Photosynthesis of Acetate by Sporomusa ovata–CdS Biohybrid System

Abstract

Sporomusa ovata, a typical electroautotrophic microorganism, has been utilized in bioelectrosynthesis for carbon dioxide fixation to multicarbon organic chemicals. However, additional photovoltaic devices are normally needed to convert photo energy to electric energy to power the carbon dioxide fixation, which restricts the overall energy conversion efficiency. Herein, we report Sporomusa ovata−CdS biohybrids for artificial photosynthesis driven by light without any other power source. The quantum yield can reach 16.8 ± 9%, and the active duration time of the system can last for 5 days. During the artificial photosynthesis, carbon dioxide is first reduced to formate and finally converted to acetate via the Wood−Ljungdahl pathway. The carbon dioxide fixation, electron transfer, energy metabolism, and reactive oxygen species damage repair processes in the biohybrid system were characterized by proteomic analysis. Key enzymes, e.g., flavoprotein, ferredoxin, formate-tetrahydrofolate ligase, 5-methyltetrahydrofolate:corrinoid iron−sulfur protein methyltransferase, thioredoxin, and rubrerythrin, were found up-regulated in the biohybrid system. The findings are helpful in understanding the mechanism of the artificial photosynthesis and useful for the development of new biohybrid systems using genetically engineered microbes in the future. The study is expected to boost the development of bioabiotic hybrid system in solar energy harvest.

Photodriven Chemical Synthesis by Whole-Cell-Based Biohybrid Systems: From System Construction to Mechanism Study

“…Besides M. thermoacetica , other acetogens have also been utilized to construct PBSs. Sporomusa ovata ( S. ovata ) is one of the acetogens as well as electro-active bacteria (EAB) and has been utilized in microbial electrosynthesis systems for CO 2 fixation, driven by electricity directly , or electricity converted from solar energy by photovoltaic devices. , He et al proposed a PBS based on S. ovata by bioprecipitating CdS-NPs onto its surface through an analogical process of M. thermoacetica -CdS construction. The S. ovata -CdS biohybrid reaches a high QY of 16.8 ± 9% and an active duration time of 5 days.…”

“…Both of the two metabolic pathways were involved in providing large amounts of reducing equivalents (NADH) and ATP for the WLP. Inspired by the work of M. thermoacetica -CdS biohybrid system, He et al proposed the S.ovata -CdS biohybrid for CO 2 reduction. Proteomic and metabolomic methodologies, were also utilized in the mechanism study of the PBS, which revealed that some key proteins, e.g., Fd, Fp, formate-tetrahydrofolate ligase (Fhs), 5-methyltetrahydrofolate/corrinoid iron–sulfur protein methyltransferase (MeTr), thioredoxin, and rubrerythrin, were expressed at high levels in the presence of CdS and under light irradiation.…”

Photosynthetic Polymer Dots–Bacteria Biohybrid System Based on Transmembrane Electron Transport for Fixing CO2 into Poly-3-hydroxybutyrate

“…Microbial synthesis is the use of organic matter and carbon dioxide (CO 2 ) through a wide range of microbial metabolic pathways and a variety of synthase production to produce high-value-added chemicals, such as biofuels, drug precursors, and biological materials. − Compared with chemical synthesis, microbial synthesis is a more effective and environmentally friendly method . Based on the biohybrid semiconductor–microbial photosynthetic system, − one can convert and store solar energy into chemical energy, such as hydrogen production, , CO 2 reduction, ,− and N 2 fixation. − In the photosynthetic biohybrid system, artificial photosensitizers, i.e., semiconductors are used to harvest light and generate electrons, which can be further transported by electron transport protein to reach the rich metabolic pathways in the bacteria for biosynthesis. Generally, inorganic photosynthetic systems suffer from poor specificity, generating only simple C1 products (CO, methanol, methane, or formic acid).…”

Self-Assembled Nanoscale Manganese Oxides Enhance Carbon Capture by Diatoms

“…The natural photosynthesis process is the best strategy for harnessing CO 2 from the air. , As one of the most abundant marine microorganisms, diatoms are responsible for more than 50% of global CO 2 fixation and account for approximately 40% of marine primary productivity . Combining phytoplankton with nanomaterials into biohybrid systems provides the potential to decrease atmospheric CO 2 levels. , However, the cytotoxicity and high cost of engineered nanomaterials limit the development of sustainable photosynthetic biohybrid systems. For example, most biocompatible materials (e.g., carbon or graphite) exert cyto- and genotoxic effects on stem cells, microorganisms, and even animals. , Engineered manganese-based nanomaterials have also been reported to be genotoxic in bivalve mollusks and plants. − In addition, nanomaterials derived from chemical synthesis often require highly pure reagents, high temperatures, or complex microfabrication techniques. , The development of novel methods to solve these key issues is urgently needed.…”

“…6 Combining phytoplankton with nanomaterials into biohybrid systems provides the potential to decrease atmospheric CO 2 levels. 7,8 However, the cytotoxicity and high cost of engineered nanomaterials limit the development of sustainable photosynthetic biohybrid systems. For example, most biocompatible materials (e.g., carbon or graphite) exert cyto-and genotoxic effects on stem cells, 9 microorganisms, 10 and even animals.…”