The development of a heme-responsive biosensor for dynamic pathway regulation in eukaryotes has never been reported, posing a challenge for achieving the efficient synthesis of multifunctional hemoproteins and maintaining intracellular heme homeostasis. Herein, a biosensor containing a newly identified heme-responsive promoter, CRISPR/dCas9, and a degradation tag N-degron was designed and optimized to fine-tune heme biosynthesis in the efficient heme-supplying Pichia pastoris P1H9 chassis. After identifying literature-reported promoters insensitive to heme, the endogenous heme-responsive promoters were mined by transcriptomics, and an optimal biosensor was screened from different combinations of regulatory elements. The dynamic regulation pattern of the biosensor was validated by the transcriptional fluctuations of the HEM2 gene involved in heme biosynthesis and the subsequent responsive changes in intracellular heme titers. We demonstrate the efficiency of this regulatory system by improving the production of high-active porcine myoglobin and soy hemoglobin, which can be used to develop artificial meat and artificial metalloenzymes. Moreover, these findings can offer valuable strategies for the synthesis of other hemoproteins.
Electrochemical nitrate reduction (NO3RR) provides a new option to abate nitrate contamination with a low carbon footprint. Restricted by competitive hydrogen evolution, achieving satisfied nitrate reduction performance in neutral media is still a challenge, especially for the regulation of this multielectron multiproton reaction. Herein, facile element doping is adopted to tune the catalytic behavior of IrNi alloy nanobranches with an unconventional hexagonal close-packed (hcp) phase toward NO3RR. In particular, the obtained hcp IrNiCu nanobranches favor the ammonia production and suppress byproduct formation in a neutral electrolyte indicated by in situ differential electrochemical mass spectrometry, with a high Faradaic efficiency (FE) of 85.6% and a large yield rate of 1253 µg cm-2 h-1 at -0.4 and -0.6 V (vs reversible hydrogen electrode (RHE)), respectively. In contrast, the resultant hcp IrNiCo nanobranches promote the formation of nitrite, with a peak FE of 33.1% at -0.1 V (vs RHE). Furthermore, a hybrid electrolysis cell consisting of NO3RR and formaldehyde oxidation is constructed, which are both catalyzed by hcp IrNiCu nanobranches. This electrolyzer exhibits lower overpotential and holds the potential to treat polluted air and wastewater simultaneously, shedding light on green chemical production based on contaminate degradation.
Transcription factors (TFs) are proteins essential for regulating genetic transcriptions by binding to transcription factor binding sites (TFBSs) in DNA sequences. Accurate predictions of TFBSs can contribute to the design and construction of metabolic regulatory systems based on TFs. Although various deep-learning algorithms have been developed for predicting TFBSs, the prediction performance needs to be improved. This paper proposes a bidirectional encoder representations from transformers (BERT)-based model, called BERT-TFBS, to predict TFBSs solely based on DNA sequences. The model consists of a pre-trained BERT module (DNABERT-2), a convolutional neural network (CNN) module, a convolutional block attention module (CBAM) and an output module. The BERT-TFBS model utilizes the pre-trained DNABERT-2 module to acquire the complex long-term dependencies in DNA sequences through a transfer learning approach, and applies the CNN module and the CBAM to extract high-order local features. The proposed model is trained and tested based on 165 ENCODE ChIP-seq datasets. We conducted experiments with model variants, cross-cell-line validations and comparisons with other models. The experimental results demonstrate the effectiveness and generalization capability of BERT-TFBS in predicting TFBSs, and they show that the proposed model outperforms other deep-learning models. The source code for BERT-TFBS is available at https://github.com/ZX1998-12/BERT-TFBS.
Neural Networks, Computer , Transcription Factors , Transcription Factors/metabolism , Transcription Factors/genetics , Binding Sites , Algorithms , Computational Biology/methods , Humans , Deep Learning , Protein Binding
To enhance the import of heme for the production of active hemoproteins in Escherichia coli C41 (DE3) lacking the special heme import system, heme receptor ChuA from E. coli Nissle 1917 was modified through molecular docking and the other components (ChuTUV) for heme import was overexpressed, while heme import was tested through growth assay and heme sensor HS1 detection. A ChuA mutant G360K was selected, which could import 3.91 nM heme, compared with 2.92 nM of the wild-type ChuA. In addition, it presented that the expression of heme transporters ChuTUV was not necessary for heme import. Based on the modification of ChuA (G360K), the titer of human hemoglobin and the peroxidase activity of leghemoglobin reached 1.19 µg g-1 DCW and 24.16 103 U g-1 DCW, compared with 1.09 µg g-1 DCW and 21.56 103 U g-1 DCW of the wild-type ChuA, respectively. Heme import can be improved through the modification of heme receptor and the engineered strain with improved heme import has a potential to efficiently produce high-active hemoproteins.
BACKGROUND: Exercise-induced physiological cardiac growth regulators may protect the heart from ischemia/reperfusion (I/R) injury. Homeobox-containing 1 (Hmbox1), a homeobox family member, has been identified as a putative transcriptional repressor and is downregulated in the exercised heart. However, its roles in exercise-induced physiological cardiac growth and its potential protective effects against cardiac I/R injury remain largely unexplored. METHODS: We studied the function of Hmbox1 in exercise-induced physiological cardiac growth in mice after 4 weeks of swimming exercise. Hmbox1 expression was then evaluated in human heart samples from deceased patients with myocardial infarction and in the animal cardiac I/R injury model. Its role in cardiac I/R injury was examined in mice with adeno-associated virus 9 (AAV9) vector-mediated Hmbox1 knockdown and in those with cardiac myocyte-specific Hmbox1 ablation. We performed RNA sequencing, promoter prediction, and binding assays and identified glucokinase (Gck) as a downstream effector of Hmbox1. The effects of Hmbox1 together with Gck were examined in cardiomyocytes to evaluate their cell size, proliferation, apoptosis, mitochondrial respiration, and glycolysis. The function of upstream regulator of Hmbox1, ETS1, was investigated through ETS1 overexpression in cardiac I/R mice in vivo. RESULTS: We demonstrated that Hmbox1 downregulation was required for exercise-induced physiological cardiac growth. Inhibition of Hmbox1 increased cardiomyocyte size in isolated neonatal rat cardiomyocytes and human embryonic stem cell-derived cardiomyocytes but did not affect cardiomyocyte proliferation. Under pathological conditions, Hmbox1 was upregulated in both human and animal postinfarct cardiac tissues. Furthermore, both cardiac myocyte-specific Hmbox1 knockout and AAV9-mediated Hmbox1 knockdown protected against cardiac I/R injury and heart failure. Therapeutic effects were observed when sh-Hmbox1 AAV9 was administered after I/R injury. Inhibition of Hmbox1 activated the Akt/mTOR/P70S6K pathway and transcriptionally upregulated Gck, leading to reduced apoptosis and improved mitochondrial respiration and glycolysis in cardiomyocytes. ETS1 functioned as an upstream negative regulator of Hmbox1 transcription, and its overexpression was protective against cardiac I/R injury. CONCLUSIONS: Our studies unravel a new role for the transcriptional repressor Hmbox1 in exercise-induced physiological cardiac growth. They also highlight the therapeutic potential of targeting Hmbox1 to improve myocardial survival and glucose metabolism after I/R injury.
BACKGROUND: Chronic myeloid leukemia (CML) is a common hematological malignancy, and tyrosine kinase inhibitors (TKIs) represent the primary therapeutic approach for CML. Activation of metabolism signaling pathway has been connected with BCR::ABL1-independent TKIs resistance in CML cells. However, the specific mechanism by which metabolism signaling mediates this drug resistance remains unclear. Here, we identified one relationship between glutamine synthetase (GS) and BCR::ABL1-independent Imatinib resistance in CML cells. METHODS: GS and PXN-AS1 in bone marrow samples of CML patients with Imatinib resistance (IR) were screened and detected by whole transcriptome sequencing. GS expression was upregulated using LVs and blocked using shRNAs respectively, then GS expression, Gln content, and cell cycle progression were respectively tested. The CML IR mice model were established by tail vein injection, prognosis of CML IR mice model were evaluated by Kaplan-Meier analysis, the ratio of spleen/body weight, HE staining, and IHC. PXN-AS1 level was blocked using shRNAs, and the effects of PXN-AS1 on CML IR cells in vitro and in vivo were tested the same as GS. Several RNA-RNA tools were used to predict the potential target microRNAs binding to both GS and PXN-AS1. RNA mimics and RNA inhibitors were used to explore the mechanism through which PXN-AS1 regulates miR-635 or miR-635 regulates GS. RESULTS: GS was highly expressed in the bone marrow samples of CML patients with Imatinib resistance. In addition, the lncRNA PXN-AS1 was found to mediate GS expression and disorder cell cycle in CML IR cells via mTOR signaling pathway. PXN-AS1 regulated GS expression by binding to miR-635. Additionally, knockdown of PXN-AS1 attenuated BCR::ABL1-independent Imatinib resistance in CML cells via PXN-AS1/miR-635/GS/Gln/mTOR signaling pathway. CONCLUSIONS: Thus, PXN-AS1 promotes GS-mediated BCR::ABL1-independent Imatinib resistance in CML cells via cell cycle signaling pathway.
Electrocatalytic carbon dioxide reduction reaction (CO2RR) has emerged as a promising and sustainable approach to cut carbon emissions by converting greenhouse gas CO2 to value-added chemicals and fuels. Metal-organic coordination compounds, especially the copper (Cu)-based coordination compounds, which feature well-defined crystalline structures and designable metal active sites, have attracted much research attention in electrocatalytic CO2RR. Herein, the recent advances of electrochemical CO2RR on pristine Cu-based coordination compounds with different types of Cu active sites are reviewed. First, the general reaction pathways of electrocatalytic CO2RR on Cu-based coordination compounds are briefly introduced. Then the highly efficient conversion of CO2 on various kinds of Cu active sites (e.g., single-Cu site, dimeric-Cu site, multi-Cu site, and heterometallic site) is systematically discussed, along with the corresponding catalytic reaction mechanisms. Finally, some existing challenges and potential opportunities for this research direction are provided to guide the rational design of metal-organic coordination compounds for their practical application in electrochemical CO2RR.
The highly reversible plating/stripping of Zn is plagued by dendrite growth and side reactions on metallic Zn anodes, retarding the commercial application of aqueous Zn-ion batteries. Herein, a distinctive nano dual-phase diamond (NDPD) comprised of an amorphous-crystalline heterostructure is developed to regulate Zn deposition and mechanically block dendrite growth. The rich amorphous-crystalline heterointerfaces in the NDPD endow modified Zn anodes with enhanced Zn affinity and result in homogeneous nucleation. In addition, the unparalleled hardness of the NDPD effectively overcomes the high growth stress of dendrites and mechanically impedes their proliferation. Moreover, the hydrophobic surfaces of the NDPD facilitate the desolvation of hydrate Zn2+ and prevent water-mediated side reactions. Consequently, the Zn@NDPD presents an ultrastable lifespan exceeding 3200 h at 5 mA cm-2 and 1 mAh cm-2. The practical application potential of Zn@NDPD is further demonstrated in full cells. This work exhibits the great significance of a chemical-mechanical synergistic anode modification strategy in constructing high-performance aqueous Zn-ion batteries.
The titer of the microbial fermentation products can be increased by enzyme engineering. l-Sorbosone dehydrogenase (SNDH) is a key enzyme in the production of 2-keto-l-gulonic acid (2-KLG), which is the precursor of vitamin C. Enhancing the activity of SNDH may have a positive impact on 2-KLG production. In this study, a computer-aided semirational design of SNDH was conducted. Based on the analysis of SNDH's substrate pocket and multiple sequence alignment, three modification strategies were established: (1) expanding the entrance of SNDH's substrate pocket, (2) engineering the residues within the substrate pocket, and (3) enhancing the electron transfer of SNDH. Finally, mutants S453A, L460V, and E471D were obtained, whose specific activity was increased by 20, 100, and 10%, respectively. In addition, the ability of Gluconobacter oxidans WSH-004 to synthesize 2-KLG was improved by eliminating H2O2. This study provides mutant enzymes and metabolic engineering strategies for the microbial-fermentation-based production of 2-KLG.
Bacterial Proteins , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Gluconobacter/enzymology , Gluconobacter/genetics , Gluconobacter/metabolism , Sugar Acids/metabolism , Sugar Acids/chemistry , Fermentation , Protein Engineering , Metabolic Engineering , Carbohydrate Dehydrogenases/metabolism , Carbohydrate Dehydrogenases/genetics , Carbohydrate Dehydrogenases/chemistry , Kinetics
Pectin lyases (PNLs) can enhance juice clarity and flavor by degrading pectin in highly esterified fruits, but their inadequate acid resistance leads to rapid activity loss in juice. This study aimed to improve the acid resistance of Aspergillus niger PNL pelA through surface charge design. A modification platform was established by fusing pelA with a protein tag and expressing the fusion enzyme in Escherichia coli. Four single-point mutants were identified to increase the surface charge using computational tools. Moreover, the combined mutant M6 (S514D/S538E) exhibited 99.8% residual activity at pH 3.0. The M6 gene was then integrated into the A. niger genome using a multigene integration system to obtain the recombinant PNL AM6. Notably, AM6 improved the light transmittance of orange juice to 45.3%, which was 8.39 times higher than that of pelA. In conclusion, AM6 demonstrated the best-reported acid resistance, making it a promising candidate for industrial juice clarification.
Aspergillus niger , Fruit and Vegetable Juices , Fungal Proteins , Polysaccharide-Lyases , Aspergillus niger/enzymology , Aspergillus niger/genetics , Fruit and Vegetable Juices/analysis , Polysaccharide-Lyases/genetics , Polysaccharide-Lyases/metabolism , Polysaccharide-Lyases/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Hydrogen-Ion Concentration , Food Handling , Acids/chemistry , Acids/metabolism , Acids/pharmacology , Citrus sinensis/chemistry , Pectins/chemistry , Pectins/metabolism , Enzyme Stability
Copper (Cu) nanomaterials are a unique kind of electrocatalysts for high-value multi-carbon production in carbon dioxide reduction reaction (CO2RR), which holds enormous potential in attaining carbon neutrality. However, phase engineering of Cu nanomaterials remains challenging, especially for the construction of unconventional phase Cu-based asymmetric heteronanostructures. Here the site-selective growth of Cu on unusual phase gold (Au) nanorods, obtaining three kinds of heterophase fcc-2H-fcc Au-Cu heteronanostructures is reported. Significantly, the resultant fcc-2H-fcc Au-Cu Janus nanostructures (JNSs) break the symmetric growth mode of Cu on Au. In electrocatalytic CO2RR, the fcc-2H-fcc Au-Cu JNSs exhibit excellent performance in both H-type and flow cells, with Faradaic efficiencies of 55.5% and 84.3% for ethylene and multi-carbon products, respectively. In situ characterizations and theoretical calculations reveal the co-exposure of 2H-Au and 2H-Cu domains in Au-Cu JNSs diversifies the CO* adsorption configurations and promotes the CO* spillover and subsequent C-C coupling toward ethylene generation with reduced energy barriers.
Gluconobacter oxydans is an important Gram-negative industrial microorganism that produces vitamin C and other products due to its efficient membrane-bound dehydrogenase system. Its incomplete oxidation system has many crucial industrial applications. However, it also leads to slow growth and low biomass, requiring further metabolic modification for balancing the cell growth and incomplete oxidation process. As a non-model strain, G. oxydans lacks efficient genome editing tools and cannot perform rapid multi-gene editing and complex metabolic network regulation. In the last 15 years, our laboratory attempted to deploy multiple CRISPR/Cas systems in different G. oxydans strains and found none of them as functional. In this study, Cpf1-based or dCpf1-based CRISPRi was constructed to explore the targeted binding ability of Cpf1, while Cpf1-FokI was deployed to study its nuclease activity. A study on Cpf1 found that the CRISPR/Cpf1 system could locate the target genes in G. oxydans but lacked the nuclease cleavage activity. Therefore, the CRISPR/Cpf1-FokI system based on FokI nuclease was constructed. Single-gene knockout with efficiency up to 100% and double-gene iterative editing were achieved in G. oxydans. Using this system, AcrVA6, the anti-CRISPR protein of G. oxydans was discovered for the first time, and efficient genome editing was realized.
Difucosyllactose (DFL) is a significant and plentiful oligosaccharide found in human breast milk. In this study, an artificial metabolic pathway of DFL was designed, focusing on the de novo biosynthesis of GDP-fucose from only glycerol. This was achieved by engineering Escherichia coli to endogenously overexpress genes manB, manC, gmd, and wcaG and heterologously overexpress a pair of fucosyltransferases to produce DFL from lactose. The introduction of α-1,2-fucosyltransferase from Helicobacter pylori (FucT2) along with α-1,3/4-fucosyltransferase (HP3/4FT) addressed rate-limiting challenges in enzymatic catalysis and allowed for highly efficient conversion of lactose into DFL. Based on these results, molecular modification of HP3/4FT was performed based on computer-assisted screening and structure-based rational design. The best-performing mutant, MH5, containing a combination of five mutated sites (F49K/Y131D/Y197N/E338D/R369A) of HP3/4FT was obtained. The best strain BLC09-58 harboring MH5 yielded 45.81 g/L of extracellular DFL in 5-L fed-batch cultures, which was the highest titer reported to date.
Rebaudioside (Reb) M is an important sweetener with high sweetness, but its low content in Stevia rebaudiana and low catalytic capacity of the glycosyltransferases in heterologous microorganisms limit its production. In order to improve the catalytic efficiency of the conversion of stevioside to Reb M by Saccharomyces cerevisiae, several key issues must be resolved including knocking out endogenous hydrolases, enhancing glycosylation, and extending the enzyme catalytic process. Herein, endogenous glycosyl hydrolase SCW2 was knocked out in S. cerevisiae. The glycosylation process was enhanced by screening glycosyltransferases, and UGT91D2 from S. rebaudiana was identified as the optimum glycosyltransferase. The UDP-glucose supply was enhanced by overexpressing UGP1, and co-expressing UGT91D2 and UGT76G1 achieved efficient conversion of stevioside to Reb M. In order to extend the catalytic process, the silencing information regulator 2 (SIR2) which can prolong the growth cycle of S. cerevisiae was introduced. Finally, combining these modifications produced 12.5 g/L Reb M and the yield reached 77.9% in a 5 L bioreactor with 10.0 g/L stevioside, the highest titer from steviol glycosides to Reb M reported to date. The engineered strain could facilitate the industrial production of Reb M, and the strategies provide references for the production of steviol glycosides.
Diterpenes, Kaurane , Stevia , Trisaccharides , Saccharomyces cerevisiae/genetics , Uridine Diphosphate , Hydrolases , Glucosides , Glycosyltransferases/genetics , Glycosides , Plant Leaves
Quinoa sprouts are a green vegetable rich in bioactive chemicals, which have multiple health benefits. However, there is limited information on the overall metabolic profiles of quinoa sprouts and the metabolite changes caused by saline-alkali stress. Here, a UHPLC-MS/MS-based widely targeted metabolomics technique was performed to comprehensively evaluate the metabolic profiles of quinoa sprouts and characterize its metabolic response to saline-alkali stress. A total of 930 metabolites were identified of which 232 showed significant response to saline-alkali stress. The contents of lipids and amino acids were significantly increased, while the contents of flavonoids and phenolic acids were significantly reduced under saline-alkali stress. Moreover, the antioxidant activities of quinoa sprouts were significantly affected by saline-alkali stress. The enrichment analysis of the differentially accumulated metabolites revealed that flavonoid, amino acid and carbohydrate biosynthesis/metabolism pathways responded to saline-alkali stress. This study provided an important theoretical basis for evaluating the nutritional value of quinoa sprouts and the changes in metabolites in response to saline-alkali stress.
Alkalies , Chenopodium quinoa , Flavonoids , Nutritive Value , Chenopodium quinoa/chemistry , Chenopodium quinoa/metabolism , Chenopodium quinoa/growth & development , Alkalies/chemistry , Alkalies/metabolism , Flavonoids/metabolism , Flavonoids/analysis , Flavonoids/chemistry , Chromatography, High Pressure Liquid , Antioxidants/metabolism , Antioxidants/chemistry , Metabolomics , Tandem Mass Spectrometry , Amino Acids/metabolism , Amino Acids/analysis , Stress, Physiological
Gamma-aminobutyric acid (GABA) is a non-protein amino acid which is widely applied in agriculture and pharmaceutical additive industries. GABA is synthesized from glutamate through irreversible α-decarboxylation by glutamate decarboxylase. Recently, microbial synthesis has become an inevitable trend to produce GABA due to its sustainable characteristics. Therefore, reasonable microbial platform design and metabolic engineering strategies for improving production of GABA are arousing a considerable attraction. The strategies concentrate on microbial platform optimization, fermentation process optimization, rational metabolic engineering as key metabolic pathway modification, promoter optimization, site-directed mutagenesis, modular transporter engineering, and dynamic switch systems application. In this review, the microbial producers for GABA were summarized, including lactic acid bacteria, Corynebacterium glutamicum, and Escherichia coli, as well as the efficient strategies for optimizing them to improve the production of GABA.
Corynebacterium glutamicum , gamma-Aminobutyric Acid , Agriculture , Corynebacterium glutamicum/genetics , Drug Industry , Engineering , Escherichia coli/genetics
Multiplexing orbital angular momentum (OAM) modes enable high-capacity optical communication. However, the highly similar speckle patterns of adjacent OAM modes produced by strong mode coupling in common fibers prevent the utility of OAM channel demultiplexing. In this paper, we propose a machine learning-supported fractional OAM-multiplexed data transmission system to sort highly scattered data from up to 32 multiplexed OAM channels propagating through a commercial multi-mode fiber parallelly with an accuracy of >99.92%, which is the largest bit number of OAM superstates reported to date (to the best of our knowledge). Here, by learning limited samples, unseen OAM superstates during the training process can be predicted precisely, which reduces the explosive quantity of the dataset. To verify its application, both gray and colored images, encoded by the given system, have been successfully transmitted with error rates of <0.26%. Our work might provide a promising avenue for high-capacity OAM optical communication in scattering environments.
Retinol is a lipid-soluble form of vitamin A that is crucial for human visual and immune functions. The production of retinol through microbial fermentation has been the focus of recent exploration. However, the obtained titer remains limited and the product is often a mixture of retinal, retinol, and retinoic acid, necessitating purification. To achieve efficient biosynthesis of retinol in Yarrowia lipolytica, we improved the metabolic flux of ß-carotene to provide sufficient precursors for retinol in this study. Coupled with the optimization of the expression level of ß-carotene 15,15'-dioxygenase, de novo production of retinol was achieved. Furthermore, Tween 80 was used as an extractant and butylated hydroxytoluene as an antioxidant to extract intracellular retinol and prevent retinol oxidation, respectively. This strategy significantly increased the level of retinol production. By optimizing the enzymes converting retinal to retinol, the proportion of extracellular retinol in the produced retinoids reached 100%, totaling 1042.3 mg/L. Finally, total retinol production reached 5.4 g/L through fed-batch fermentation in a 5 L bioreactor, comprising 4.2 g/L extracellular retinol and 1.2 g/L intracellular retinol. This achievement represents the highest reported titer so far and advances the industrial production of retinol.
Vitamin A , Yarrowia , Humans , Vitamin A/metabolism , Fermentation , Yarrowia/genetics , Yarrowia/metabolism , Bioreactors , beta Carotene/metabolism , Metabolic Networks and Pathways , Metabolic Engineering
Chalcone synthase (CHS) catalyzes the rate-limiting step of (2S)-naringenin (the essential flavonoid skeleton) biosynthesis. Improving the activity of the CHS by protein engineering enhances (2S)-naringenin production by microbial fermentation and can facilitate the production of valuable flavonoids. A (2S)-naringenin biosensor based on the TtgR operon was constructed in Escherichia coli and its detection range was expanded by promoter optimization to 0-300 mg/L, the widest range for (2S)-naringenin reported. The high-throughput screening scheme for CHS was established based on this biosensor. A mutant, SjCHS1S208N with a 2.34-fold increase in catalytic activity, was discovered by directed evolution and saturation mutagenesis. A pathway for de novo biosynthesis of (2S)-naringenin by SjCHS1S208N was constructed in Saccharomyces cerevisiae, combined with CHS precursor pathway optimization, increasing the (2S)-naringenin titer by 65.34% compared with the original strain. Fed-batch fermentation increased the titer of (2S)-naringenin to 2513 ± 105 mg/L, the highest reported so far. These findings will facilitate efficient flavonoid biosynthesis and further modification of the CHS in the future.
Acyltransferases , Biosensing Techniques , Directed Molecular Evolution , Escherichia coli , Fermentation , Flavanones , Saccharomyces cerevisiae , Flavanones/biosynthesis , Flavanones/metabolism , Acyltransferases/genetics , Acyltransferases/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Directed Molecular Evolution/methods , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Biosensing Techniques/methods , Protein Engineering/methods , Promoter Regions, Genetic , Operon/genetics , Metabolic Engineering/methods
Synthesis of ammonia by electrochemical nitrogen reduction reaction (NRR) is a promising alternative to the Haber-Bosch process. However, it is commonly obstructed by the high activation energy. Here, we report the design and synthesis of an Al-Al bonded dual atomic catalyst stabilized within an amorphous nitrogen-doped porous carbon matrix (Al2NC) with high NRR performance. The dual atomic Al2-sites act synergistically to catalyze the complex multiple steps of NRR through adsorption and activation, enhancing the proton-coupled electron transfer. This Al2NC catalyst exhibits a high Faradaic efficiency of 16.56±0.3 % with a yield rate of 29.22±1.2â µg h-1 mgcat -1. The dual atomic Al2NC catalyst shows long-term repeatable, and stable NRR performance. This work presents an insight into the identification of synergistic dual atomic catalytic site and mechanistic pathway for the electrochemical conversion of N2 to NH3.
