Flexible solar cells based on foldable silicon wafers with blunted edges.

Flexible solar cells have a lot of market potential for application in photovoltaics integrated into buildings and wearable electronics because they are lightweight, shockproof and self-powered. Silicon solar cells have been successfully used in large power plants. However, despite the efforts made for more than 50 years, there has been no notable progress in the development of flexible silicon solar cells because of their rigidity1-4. Here we provide a strategy for fabricating large-scale, foldable silicon wafers and manufacturing flexible solar cells. A textured crystalline silicon wafer always starts to crack at the sharp channels between surface pyramids in the marginal region of the wafer. This fact enabled us to improve the flexibility of silicon wafers by blunting the pyramidal structure in the marginal regions. This edge-blunting technique enables commercial production of large-scale (>240 cm2), high-efficiency (>24%) silicon solar cells that can be rolled similarly to a sheet of paper. The cells retain 100% of their power conversion efficiency after 1,000 side-to-side bending cycles. After being assembled into large (>10,000 cm2) flexible modules, these cells retain 99.62% of their power after thermal cycling between -70 °C and 85 °C for 120 h. Furthermore, they retain 96.03% of their power after 20 min of exposure to air flow when attached to a soft gasbag, which models wind blowing during a violent storm.

Involvement of a rice mutation in storage protein biogenesis in endosperm and its genomic location.

MAIN CONCLUSION: A mutation was first found to cause the great generation of glutelin precursors (proglutelins) in rice (Oryza sativa L.) endosperm, and thus referred to as GPGG1. The GPGG1 was involved in synthesis and compartmentation of storage proteins. The PPR-like gene in GPGG1-mapped region was determined as its candidate gene. In the wild type rice, glutelins and prolamins are synthesized on respective subdomains of rough endoplasmic reticulum (ER) and intracellularly compartmentalized into different storage protein bodies. In this study, a storage protein mutant was obtained and characterized by the great generation of proglutelins combining with the lacking of 13 kD prolamins. A dominant genic-mutation, referred to as GPGG1, was clarified to result in the proteinous alteration. Novel saccular composite-ER was shown to act in the synthesis of proglutelins and 14 kD prolamins in the mutant. Additionally, a series of organelles including newly occurring several compartments were shown to function in the transfer, trans-plasmalemmal transport, delivery, deposition and degradation of storage proteins in the mutant. The GPGG1 gene was mapped to a 67.256 kb region of chromosome 12, the pentatricopeptide repeat (PPR)-like gene in this region was detected to contain mutational sites.

Spectral-Spatial Feature Fusion for Hyperspectral Anomaly Detection.

Hyperspectral anomaly detection is used to recognize unusual patterns or anomalies in hyperspectral data. Currently, many spectral-spatial detection methods have been proposed with a cascaded manner; however, they often neglect the complementary characteristics between the spectral and spatial dimensions, which easily leads to yield high false alarm rate. To alleviate this issue, a spectral-spatial information fusion (SSIF) method is designed for hyperspectral anomaly detection. First, an isolation forest is exploited to obtain spectral anomaly map, in which the object-level feature is constructed with an entropy rate segmentation algorithm. Then, a local spatial saliency detection scheme is proposed to produce the spatial anomaly result. Finally, the spectral and spatial anomaly scores are integrated together followed by a domain transform recursive filtering to generate the final detection result. Experiments on five hyperspectral datasets covering ocean and airport scenes prove that the proposed SSIF produces superior detection results over other state-of-the-art detection techniques.

Fluorescence sensing and glycosidase inhibition effect of multivalent glycosidase inhibitors based on Naphthalimide-deoxynojirimycin conjugates.

Synthetic glycoconjugates as chemical probes have been widely developed for the detection of glycosidase enzymes. However, the binding interactions between iminosugar derivatives and glycosidases were limited, especially for the binding interactions between multivalent glycosidase inhibitors and α-glycosidases. In this paper, three naphthalimide-DNJ conjugates were synthesized. Furthermore, the binding interactions and glycosidase inhibition effects of them were investigated. It was found that the strong binding interactions of multivalent glycosidase inhibitors with enzymes were related to the efficient inhibitory activity against glycosidase. Moreover, the lengths of the chain between DNJ moieties and the triazole ring for the naphthalimide-DNJ conjugates influenced the self-assembly properties, binding interactions and glycosidase inhibition activities with multisource glycosidases. Compound 13 with six carbons between the DNJ moiety and triazole ring showed the stronger binding interactions and better glycosidase inhibition activities against α-mannosidase (jack bean) and α-glucosidase (aspergillus niger). In addition, compound 13 showed an effective PBG inhibition effect in mice with 51.18 % decrease in blood glucose at 30 min. This result opens a way for detection of multivalent glycosidase inhibition effect by a fluorescent sensing method.

Single-Crystal Nano-Subunits Assembled Accordion-Shape WNb2 O8 Framework with High Ionic/Electronic Conductivities towards Li-Ion Capacitors.

Recently, Li-ion capacitors (LICs) have drawn tremendous attention due to their high energy/power density along with long cycle life. Nevertheless, the slow kinetics and stability of the involved anodes as bottleneck barriers always result in the modest properties of devices. The exploration of advanced anodes with both high ionic and electronic conductivities as well as structural stability thus becomes more significant for practical applications of LICs. Herein, a single-crystal nano-subunits assembled hierarchical accordion-shape WNb2 O8 micro-/nano framework is first designed via a one-step scalable strategy with the multi-layered Nb2 CTx as a precursor. The underlying solid solution Li-storage mechanism of the WNb2 O8 just with a volumetric expansion of ≈1.5% is proposed with in situ analysis. Benefiting from congenitally crystallographic merits, single-crystalline characteristic, and open accordion-like architecture, the resultant WNb2 O8 as a robust anode platform is endowed with fast electron/ion transport capability and multi-electron redox contributions from W/Nb, and accordingly, delivers a reversible capacity of ≈135.5 mAh g-1 at a high rate of 2.0 A g-1 . The WNb2 O8 assembled LICs exhibit an energy density of ≈33.0 Wh kg-1 at 9 kW kg-1 , coupled with remarkable electrochemical stability. The work provides meaningful insights into the rational design and construction of advanced bimetallic niobium oxides for next-generation LICs.

Runoff control simulation and comprehensive benefit evaluation of low-impact development strategies in a typical cold climate area.

With the acceleration of urbanization, the proportion of surface imperviousness is increasing continuously in cities, resulting in frequent waterlogging disasters. In this context, storm water management, based on the low-impact development (LID) concept, offers an effective measure for the management of urban storm waters. First, the storm water management model (SWMM) was built for a typical cold climate city (Changchun) in China. Next, the two-stage calibrated model was employed to explore the surface runoff and storm sewer control effects of four LID combination plans. Finally, these plans were put through a "cost-benefit" evaluation through an analytic hierarchy process. According to the results, after using four LID plans, the reduction rates of peak runoff exceeded 40% and the problem of overflow load of the storm sewage was significantly mitigated. The infiltration-oriented Plan I proved to be the optimal plan, with the lowest proportions of the overflow nodes and full-load pipe sections in each return period, as well as with maximum overall performance. This study offers technical and conformed methodological support to cold cities for the prevention and control of waterlogging disasters and recycling of rainwater resources.

Thermophilic Nucleic Acid Polymerases and Their Application in Xenobiology.

Thermophilic nucleic acid polymerases, isolated from organisms that thrive in extremely hot environments, possess great DNA/RNA synthesis activities under high temperatures. These enzymes play indispensable roles in central life activities involved in DNA replication and repair, as well as RNA transcription, and have already been widely used in bioengineering, biotechnology, and biomedicine. Xeno nucleic acids (XNAs), which are analogs of DNA/RNA with unnatural moieties, have been developed as new carriers of genetic information in the past decades, which contributed to the fast development of a field called xenobiology. The broad application of these XNA molecules in the production of novel drugs, materials, and catalysts greatly relies on the capability of enzymatic synthesis, reverse transcription, and amplification of them, which have been partially achieved with natural or artificially tailored thermophilic nucleic acid polymerases. In this review, we first systematically summarize representative thermophilic and hyperthermophilic polymerases that have been extensively studied and utilized, followed by the introduction of methods and approaches in the engineering of these polymerases for the efficient synthesis, reverse transcription, and amplification of XNAs. The application of XNAs facilitated by these polymerases and their mutants is then discussed. In the end, a perspective for the future direction of further development and application of unnatural nucleic acid polymerases is provided.

Identification of Heavy Metals and Organic Micropollutants in Drinking Water Sources in Typical Villages and Towns in Northeast China.

This study identified and detected the existence of major pollutants in northeast China. As an alpine region and an agricultural base, this region has representative significance in pollution research. We selected 56 samples from drinking water sources of typical villages and towns, focusing on the analysis of heavy metals and organic micropollutants in northeast China. The analysis results showed that Fe and Mn were the main metal elements exceeding the standard. The exceeding rates were 17.9% and 19.6%. Experiments showed that there were 19 kinds of pesticides, 6 kinds of OPEs, 2 kinds of PAEs, 22 kinds of PPCPs. The detection rate of these 49 kinds of organic micro-pollutants were 1.79~82.14%. The characteristics of organic pollution were extensive and varied. Many underground water samples had high level of micropollutants. The water quality parameters of drinking water sources in villages and towns showed close relation to local geological conditions and agricultural activities. Actions must be taken to control these parameters from the source of pollution.

A high activity zinc transporter OsZIP9 mediates zinc uptake in rice.

Zinc (Zn) is an essential micronutrient for most organisms including humans, and Zn deficiency is widespread in human populations, particularly in underdeveloped regions. Cereals such as rice (Oryza sativa) are the major dietary source of Zn for most people. However, the molecular mechanism underlying Zn uptake in rice is still not fully understood. Here, we report that a member of the ZIP (ZRT, IRT-like protein) family, OsZIP9, contributes to Zn uptake in rice. It was expressed in the epidermal and exodermal cells of lateral roots, localized in the plasma membrane and induced during Zn deficiency. Yeast-expressed OsZIP9 showed much higher Zn influx transport activity than other rice ZIP proteins in a wide range of Zn concentrations. OsZIP9 knockout rice plants showed a significant reduction in growth at low Zn concentrations, but could be rescued by a high Zn supply. Compared with the wild type, accumulation of Zn in root, shoot and grain was much lower in knockout lines, particularly with a low supply of Zn under both hydroponic and paddy soil conditions. OsZIP9 also showed Co uptake activity. Natural variation of OsZIP9 expression level is highly associated with Zn content in milled grain among rice varieties in the germplasm collection. Taken together, these results show that OsZIP9 is an important influx transporter responsible for the take up of Zn and Co from external media into root cells.

Systematic analysis of the lysine malonylome in Sanghuangporus sanghuang.

BACKGROUND: Sanghuangporus sanghuang is a well-known traditional medicinal mushroom associated with mulberry. Despite the properties of this mushroom being known for many years, the regulatory mechanisms of bioactive compound biosynthesis in this medicinal mushroom are still unclear. Lysine malonylation is a posttranslational modification that has many critical functions in various aspects of cell metabolism. However, at present we do not know its role in S. sanghuang. In this study, a global investigation of the lysine malonylome in S. sanghuang was therefore carried out. RESULTS: In total, 714 malonyl modification sites were matched to 255 different proteins. The analysis indicated that malonyl modifications were involved in a wide range of cellular functions and displayed a distinct subcellular localization. Bioinformatics analysis indicated that malonylated proteins were engaged in different metabolic pathways, including glyoxylate and dicarboxylate metabolism, glycolysis/gluconeogenesis, and the tricarboxylic acid (TCA) cycle. Notably, a total of 26 enzymes related to triterpene and polysaccharide biosynthesis were found to be malonylated, indicating an indispensable role of lysine malonylation in bioactive compound biosynthesis in S. sanghuang. CONCLUSIONS: These findings suggest that malonylation is associated with many metabolic pathways, particularly the metabolism of the bioactive compounds triterpene and polysaccharide. This paper represents the first comprehensive survey of malonylation in S. sanghuang and provides important data for further study on the physiological function of lysine malonylation in S. sanghuang and other medicinal mushrooms.

Genome-Wide Association Studies Reveal the Genetic Basis of Ionomic Variation in Rice.

Rice (Oryza sativa) is an important dietary source of both essential micronutrients and toxic trace elements for humans. The genetic basis underlying the variations in the mineral composition, the ionome, in rice remains largely unknown. Here, we describe a comprehensive study of the genetic architecture of the variation in the rice ionome performed using genome-wide association studies (GWAS) of the concentrations of 17 mineral elements in rice grain from a diverse panel of 529 accessions, each genotyped at ∼6.4 million single nucleotide polymorphism loci. We identified 72 loci associated with natural ionomic variations, 32 that are common across locations and 40 that are common within a single location. We identified candidate genes for 42 loci and provide evidence for the causal nature of three genes, the sodium transporter gene Os-HKT1;5 for sodium, Os-MOLYBDATE TRANSPORTER1;1 for molybdenum, and Grain number, plant height, and heading date7 for nitrogen. Comparison of GWAS data from rice versus Arabidopsis (Arabidopsis thaliana) also identified well-known as well as new candidates with potential for further characterization. Our study provides crucial insights into the genetic basis of ionomic variations in rice and serves as an important foundation for further studies on the genetic and molecular mechanisms controlling the rice ionome.

A laser-induced graphene electrochemical immunosensor for label-free CEA monitoring in serum.

The cost-effective construction of self-designed conductive graphene patterns is crucial to the fabrication of graphene-based electrochemical devices. Here, a label-free carcinoembryonic antigen (CEA) electrochemical immunosensor is developed based on the surface engineering of a laser-induced graphene (LIG)/Au electrode. The LIG electrode was produced with a smart and inexpensive 450 nm semiconductor laser through three electrode patterns under ambient conditions. Then the LIG/Au electrode was organized by conformal anchoring of Au nanoparticles (NPs) on the LIG work area using chloroauric acid as the precursor. Good electrochemical activity with improved conductivity of the LIG/Au electrode was obtained under optimized conditions of laser intensity, carving depth, and chlorogenic acid dosage, to name a few. The LIG/Au electrode was carbonylated based on Au-S∼COOH using 11-mercaptoundecanoic acid (MUA). The antibody was covalently bound on the work area to form a label-free immunosensor. The constructed immunosensor shows high sensitivity with a good response in the range of low concentrations from 0.01 to 100 ng mL-1, low detection limit (5.0 pg mL-1), high selectivity compared with some possible interference, and can be applied in a bovine serum solution without the need of sample labeling and pretreatment. Moreover, the immunosensor is mechanically flexible with minimal change in signal output after bending at different angles. It shows an easy and green electrode preparation method that combines 3D porous structures of graphene, uniform immobilization of Au NPs, binder-free, easy covalent binding of an antibody, and good mechanical properties. Hence, the present method has great potential for applications involving electrochemical biosensors.

BcSas2-Mediated Histone H4K16 Acetylation Is Critical for Virulence and Oxidative Stress Response of Botrytis cinerea.

Histone acetyltransferase plays a critical role in transcriptional regulation by increasing accessibility of target genes to transcriptional activators. Botrytis cinerea is an important necrotrophic fungal pathogen with worldwide distribution and a very wide host range, but little is known of how the fungus regulates the transition from saprophytic growth to infectious growth. Here, the function of BcSas2, a histone acetyltransferase of B. cinerea, was investigated. Deletion of the BcSAS2 gene resulted in significantly reduced acetylation levels of histone H4, particularly of H4K16ac. The deletion mutant ΔBcSas2.1 was not only less pathogenic but also more sensitive to oxidative stress than the wild-type strain. RNA-Seq analysis revealed that a total of 13 B. cinerea genes associated with pathogenicity were down-regulated in the ΔBcSas2.1 mutant. Independent knockouts of two of these genes, BcXYGA (xyloglucanase) and BcCAT (catalase), led to dramatically decreased virulence and hypersensitivity to oxidative stress, respectively. Chromatin immunoprecipitation followed by quantitative PCR confirmed that BcSas2 bound directly to the promoter regions of both these pathogenicity-related genes. These observations indicated that BcSas2 regulated the transcription of pathogenicity-related genes by controlling the acetylation level of H4K16, thereby affecting the virulence and oxidative sensitivity of B. cinerea.

Systematic analysis of the lysine succinylome in the model medicinal mushroom Ganoderma lucidum.

BACKGROUND: Ganoderma lucidum, one of the best-known medicinal mushrooms in the world, produces more than 400 different bioactive compounds. However, the regulation of these bioactive compounds biosynthesis is still unclear. Lysine succinylation is a critical post-translational modification and has many important functions in all aspects of eukaryotic and prokaryotic cells. Although it has been studied for a long time, its function is still unclear in G. lucidum. In this study, a global investigation was carried out on the succinylome in G. lucidum. RESULTS: In total, 382 modified proteins which contain 742 lysine succinylated sites were obtained. The proteomics data are available through ProteomeXchange with the dataset accession number PXD013954. Bioinformatics analysis revealed that the succinylated proteins were distributed in various cellular biological processes and participated in a great variety of metabolic pathways including carbon metabolism and biosynthesis of secondary metabolites. Notably, a total of 47 enzymes associated with biosynthesis of triterpenoids and polysaccharides were found to be succinylated. Furthermore, two succinylated sites K90 and K106 were found in the conserved Fve region of immunomodulatory protein LZ8. These observations show that lysine succinylation plays an indispensable role in metabolic regulation of bioactive compounds in G. lucidum. CONCLUSIONS: These findings indicate that lysine succinylation is related to many metabolic pathways, especially pharmacologically bioactive compounds metabolism. This study provides the first global investigation of lysine succinylation in G. lucidum and the succinylome dataset provided in this study serves as a resource to further explore the physiological roles of these modifications in secondary metabolism.

Systematic analysis of the lysine malonylome in common wheat.

BACKGROUND: Protein lysine malonylation, a newly discovered post-translational modification (PTM), plays an important role in diverse metabolic processes in both eukaryotes and prokaryotes. Common wheat is a major global cereal crop. However, the functions of lysine malonylation are relatively unknown in this crop. Here, a global analysis of lysine malonylation was performed in wheat. RESULTS: In total, 342 lysine malonylated sites were identified in 233 proteins. Bioinformatics analysis showed that the frequency of arginine (R) in position + 1 was highest, and a modification motif, KmaR, was identified. The malonylated proteins were located in multiple subcellular compartments, especially in the cytosol (45%) and chloroplast (30%). The identified proteins were found to be involved in diverse pathways, such as carbon metabolism, the Calvin cycle, and the biosynthesis of amino acids, suggesting an important role for lysine malonylation in these processes. Protein interaction network analysis revealed eight highly interconnected clusters of malonylated proteins, and 137 malonylated proteins were mapped to the protein network database. Moreover, five proteins were simultaneously modified by lysine malonylation, acetylation and succinylation, suggesting that these three PTMs may coordinately regulate the function of many proteins in common wheat. CONCLUSIONS: Our results suggest that lysine malonylation is involved in a variety of biological processes, especially carbon fixation in photosynthetic organisms. These data represent the first report of the lysine malonylome in common wheat and provide an important dataset for further exploring the physiological role of lysine malonylation in wheat and likely all plants.

Comparative transcriptome analysis reveals multiple functions for Mhy1p in lipid biosynthesis in the oleaginous yeast Yarrowia lipolytica.

Yarrowia lipolytica is considered as a promising microbial cell factory for bio-oil production due to its ability to accumulate a large amount of lipid. However, the regulation of lipid metabolism in this oleaginous yeast is elusive. In this study, the MHY1 gene was disrupted, and 43.1% (w/w) intracellular oil based on cell dry weight was obtained from the disruptant M-MHY1, while only 30.2% (w/w) lipid based on cell dry weight was obtained from the reference strain. RNA-seq was then performed to analyze transcriptional changes during lipid biosynthesis after MHY1 gene inactivation. The expression of 1597 genes, accounting for 24.7% of annotated Y. lipolytica genes, changed significantly in the disruptant M-MHY1 during lipid biosynthesis. Differential gene expression analysis indicated that Mhy1p performs multiple functions and participates in a wide variety of biological processes, including lipid, amino acid and nitrogen metabolism. Notably, data analysis revealed increased carbon flux through lipid biosynthesis following MHY1 gene inactivation, accompanied by decreased carbon flux through amino acid biosynthesis. Moreover, Mhy1p regulates the cell cycle, and the cell cycle rate was enhanced in the disruptant M-MHY1. These results suggest that Mhy1p plays critical regulatory roles in diverse aspects of various biological processes, especially in lipid biosynthesis, amino acid and nitrogen metabolism and cell cycle. Our dataset appears to elucidate the crucial role of Mhy1p in lipid biosynthesis and serves as a resource for exploring physiological dimorphic growth in Y. lipolytica.

Reversible acetylation on Lys501 regulates the activity of RNase II.

RNase II, a 3' to 5' processive exoribonuclease, is the major hydrolytic enzyme in Escherichia coli accounting for ∼90% of the total activity. Despite its importance, little is actually known about regulation of this enzyme. We show here that one residue, Lys501, is acetylated in RNase II. This modification, reversibly controlled by the acetyltransferase Pka, and the deacetylase CobB, affects binding of the substrate and thus decreases the catalytic activity of RNase II. As a consequence, the steady-state level of target RNAs of RNase II may be altered in the cells. We also find that under conditions of slowed growth, the acetylation level of RNase II is elevated and the activity of RNase II decreases, emphasizing the importance of this regulatory process. These findings indicate that acetylation can regulate the activity of a bacterial ribonuclease.

Simultaneous production of single cell oil and fumaric acid by a newly isolated yeast Aureobasidium pullulans var. aubasidani DH177.

Microbial oils can be used for biodiesel production and fumaric acid (FA) is widely used in the food and chemical industries. In this study, the production of lipids and FA by Aureobasidium pullulans var. aubasidani DH177 was investigated. A high initial carbon/nitrogen ratio in the medium promoted the accumulation of lipids and FA. When the medium contained 12.0% glucose and 0.2% NH4NO3, the yeast strain DH177 accumulated 64.7% (w/w) oil in its cells, 22.4 g/l cell biomass and 32.3 g/l FA in a 5-L batch fermentation. The maximum yields of oil and FA were 0.12 g/g and 0.27 g/g of consumed sugar, respectively. The compositions of the produced fatty acids were C14:0 (0.6%), C16:0 (24.9%), C16:1 (4.4%), C18:0 (2.1%), C18:1 (57.6%), and C18:2 (10.2%). Biodiesel obtained from the extracted oil burned well. This study provides the pioneering utilization of the yeast strain DH177 for the integrated production of oil and FA.

Global analysis of protein lysine succinylation profiles in common wheat.

BACKGROUND: Protein lysine succinylation is an important post-translational modification and plays a critical regulatory role in almost every aspects of cell metabolism in both eukaryotes and prokaryotes. Common wheat is one of the major global cereal crops. However, to date, little is known about the functions of lysine succinylation in this plant. Here, we performed a global analysis of lysine succinylation in wheat and examined its overlap with lysine acetylation. RESULTS: In total, 330 lysine succinylated modification sites were identified in 173 proteins. Bioinformatics analysis showed that the modified proteins are distributed in multiple subcellular compartments and are involved in a wide variety of biological processes such as photosynthesis and the Calvin-Benson cycle, suggesting an important role for lysine succinylation in these processes. Five putative succinylation motifs were identified. A protein interaction network analysis revealed that diverse interactions are modulated by protein succinylation. Moreover, 21 succinyl-lysine sites were found to be acetylated at the same position, and 33 proteins were modified by both acetylation and succinylation, suggesting an extensive overlap between succinylation and acetylation in common wheat. Comparative analysis indicated that lysine succinylation is conserved between common wheat and Brachypodium distachyon. CONCLUSIONS: These results suggest that lysine succinylation is involved in diverse biological processes, especially in photosynthesis and carbon fixation. This systematic analysis represents the first global analysis of lysine succinylation in common wheat and provides an important resource for exploring the physiological role of lysine succinylation in this cereal crop and likely in all plants.

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.