Optoelectronic Properties of MAPbBr3 Perovskite Light-Emitting Diodes Using Anti-Solvent and PEDOT:PSS/PVK Double-Layer Hole Transport Layers.

Perovskite light-emitting diodes (PeLEDs) have attracted extensive attention due to their advantages such as low-temperature solution processing, high photoluminescence quantum efficiency, high color purity, tunable wavelength, and excellent carrier mobility. The hole transport layer plays an important role in the device's performance. In this paper, the effect of anti-solvent (ethyl acetate) on the performance of PeLEDs was studied in order to determine the optimal anti-solvent condition. The effect of PEDOT:PSS/PVK double-layer hole transport layers on the optoelectronic properties of MAPbBr3 PeLEDs was investigated. The device with 8 mg/mL PVK produced the best results, with a maximum luminance of 5139 cd/m2 and a maximum current efficiency of 2.77 cd/A. Compared with the control device with PEDOT:PSS HTL, the maximum luminance of the device with 8 mg/mL PVK is increased by 2.02 times, and the maximum current efficiency is increased by 188%. The experimental results show that the addition of PVK helps to reduce the size of perovskite particles, contributing to the spatial confinement of excitons, and suppress the quenching of luminescence occurring at the interface between PEDOT:PSS and MAPbBr3, thereby enhancing the optoelectronic performance of PeLEDs. The results of this paper can provide a basis for the improvement and industrialization of PeLEDs.

Enhanced Performance of Perovskite Light-Emitting Diodes via Phenylmethylamine Passivation.

Organic-inorganic perovskite materials are widely used in the preparation of light-emitting diodes due to their low raw material cost, solution preparation, high color purity, high fluorescence quantum yield, continuously tunable spectrum, and excellent charge transport properties. It has become a research hotspot in the field of optoelectronics today. At present, the nonradiative recombination and fluorescence quenching occurring at the interface between the device transport layer and the light-emitting layer are still important factors limiting the performance of perovskite light-emitting diodes (PeLEDs). In this work, based on CH3NH3PbBr3 perovskite, the effects of parameters such as precursor solution, anti-solvent chlorobenzene (CB), and small amine molecule phenylmethylamine (PMA) on the performance of perovskite films and devices were investigated. The research results show that adding an appropriate amount of PMA can reduce the grain size of perovskite, improve the coverage of the film, enhance the crystallinity of the film, and increase the fluorescence intensity of the perovskite film. When the PMA content is 0.050 vol.%, the maximum luminance of PeLEDs is 2098 cd/m2 and the maximum current efficiency is 1.592 cd/A, which is greatly improved by 30% and 64.8% compared with the reference device without PMA doping. These results suggest that an appropriate amount of PMA can effectively passivate the defects in perovskite films, and inhibit the non-radiative recombination caused by the traps, thereby improving the optoelectronic performance of the device.

Progress of metal nanoclusters in nucleic acid detection.

The development and application of metal nanoclusters (MNCs) in nucleic acid testing in the past 10 years have been summarized. Fluorescence enhancement and red shift can occur when the G-rich sequence gets close to Ag NCs or the complementary DNA strand hybridizes with Ag NCs tail strand, which can be used to identify the nucleic acid. Ag NCs with the abasic site in DNA duplex can distinguish mutant genes such as cancer suppression gene p53. Ag NCs with auxiliary DNA can be used to detect miR-21, miR-16-5p, miR-19b-3p, and miR-141. Cu NCs/Cu NPs can recognize miRNA-155, miR-21, and miR-let-7d without auxiliary DNA. Au NCs can identify H1N1 gene fragments by fluorescence quenching caused by proximity to the G-rich sequence. Besides, Au NCs can recognize miRNA-21 and let-7a. SsDNA MNCs adsorbed on the surface of GO and CNPs oxide can be used to identify HBV and HIV gene fragments. The addition of enzymes or auxiliary amplification technologies is a popular way to improve probe sensitivity. Ag NCs combined with TAIEA has the best performance and can obtain LOD as low as aM for miRNA.

Enhanced performance of In2O3 nanowire field effect transistors with controllable surface functionalization of Ag nanoparticles.

Indium oxide (In2O3) nanowire field effect transistors (FETs) have great potential in electronic and sensor applications owing to their suitable band width and high electron mobility. However, the In2O3 nanowire FETs reported previously were operated in a depletion-mode, not suitable to the integrated circuits result of the high-power consumption. Therefore, tuning the electrical properties of In2O3 nanowire FETs into enhancement-mode is critical for the successful application in the fields of high-performance electronics, optoelectronics and detectors. In the work, a simple but effective strategy was carried out by preparing Ag nanoparticle functionalized In2O3 NWs to regulate the threshold voltage (Vth) of In2O3 NW FETs, successfully achieving enhanced-mode devices. The threshold voltage can be regulated from -6.9 V to +7 V by controlling Ag density via deposition time. In addition, the devices exhibited high performance: huge Ion/Ioff ratio > 108, large maximum saturation current ≈ 800 mA and excellent carrier mobility ≈ 129 cm2 Vcs-1. The enhanced performance is attributed to the surface passivation by Ag nanoparticles to reduce the density of traps and the charge transfer between traps and the nanowires to regulate the Vth. The result indicates the application of metal nanoparticles significantly improve oxide NW for low-power FETs.

Fabrication of rGO and g-C3N4 co-modified TiO2 nanotube arrays photoelectrodes with enhanced photocatalytic performance.

To enhance the photocatalytic performance of titanium dioxide (TiO2) and reduce the photocorrosion of graphitic carbon nitride (g-C3N4), two-dimensional (2D) reduced graphene oxide (rGO) and g-C3N4 co-modified three-dimensional (3D) TiO2 nanotube arrays (rGO@g-C3N4/TNAs) photoelectrodes were fabricated by the combination of impregnation, annealing and electrochemical cathode deposition. The micromorphology and microstructure were observed by SEM and TEM. The crystalline structure and element composition were characterized by XRD, XPS and Raman spectra. The optical and photo-electrochemical properties were analyzed by UV-vis DRS, open circuit potential and photocurrent density. Results indicated that g-C3N4 and rGO were successfully loaded on the surface of the TNAs photoelectrodes and formed rGO@g-C3N4/TNAs heterostructure. The photocatalytic activity of the photoelectrodes was evaluated by the degradation rate of tetracycline hydrochloride (TC) under xenon lamp irradiation. The introduction of g-C3N4 and rGO reduced the band gap of TNAs photoelectrodes and promoted the separation of photo-induced electron-hole pairs. The rGO@g-C3N4/TNAs photoelectrodes exhibited higher photo-electrochemical properties and photocatalytic activity. The removal rate of TC by rGO@g-C3N4/TNAs photoelectrodes could reach 90% under 120 min photo-degradation and reaction kinetic constant was 2.38 times that of TNAs photoelectrodes. The active radicals capture and ESR experiments results showed that O2- radical and OH radical played the major role in photocatalytic degradation of TC. The possible photocatalytic mechanism of rGO@g-C3N4/TNAs photoelectrodes was presented.

Sesquiterpenes and Cyclodepsipeptides from Marine-Derived Fungus Trichoderma longibrachiatum and Their Antagonistic Activities against Soil-borne Pathogens.

Soil-borne pathogens, including phytopathogenic fungi and root-knot nematodes, could synergistically invade vegetable roots and result in serious economic losses. The genus of Trichoderma has been proven to be a promising reservoir of biocontrol agents in agriculture. In this study, the search for antagonistic metabolites from a marine-derived fungus, Trichoderma longibrachiatum, obtained two structural series of sesquiterpenes 1-6 and cyclodepsipeptides 7-9. Notably, the novel 1 was a rare norsesquiterpene characterized by an unprecedented tricyclic-6/5/5-[4.3.1.01,6]-decane skeleton. Their structures were elucidated by extensive spectroscopic analyses, while the absolute configuration of novel 1 was determined by the comparison of experimental and calculated ECD spectra. The novel 1 and known 2 and 3 showed significant antifungal activities against Colletotrichum lagrnarium with MIC values of 8, 16, and 16 µg/mL respectively, even better than those of the commonly used synthetic fungicide carbendazim with 32 µg/mL. They also exhibited antifungal potential against carbendazim-resistant Botrytis cinerea. Cyclodepsipeptides 7-9 showed moderate nematicidal activities against the southern root-knot nematode (Meloidogyne incognita). This study constitutes the first report on the antagonistic effects of metabolites from T. Longibrachiatum against soil-borne pathogens, also highlighting the integrated antagonistic potential of marine-derived T. Longibrachiatum as a biocontrol agent.

Identification and expression of main genes involved in non-target site resistance mechanisms to fenoxaprop-p-ethyl in Beckmannia syzigachne.

BACKGROUND: Non-target-site resistance (NTSR) to herbicides is a serious threat to global agriculture. Although metabolic resistance is the dominant mechanism of NTSR, the molecular mechanisms are not yet well-characterized. This study aimed to uncover the likely metabolism-related genes in Beckmannia syzigachne (American sloughgrass) resistant to fenoxaprop-p-ethyl. RESULTS: Ultra-performance liquid chromatography - tandem mass spectrometry experiments showed that the resistant American sloughgrass biotype (R, SD-04-SS) showed enhanced degradation of this herbicide compared to the susceptible biotype (S, SD-12). R and S biotype were harvested at 24 h after fenoxaprop-p-ethyl treatment to conduct RNA sequencing (RNA-Seq) analysis to investigate the likely fenoxaprop-p-ethyl metabolic genes. The RNA-Seq libraries yield 417 969 980 clean reads. The de novo assembly generated 115 112 unigenes, of which 57 906 unigenes were annotated. Finally, we identified 273 cytochrome P450s, 178 oxidases, 47 glutathione S-transferases (GSTs), 166 glucosyltransferases (GTs) and 180 ABC transporter genes to determine the likely fenoxaprop-p-ethyl metabolism-related genes in R biotype. Twelve overlapping up-regulated genes in the R biotype (fenoxaprop-p-ethyl-treated R/non-treated R, fenoxaprop-p-ethyl-treated R/fenoxaprop-p-ethyl-treated S) were identified by RNA-Seq and the results were validated using qRT-PCR. Ten were identified as fenoxaprop-p-ethyl metabolism-related genes, including three P450s (homologous to CYP71D7, CYP99A2 and CYP71D10), one GST (homologous to GSTF1), two GTs (homologous to UGT90A1 and UGT83A1) and four oxidase genes. CONCLUSION: This work demonstrates that the NTSR mechanism by means of enhanced detoxification of fenoxaprop-p-ethyl in American sloughgrass is very likely driven by herbicide metabolism related genes. The RNA-Seq data presented here provide a valuable resource for understanding the molecular mechanism of NTSR in American sloughgrass. © 2020 Society of Chemical Industry.

Effects of PEDOT:PSS:GO composite hole transport layer on the luminescence of perovskite light-emitting diodes.

Perovskite light-emitting diodes (PeLEDs) employing CH3NH3PbBr3 as the emission layer (EML) and graphene oxide (GO) doped PEDOT:PSS as the hole transport layer (HTL) were prepared and characterized. GO doped in PEDOT:PSS can lead to the increased work function of HTL and lower the hole injection barrier at the HTL/CH3NH3PbBr3 interface, which facilitates the hole injection. Meanwhile, the optimized GO amount in PEDOT:PSS can help to reduce the quenching of luminescence occurring at the interface between HTL and perovskite. The luminance and current efficiency reach the maximum values of 3302 cd m-2 and 1.92 cd A-1 in PeLED with an optimized GO ratio (0.3), which increase by 43.3% and 73.0% in comparison with the undoped device, respectively. The enhanced luminescence of PeLEDs was caused by the combined effects of enhanced hole injection efficiency and the suppressed exciton quenching occurring at the HTL/EML interface. These results indicate that the introduction of traditional two-dimensional materials is a reasonable method for designing the structure of PeLEDs.

Characterization and bioactive potentials of secondary metabolites from Fusarium chlamydosporum.

A search for bioactive secondary metabolites from the endophytic fungus Fusarium chlamydosporum, isolated from the root of Suaeda glauca, led to the isolation of three indole derivatives (1-3), three cyclohexadepsipeptides (4-6), and four pyrones (7-10). The structures of new (1) and known compounds (2-10) were elucidated on the basis of extensive spectroscopic analysis. All these compounds were evaluated for phytotoxic, antimicrobial activities, and brine shrimp lethality. Compound 1 showed significant phytotoxic activity against the radicle growth of Echinochloa crusgalli, even better than the positive control of 2,4-D. Cyclohexadepsipeptides (4-6) and pyrones (7-10) exhibited brine shrimp lethality, especially 4 and 7 with the LD50 values of 2.78 and 7.40 µg mL-1, respectively, better than the positive control.

Herbicidal Polyketides and Diketopiperazine Derivatives from Penicillium viridicatum.

Herbicidal activity-guided isolation from the fermentation extract of Penicillium viridicatum had obtained two herbicidal series of polyketides (1-7) and diketopiperazine derivatives (8-11), especially including three novel polyketides (1-3). The structures and absolute configurations of new polyketides 1-3 were elucidated by extensive spectroscopic analyses, as well as comparisons between measured and calculated ECD spectra. Novel polyketides 1-3 and known 4, all bearing the heptaketide skeleton with a trans-fused decalin ring of 8-CH3 substitution, could significantly inhibit the radicle growth of Echinochloa crusgalli seedlings with a dose-dependent relationship. Especially at the concentration of 10 µg/mL, 1-4 exhibited the inhibition rates with 81.5% ± 2.0, 76.4% ± 0.8, 79.6% ± 1.1, and 80.0 ± 1.8%, respectively, even better than the commonly used synthetic herbicide of acetochlor with 76.1 ± 1.4%. Further greenhouse bioassay revealed that 4 showed pre-emergence herbicidal activity against E. crusgalli with the fresh-weight inhibition rate of 74.1% at a dosage of 400 g ai/ha, also better than acetochlor, while the other isolated metabolites (5-11) exhibited moderate herbicidal activities. The structure-activity differences of isolated polyketides indicated that the heptaketide skeleton, characterized by a trans-fused decalin ring with 8-CH3 substitution, should be the key factor of their herbicidal activities, which could give new insights for the bioherbicide developments.

Distribution and elimination of quinocetone and its major metabolites in Cherry Valley ducks.

We examined the tissue distribution and elimination of quinocetone (QCT) and its major metabolites 1-desoxyquinocetone (1-DQCT), di-desoxyquinocetone (BDQCT), and 3-methyl-quinoxaline-2-carboxylic (MQCA) in ducks. The analytes were simultaneously quantitated using a UPLC-MS/MS method after oral administration of QCT at 100 mg·kg-1 day-1 for 7 days. We found that QCT and its major metabolites were widely distributed in duck tissues. The concentrations indicated that the primary compound in the liver, kidney, and heart was MQCA and the primary compound in the stomach, intestine, spleen, and lung was QCT. We also identified that MQCA was the most appropriate compound for QCT residue monitoring. The liver and kidney are the primary QCT target organs in ducks, and this study provides clear monitoring tools and important data to evaluate its safety.

Improved Efficiency of Perovskite Light-Emitting Diodes Using a Three-Step Spin-Coated CH3NH3PbBr3 Emitter and a PEDOT:PSS/MoO3-Ammonia Composite Hole Transport Layer.

High efficiency perovskite light-emitting diodes (PeLEDs) using PEDOT:PSS/MoO3-ammonia composite hole transport layers (HTLs) with different MoO3-ammonia ratios were prepared and characterized. For PeLEDs with one-step spin-coated CH3NH3PbBr3 emitter, an optimal MoO3-ammonia volume ratio (0.02) in PEDOT:PSS/MoO3-ammonia composite HTL presented a maximum luminance of 1082 cd/m2 and maximum current efficiency of 0.7 cd/A, which are 82% and 94% higher than those of the control device using pure PEDOT:PSS HTL respectively. It can be explained by that the optimized amount of MoO3-ammonia in the composite HTLs cannot only facilitate hole injection into CH3NH3PbBr3 through reducing the contact barrier, but also suppress the exciton quenching at the HTL/CH3NH3PbBr3 interface. Three-step spin coating method was further used to obtain uniform and dense CH3NH3PbBr3 films, which lead to a maximum luminance of 5044 cd/m2 and maximum current efficiency of 3.12 cd/A, showing enhancement of 750% and 767% compared with the control device respectively. The significantly improved efficiency of PeLEDs using three-step spin-coated CH3NH3PbBr3 film and an optimum PEDOT:PSS/MoO3-ammonia composite HTL can be explained by the enhanced carrier recombination through better hole injection and film morphology optimization, as well as the reduced exciton quenching at HTL/CH3NH3PbBr3 interface. These results present a promising strategy for the device engineering of high efficiency PeLEDs.

Unusual and Highly Bioactive Sesterterpenes Synthesized by Pleurotus ostreatus during Coculture with Trametes robiniophila Murr.

Candida albicans and Cryptococcus neoformans, human-pathogenic fungi found worldwide, are receiving increasing attention due to high morbidity and mortality in immunocompromised patients. In the present work, 110 fungus pairs were constructed by coculturing 16 wood-decaying basidiomycetes, among which coculture of Trametes robiniophila Murr and Pleurotus ostreatus was found to strongly inhibit pathogenic fungi through bioactivity-guided assays. A combination of metabolomics and molecular network analysis revealed that 44 features were either newly synthesized or produced at high levels in this coculture system and that 6 of the features that belonged to a family of novel and unusual linear sesterterpenes contributed to high activity with MICs of 1 to 32 µg/ml against pathogenic fungi. Furthermore, dynamic 13C-labeling analysis revealed an association between induced features and the corresponding fungi. Unusual sesterterpenes were 13C labeled only in P. ostreatus in a time course after stimulation by the coculture, suggesting that these sesterterpenes were synthesized by P. ostreatus instead of T. robiniophila Murr. Sesterterpene compounds 1 to 3 were renamed postrediene A to C. Real-time reverse transcription-quantitative PCR (RT-qPCR) analysis revealed that transcriptional levels of three genes encoding terpene synthase, farnesyl-diphosphate farnesyltransferase, and oxidase were found to be 8.2-fold, 88.7-fold, and 21.6-fold higher, respectively, in the coculture than in the monoculture, indicating that biosynthetic gene cluster 10 was most likely responsible for the synthesis of these sesterterpenes. A putative biosynthetic pathway of postrediene A to postrediene C was then proposed based on structures of sesterterpenes and molecular network analysis.IMPORTANCE A number of gene clusters involved in biosynthesis of secondary metabolites are presumably silent or expressed at low levels under conditions of standard laboratory cultivation, resulting in a large gap between the pool of discovered metabolites and genome capability. This work mimicked naturally occurring competition by construction of an artificial coculture of basidiomycete fungi for the identification of secondary metabolites with novel scaffolds and excellent bioactivity. Unusual linear sesterterpenes of postrediene A to C synthesized by P. ostreatus not only were promising lead drugs against human-pathogenic fungi but also highlighted a distinct pathway for sesterterpene biosynthesis in basidiomycetes. The current work provides an important basis for uncovering novel gene functions involved in sesterterpene synthesis and for gaining insights into the mechanism of silent gene activation in fungal defense.

Effects of Charge Transport Materials on Blue Fluorescent Organic Light-Emitting Diodes with a Host-Dopant System.

High efficiency blue fluorescent organic light-emitting diodes (OLEDs), based on 1,3-bis(carbazol-9-yl)benzene (mCP) doped with 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi), were fabricated using four different hole transport layers (HTLs) and two different electron transport layers (ETLs). Fixing the electron transport material TPBi, four hole transport materials, including 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4'-diamine(NPB), 4,4'-Bis(N-carbazolyl)-1,1,-biphenyl (CBP) and molybdenum trioxide (MoO3), were selected to be HTLs, and the blue OLED with TAPC HTL exhibited a maximum luminance of 2955 cd/m2 and current efficiency (CE) of 5.75 cd/A at 50 mA/cm2, which are 68% and 62% higher, respectively, than those of the minimum values found in the device with MoO3 HTL. Fixing the hole transport material TAPC, the replacement of TPBi ETL with Bphen ETL can further improve the performance of the device, in which the maximum luminance can reach 3640 cd/m2 at 50 mA/cm2, which is 23% higher than that of the TPBi device. Furthermore, the lifetime of the device is also optimized by the change of ETL. These results indicate that the carrier mobility of transport materials and energy level alignment of different functional layers play important roles in the performance of the blue OLEDs. The findings suggest that selecting well-matched electron and hole transport materials is essential and beneficial for the device engineering of high-efficiency blue OLEDs.

Cyclodepsipeptides and Sesquiterpenes from Marine-Derived Fungus Trichothecium roseum and Their Biological Functions.

On the basis of the 'one strain, many compounds' (OSMAC) strategy, chemical investigation of the marine-derived fungus Trichothecium roseum resulted in the isolation of trichomide cyclodepsipeptides (compounds 1⁻4) from PDB medium, and destruxin cyclodepsipeptides (compounds 5⁻7) and cyclonerodiol sesquiterpenes (compounds 8⁻10) from rice medium. The structures and absolute configurations of novel (compounds 1, 8, and 9) and known compounds were elucidated by extensive spectroscopic analyses, X-ray crystallographic analysis, and ECD calculations. All isolated compounds were evaluated for cytotoxic, nematicidal, and antifungal activities, as well as brine shrimp lethality. The novel compound 1 exhibited significant cytotoxic activities against the human cancer cell lines MCF-7, SW480, and HL-60, with IC50 values of 0.079, 0.107, and 0.149 µM, respectively. In addition, it also showed significant brine shrimp lethality, with an LD50 value of 0.48 µM, and moderate nematicidal activity against Heterodera avenae, with an LC50 value of 94.9 µg/mL. This study constitutes the first report on the cytotoxic and nematicidal potential of trichomide cyclodepsipeptides.

Notopterygium incisum extract and associated secondary metabolites inhibit apple fruit fungal pathogens.

In the search for antifungal lead compounds from natural resources, Notopterygium incisum, a medicine plant only distributed in China, showed antifungal potential against apple fruit pathogens. Based on the bioassay-guided isolation, chromatography fraction 6 of the ethyl acetate partition exhibited significant in vitro and in vivo antifungal activities against apple fruit pathogens. Furthermore, nine antifungal secondary metabolites, including five linear furocoumarins (1-5), two phenylethyl esters (6-7), one falcarindiol (8), and one sesquiterpenoid (9), were isolated and elucidated from fraction 6. Compound 5 is a new metabolite, and 9 isolated from the genus Notopterygium for the first time. The purified compounds (1-9) were firstly reported to exhibit antifungal activities against apple fruit pathogens of Colletotrichum gloeosporioides and Botryosphaeria dothidea with the MIC values ranging from 8 to 250 mg L-1, especially 8 of 16 and 8 mg L-1, respectively. Moreover, 8 could inhibit the spore germination and new sporulation of B. dothidea, as well as enhance the membrane permeabilization of B. dothidea spores. This was the first investigation for the antifungal components against apple fruit pathogens from Notopterygium incisum, which has great potential to be developed into bio-fungicides.

Production of 3-hydroxypropionic acid in engineered Methylobacterium extorquens AM1 and its reassimilation through a reductive route.

BACKGROUND: 3-Hydroxypropionic acid (3-HP) is an important platform chemical, serving as a precursor for a wide range of industrial applications such as the production of acrylic acid and 1,3-propanediol. Although Escherichia coli or Saccharomyces cerevisiae are the primary industrial microbes for the production of 3-HP, alternative engineered hosts have the potential to generate 3-HP from other carbon feedstocks. Methylobacterium extorquens AM1, a facultative methylotrophic α-proteobacterium, is a model system for assessing the possibility of generating 3-HP from one-carbon feedstock methanol. RESULTS: Here we constructed a malonyl-CoA pathway by heterologously overexpressing the mcr gene to convert methanol into 3-HP in M. extorquens AM1. The engineered strains demonstrated 3-HP production with initial titer of 6.8 mg/l in shake flask cultivation, which was further improved to 69.8 mg/l by increasing the strength of promoter and mcr gene copy number. In vivo metabolic analysis showed a significant decrease of the acetyl-CoA pool size in the strain with the highest 3-HP titer, suggesting the supply of acetyl-CoA is a potential bottleneck for further improvement. Notably, 3-HP was rapidly degraded after the transition from exponential phase to stationary phase. Metabolomics analysis showed the accumulation of intracellular 3-hydroxypropionyl-CoA at stationary phase with the addition of 3-HP into the cultured medium, indicating 3-HP was first converted to its CoA derivatives. In vitro enzymatic assay and ß-alanine pathway dependent 13C-labeling further demonstrated that a reductive route sequentially converted 3-HP-CoA to acrylyl-CoA and propionyl-CoA, with the latter being reassimilated into the ethylmalonyl-CoA pathway. The deletion of the gene META1_4251 encoding a putative acrylyl-CoA reductase led to reduced degradation rate of 3-HP in late stationary phase. CONCLUSIONS: We demonstrated the feasibility of constructing the malonyl-CoA pathway in M. extorquens AM1 to generate 3-HP. Furthermore, we showed that a reductive route coupled with the ethylmalonyl-CoA pathway was the major channel responsible for degradation of the 3-HP during the growth transition. Engineered M. extorquens AM1 represents a good platform for 3-HP production from methanol.