Efficient CO2-Reducing Activity of NAD-Dependent Formate Dehydrogenase from Thiobacillus sp KNK65MA for Formate Production from CO2 Gas

NAD-dependent formate dehydrogenase (FDH) from Candida boidinii (CbFDH) has been widely used in various CO2 reduction systems but its practical applications are often impeded due to low CO2-reducing activity. In this study, we demonstrated superior CO2-reducing properties of FDH from Thiobacillus sp. KNK65MA (TsFDH) for production of formate from CO2 gas. To discover more efficient CO2-reducing FDHs than a reference enzyme e. CbFDH, five FDHs were selected with biochemical properties and then, their CO2-reducing activities were evaluated. All FDHs including CbFDH showed better CO2-reducing activities at acidic pHs than at neutral pHs and four FDHs were more active than CbFDH in the CO2 reduction reaction. In particular, the FDH from Thiobacillus sp. KNK65IVIA (TsFDH) exhibited the highest CO2-reducing activity and had a dramatic preference for the reduction reaction, i.e., a 84.2-fold higher ratio of CO2 reduction to formate oxidation in catalytic efficiency (k(cat)/K-B) compared to CbFDH. Formate was produced from CO2 gas using TsFDH and CbFDH, and TsFDH showed a 5.8-fold higher formate production rate than CbFDH. A sequence and structural comparison showed that FDHs with relatively high CO2-reducing activities had elongated N- and C-terminal loops. The experimental results demonstrate that TsFDH can be an alternative to CbFDH as a biocatalyst in CO2 reduction systemsope

Is diet partly responsible for differences in COVID-19 death rates between and within countries?

Correction: Volume: 10 Issue: 1 Article Number: 44 DOI: 10.1186/s13601-020-00351-w Published: OCT 26 2020Reported COVID-19 deaths in Germany are relatively low as compared to many European countries. Among the several explanations proposed, an early and large testing of the population was put forward. Most current debates on COVID-19 focus on the differences among countries, but little attention has been given to regional differences and diet. The low-death rate European countries (e.g. Austria, Baltic States, Czech Republic, Finland, Norway, Poland, Slovakia) have used different quarantine and/or confinement times and methods and none have performed as many early tests as Germany. Among other factors that may be significant are the dietary habits. It seems that some foods largely used in these countries may reduce angiotensin-converting enzyme activity or are anti-oxidants. Among the many possible areas of research, it might be important to understand diet and angiotensin-converting enzyme-2 (ACE2) levels in populations with different COVID-19 death rates since dietary interventions may be of great benefit.Peer reviewe

Carbon Dioxide Utilisation -The Formate Route

UIDB/50006/2020 CEEC-Individual 2017 Program Contract.The relentless rise of atmospheric CO2 is causing large and unpredictable impacts on the Earth climate, due to the CO2 significant greenhouse effect, besides being responsible for the ocean acidification, with consequent huge impacts in our daily lives and in all forms of life. To stop spiral of destruction, we must actively reduce the CO2 emissions and develop new and more efficient “CO2 sinks”. We should be focused on the opportunities provided by exploiting this novel and huge carbon feedstock to produce de novo fuels and added-value compounds. The conversion of CO2 into formate offers key advantages for carbon recycling, and formate dehydrogenase (FDH) enzymes are at the centre of intense research, due to the “green” advantages the bioconversion can offer, namely substrate and product selectivity and specificity, in reactions run at ambient temperature and pressure and neutral pH. In this chapter, we describe the remarkable recent progress towards efficient and selective FDH-catalysed CO2 reduction to formate. We focus on the enzymes, discussing their structure and mechanism of action. Selected promising studies and successful proof of concepts of FDH-dependent CO2 reduction to formate and beyond are discussed, to highlight the power of FDHs and the challenges this CO2 bioconversion still faces.publishersversionpublishe

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Soft- and hard-templated organic salt nanoparticles with the Midas touch: Gold-shelled nanoGUMBOS

© the Partner Organisations 2014. An emerging thrust in the design of advanced materials is nanoscale functional materials possessing multiple capabilities, such as those possessing a core-shell architecture. Nanoparticles comprising a dielectric core (e.g., silica, polystyrene) and a gold shell are particularly attractive due to the desirable optical (plasmonic) and biocompatibility characteristics of gold. While these materials are bio-inert, they generally present limited tunability. In this regard, a core composed of a solid-state ionic liquid represents an interesting and unexplored alternative for generating unique core-shell architectures. In recent years, we have developed an emergent class of morphology-controlled tailored organic salt particles, so-called GUMBOS (group of materials based on organic salts). GUMBOS are reminiscent of traditional ionic liquids with the important distinction that they possess elevated melting points (generally, from 100 to 250 °C), making possible the fabrication of ambient-stable nanoscale salts of various sizes, compositions, and morphologies by means of a variety of thermal, sonochemical, colloidal, or hard-template synthetic routes. In this work, we advance our recent examination of GUMBOS to demonstrate proof of concept for their use in elaborating novel plasmonic nanostructures by using a seed-mediated growth to generate gold shells atop nanoscale quasi-spherical GUMBOS as well as uni-dimensional GUMBOS nanorods. We present here our general strategy for preparing gold-shelled nanoGUMBOS, alongside systematic monitoring of the evolution of the gold-coating process. We also report on a preliminary investigation of the catalytic properties of the near-infrared absorbing gold-shelled nanorod GUMBOS in the reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride. This journal i

Electro-optical characterization of nanoGUMBOS

Molecular electronics, where nanoscale organic species are utilized as active electronic components, offers a promising approach towards ultimate miniaturization and integration of hybrid electronic materials (HEMs) with traditional silicon based complementary metal oxide semiconductors (CMOS) technology. Toward this end, fundamental research studies to understand the electronic and optical properties of these molecules are of paramount importance. In this work, conductive probe atomic force microscopy (CP-AFM) and Raman spectroscopy have been performed on ionic liquid based unique organic nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (GUMBOS). Aptly named as nanoGUMBOS, the material investigated in this report is Rhodamine6G tetraphenylborate ([R6G][TPB]) as has been synthesized by a room temperature facile metathesis reaction between Rhodamine 6G chloride (R6GCl) and sodium tetraphenylborate (NaTPB) followed by an ultrasonication-assisted, additive-free, re-precipitation reaction. To the best of our knowledge, the results reported herein are first-time evidence of electrical performance exhibited by [R6G][TPB] nanoGUMBOS. In conjunction with the supportive results of Raman spectra, the current-voltage (I-V) characteristics obtained are indicative of the potential incorporation of this unique compound in hybrid electronics with respect to potential applications in optoelectronics and chemical sensing. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht