The production and biochemical characterization of α-carbonic anhydrase from Lactobacillus rhamnosus GG

Inhibition of Pseudomonas aeruginosa Carbonic Anhydrases, Exploring Ciprofloxacin Functionalization Toward New Antibacterial Agents: An In-Depth Multidisciplinary Study

Ciprofloxacin (CPX) is one of the most employed antibiotics in clinics to date. However, the rise of drug-resistant bacteria is dramatically impairing its efficacy, especially against life-threatening pathogens, such as Pseudomonas aeruginosa. This Gram-negative bacterium is an opportunistic pathogen, often infecting immuno-compromised patients with severe or fatal outcomes. The evidence of the possibility of exploiting Carbonic Anhydrase (CA, EC: 4.2.1.1) enzymes as pharmacological targets along with their role in P. aeruginosa virulence inspired the derivatization of CPX with peculiar CA-inhibiting chemotypes. Thus, a large library of CPX derivatives was synthesized and tested on a panel of bacterial CAs and human isoenzymes I and II. Selected derivatives were evaluated for antibacterial activity, revealing bactericidal and antibiofilm properties for some compounds. Importantly, promising preliminary absorption, distribution, metabolism, and excretion (ADME) properties in vitro were found and no cytotoxicity was detected for some representative compounds when tested in Galleria mellonella larvae.

Isolation, Identification, and Carbonate Mineralization Characteristics of a Newly Carbonic Anhydrase-Producing Strain

Carbonic anhydrase-producing microorganisms can rely on their metabolism for carbon sequestration and carbonate precipitation, which is a relatively effective mode among the known microbially induced carbonate precipitation (MICP) methods. A newly carbonic anhydrase-producing strain was isolated from soil samples. 16S rDNA gene sequencing showed this strain had 99.18% sequence identity to Chryseobacterium gambrini. Various culture parameters (temperature, pH, rotational speed, inoculum size, and metal ions) were optimized for optimal microbial growth and CA activities. Optimal culture conditions were as follows: temperature of 30 °C, pH 6-7, rotational speed 150 rpm, and inoculum size 1%. It was observed that Co2+ and Mn2+ can improve CA activity with optimal concentrations of 0.02 mM and 0.01 mM, respectively. Furthermore, the introduction of CO2 for 15 min daily leads to a 36% increase in the final production of biotic CaCO3, reaching 2.884 g/L. Characterization of the mineralization precipitates was conducted to reveal the mechanism of the carbonic anhydrase-producing bacterium. Lastly, an analysis of the crystalline species and content of the biogenic CaCO3 was performed to lay the groundwork for future crystalline adjustments and to offer technical support for the application of the calcium method.

Bacterial α-CAs: a biochemical and structural overview

Carbonic anhydrases belonging to the α-class are widely distributed in bacterial species. These enzymes have been isolated from bacteria with completely different characteristics including both Gram-negative and Gram-positive strains. α-CAs show a considerable similarity when comparing the biochemical, kinetic and structural features, with only small differences which reflect the diverse role these enzymes play in Nature. In this chapter, we provide a comprehensive overview on bacterial α-CA data, with a highlight to their potential biomedical and biotechnological applications.

Characteristics of cold-adapted carbonic anhydrase and efficient carbon dioxide capture based on cell surface display technology

Carbonic anhydrase (CA) is currently under investigation because of its potential to capture CO2. A novel N-domain of ice nucleoproteins (INPN)-mediated surface display technique was developed to produce CA with low-temperature capture CO2 based on the mining and characterization of Colwellia sp. CA (CsCA) with cold-adapted enzyme structural features and catalytic properties. CsCA and INPN were effectively integrated into the outer membrane of the cell as fusion proteins. Throughout the display process, the integrity of the membrane of engineered bacteria BL21/INPN-CsCA was maintained. Notably, the study affirmed positive applicability, wherein 94 % activity persisted after 5 d at 15 °C, and 73 % of the activity was regained after 5 cycles of CO2 capture. BL21/INPN-CsCA displayed a high CO2 capture capacity of 52 mg of CaCO3/mg of whole-cell biocatalysts during CO2 mineralization at 25 °C. Therefore, the CsCA functional cell surface display technology could contribute significantly to environmentally friendly CO2 capture.

A simple yet multifaceted 90 years old, evergreen enzyme: Carbonic anhydrase, its inhibition and activation

Advances in the carbonic anhydrase (CA, EC 4.2.1.1) research over the last three decades are presented, with an emphasis on the deciphering of the activation mechanism, the development of isoform-selective inhibitors/ activators by the tail approach and their applications in the management of obesity, hypoxic tumors, neurological conditions, and as antiinfectives.