; to enhance the activity of the entrapped enzyme, the microenvironment of the silica particles was modified by using methyltrimethoxysilane (MTMS) or dimethyldimethoxysilane (DMDMS) as part of the precursors. When 10% (mol/mol) MTMS or 20% DMDMS was added to tetramethoxysilane (TMOS), the activity of entrapped SazCA increased by almost threefold when compared with the control group without these methyl-substituted silanes. In addition, all three types of entrapped SazCA, namely, the silica formed with only TMOS, 10% MTMS in TMOS, and 20% DMDMS in TMOS, exhibited improved thermal stability and pH stability. All three types of entrapped SazCA also showed good storage stability, with at least 79% of their initial activities retained after being stored at room temperature for six weeks, while the activity of the free enzyme dropped to 14% after only two days. When all three types of entrapped SazCA were applied to carbon sequestration, the efficiency remained above 90% even after ten cycles of reuse.