英国剑桥大学Sutherland, John D.团队报道了二氧化碳和亚硫酸盐的光氧化还原合成益生元。相关研究成果发表在2021年10月11日出版的《自然—化学》。

二氧化碳（CO₂）是许多行星大气的主要含碳成分，包括地球的整个历史。碳固定化学利用氢作为化学计量还原剂将二氧化碳还原为有机物，通常需要高压和高温，并且潜在用于新生生物的产品产量较低。

该文中，研究人员展示了二氧化碳和亚硫酸盐之间高效的紫外光解化学，产生有机物和硫酸盐。该化学反应是由亚硫酸盐的电子光剥离引发的，产生亚硫酸盐自由基和水合电子，从而将二氧化碳还原为自由基阴离子。还揭示了在亚硫酸盐存在下通过乙醇酸盐的辐照生成柠檬酸盐、苹果酸盐、琥珀酸盐和酒石酸盐的反应过程。该羧基亚硫酸盐化学的简单性及其原料的广泛存在和丰富性表明，其可能很容易发生在岩石行星的表面。在生物固碳技术出现之前，早期地球上羧酸盐产品的可用性可能已经推动了中心碳代谢的发展。

附：英文原文

Title: Prebiotic photoredox synthesis from carbon dioxide and sulfite

Author: Liu, Ziwei, Wu, Long-Fei, Kufner, Corinna L., Sasselov, Dimitar D., Fischer, Woodward W., Sutherland, John D.

Issue&Volume: 2021-10-11

Abstract: Carbon dioxide (CO2) is the major carbonaceous component of many planetary atmospheres, which includes the Earth throughout its history. Carbon fixation chemistry—which reduces CO2 to organics, utilizing hydrogen as the stoichiometric reductant—usually requires high pressures and temperatures, and the yields of products of potential use to nascent biology are low. Here we demonstrate an efficient ultraviolet photoredox chemistry between CO2 and sulfite that generates organics and sulfate. The chemistry is initiated by electron photodetachment from sulfite to give sulfite radicals and hydrated electrons, which reduce CO2 to its radical anion. A network of reactions that generates citrate, malate, succinate and tartrate by irradiation of glycolate in the presence of sulfite was also revealed. The simplicity of this carboxysulfitic chemistry and the widespread occurrence and abundance of its feedstocks suggest that it could have readily taken place on the surfaces of rocky planets. The availability of the carboxylate products on early Earth could have driven the development of central carbon metabolism before the advent of biological CO2 fixation.

DOI: 10.1038/s41557-021-00789-w

Source: https://www.nature.com/articles/s41557-021-00789-w