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[Display omitted] • Composites of polyimide derived carbon nanofibers and MnO 2 nanosheets are reported. • The structure effectively suppresses Jahn-Teller effect and promotes fast Zn2+ ion diffusion. • The combination of delicate fiber and salty ice electrolyte enables excellent electrochemical performance. • A potential low temperature electrolyte is demonstrated. • The cell can work at a low temperature of −20 °C and 500 cycles is achieved under 0 °C. Mn-based aqueous zinc-ion batteries are potential candidates for energy storage owing to the low cost, high efficiency, and safety. Nevertheless, the Jahn–Teller effect induces Mn2+ dissolution and irreversible phase changes, seriously deteriorating the cycling life. Herein, the facile construction and low temperature performance of the core–shell composites of polyimide derived nitrogen-doped carbon nanofibers and δ-MnO 2 (δ-MnO 2 -CNFs) are reported, where ultrafine MnO 2 arrays are tightly anchored on carbon nanofibers. The hybrid effect of nitrogen doping, porous structure, and abundant active sites effectively inhibits the structural damage of MnO 2. The as-prepared δ-MnO 2 -CNFs cathode achieves a high specific capacity of 232.9 mAh g−1 and energy density of 450.7 Wh kg−1 at a current density of 100 mA g−1, and could be stably cycled for 500 cycles at a high current rate of 1 A g−1. The density functional theory calculation results show that the synergistic effect in δ-MnO 2 -CNFs is more conducive to the transfer of zinc ions. Furthermore, a salty ice electrolyte Zn(ClO 4) 2 has been used for the Zn//δ-MnO 2 -CNFs cell, which can work at a low temperature of −20 °C, and a stable low temperature (0 °C) cycle of 500 cycles is achieved at 1 A g−1. [ABSTRACT FROM AUTHOR]

Malate transporter proteins (MTPs) play a pivotal role in regulating flux in the citrate/malate/pyruvate shuttle to deliver acetyl-CoA from the mitochondria to the cytosol and thus regulate lipid biosynthesis in oleaginous fungi. Despite the recent successful exploration of the mitochondrial malate transporters in Mucor circinelloides, research with in silico analyses that include molecular docking and their dynamics, in addition to homology modelling of malate transporters, have not been reported. In this study, the physico-chemical properties and nucleotide sequence analysis of two mitochondrial MTPs (MT and SoDIT-a with Gene/protein ID scafold00018.48 and scafold00239.15, respectively), in M. circinelloides WJ11 were performed. The three-dimensional (3D) model of the mitochondrial MTPs was determined and the best-docked complex stabilities were demonstrated with molecular dynamic (MD) simulations. The activity domain was revealed to form hydrogen bonds and piling interactions with citrate and malate upon docking. Our study showed better binding affinities for the MTPs—reaching up to −3.44 and −7.27 kcal/mol with the MT and SoDIT-a proteins, respectively (compared to the target of −2.85 and −6.00 kcal/mol for citric acid-binding). MD simulations illustrated that the protein complexes demonstrated conformational stability throughout the simulation. This study was the first to elucidate the structural characteristics of mitochondrial MTPs in M. circinelloides WJ11, providing direct evidence regarding the transport mechanism of specific substrates. Furthermore, the current results support ongoing efforts to combine functional and structural data to better understand the MTPs (at the molecular and atomic levels) of an oleaginous fungus such as M. circinelloides. [ABSTRACT FROM AUTHOR]

Linolenic acid (LA) is gaining more interest within the scientific community. This is because it has a potential medical role in reducing the risk of inflammation, carcinogenesis, atherosclerosis and diabetes and is a valuable nutraceutical for human health. The oleaginous fungus Mucor circinelloides produces a high lipid content (36%), including valuable polyunsaturated fatty acids (PUFAs). However, the critical step in which oleic acid (OA) is converted into LA is not efficient at supplying enough substrates for PUFA synthesis. Hence, we propose a method to increase LA production based on genetic engineering. The overexpression of the Δ12-desaturase gene from M. circinelloides and Mortierella alpina increased the LA content and improved the lipid accumulation (from 14.9% to 21.6% in the Δ12-desaturase gene of the M. circinelloides overexpressing strain (Mc-D12MC) and from 14.9% to 18.7% in the Δ12-desaturase gene of M. alpina overexpressing strain (Mc-D12MA)). Additionally, the up-regulated expression levels of these genes targeted the genes involved in NADPH production, implying that the elevated Δ12-desaturase gene may function as a critical regulator of NADPH and lipid synthesis in M. circinelloides. This study provides the first evidence to support the design of metabolic engineering related to LA and PUFA production in M. circinelloides for potential industrial applications. [ABSTRACT FROM AUTHOR]

Silicon anodes are important candidates for high energy lithium-ion batteries (LIBs) because of their large theoretical specific capacity. However, silicon usually undergoes severe volume changes (300–400 %) in the lithiation/delithiation process, resulting in low Coulombic efficiency (CE) and rapid capacity decay. Herein, the nanotube shaped silicon-carbon composite has been designed by using a simple dealloying method in greenhouse gas (CO 2) environment. Encouragingly, the tubular structured composite prepared at 1.5 h shows best electrochemical performance as anodes for LIBs among the three samples. The first specific discharge capacity could reach 2302.5 mA h g−1 when cycled at 0.2 A g−1, corresponding an initial CE of 70 %. Along with the increasing number of cycles, the composite exhibits high Coulombic efficiency compared to commercial Si particles. The material also displays excellent rate capacity and stability with a high specific capacity of 714.6 mA h g−1 at 5 A g−1. In situ differential electrochemical mass spectrometry is further used to analyze the phenomenon of gas generation during the formation of solid electrolyte interface layer. In addition, the fabricated Si/LiNi 0.3 Co 0.3 Mn 03 O 2 full battery demonstrates high initial specific capacity up to 171 mA h g−1 as well as moderate cycling stability for 50 cycles. The silicon nanoparticles confined in carbon nanotubes has been engineered by a simple dealloying strategy in carbon dioxide gas environment. The as-obtained composite exhibits excellent performance with high specific capacity and excellent cycling stability in both half and full cells. Furthermore, in situ differential electrochemical mass spectrometry technique is used to analyze gas evolution during the formation of solid electrolyte interface layer. This work has important scientific significance for CO 2 recycling and the development of large-scale energy storage technology. [Display omitted] • Si confined in carbon nanotubes is engineered in greenhouse gas environment. • The introduction of CO 2 contributes to carbon coating and silicon production. • The composite exhibits high reversibility and outstanding cycling stability. • Greenhouse gas has achieved efficient carbon conversion for energy storage. • The preparation is simple and expected to realize large-scale preparation. [ABSTRACT FROM AUTHOR]

Lipid biosynthesis is a significant metabolic response to nitrogen starvation in oleaginous fungi. The oleaginous fungus Mucor circinelloides copes with nitrogen stress by degrading AMP through AMP deaminase (AMPD). However, the mechanism of AMPD in regulating lipogenesis remains largely unclear. To elucidate the mechanism of AMPD in lipid synthesis in this M. circinelloides , we identified two genes (ampd1 and ampd2) encoding AMPD and constructed an ampd double knockout mutant. The engineered M. circinelloides strain elevated cell growth and lipid accumulation, as well as the content of oleic acid (OA) and gamma-linolenic acid (GLA). In addition to the expected increase in transcription levels of genes associated with lipid and TAG synthesis, we observed suppression of lipid degradation and reduced amino acid biosynthesis. This suggested that the deletion of AMPD genes induces the redirection of carbon towards lipid synthesis pathways. Moreover, the pathways related to nitrogen metabolism, including nitrogen assimilation and purine metabolism (especially energy level), were also affected in order to maintain homeostasis. Further analysis discovered that the transcription factors (TFs) related to lipid accumulation were also regulated. This study provides new insights into lipid biosynthesis in M. circinelloides , indicating that the trigger for lipid accumulation is not entirely AMPD-dependent and suggest that there may be additional mechanisms involved in the initiation of lipogenesis. [Display omitted] • Deletion of ampd genes increases lipogenesis in Mucor circinelloides. • AMPD plays an essential role in the regulation of lipid and nitrogen metabolism. • Deletion of ampd genes regulates energy metabolism to maintain homeostasis. • TFs involved in lipogenesis are regulated after knockout of ampd genes. [ABSTRACT FROM AUTHOR]

Despite the progress made on the production of graphene using liquid‐phase exfoliation methods, the fabrication of graphene with both high conductivity and dispersibility remains challenging. Through catalytic exfoliation of graphite, an effective synthesis method for graphene with large lateral size (≈10 µm), high conductivity (926 S cm–1), and excellent water solubility (≈10 mg mL–1) is reported herein. Such graphene can be used broadly for applications such as lithium ion batteries, where both high conductivity and dispersibility are required. As an example, the synthesis of graphene and lithium‐iron‐phosphate composites is demonstrated, which leads to electrodes with dramatically improved cycling stability and rate performance. Adaption of such material leads to electrodes with volumetric energy density as high as 658.7 and 287.6 W h L–1 under 0.5 and 20 C, respectively, which is significantly higher than that of commercial LiFePO4 (394.7 and 13.5 W h L–1 at 0.5 and 20 C, respectively). This work provides a new method of making high‐conductivity–dispersibility graphene for various applications. [ABSTRACT FROM AUTHOR]

Lithium-ion battery (LIBs) applications using antimony (Sb) based anodes with high specific capacity and suitable operating voltage have showed tremendous potential. However, the large volume variation during electrochemical cycling limits their application. In this paper, M-Sb (M=Co, Ni) nanoparticles embedded in nitrogen doped carbon nanofibers have been prepared by an electrospinning method, 3D interconnected M-Sb@CN (NiSb@CN and Sb/CoSb 2 @CN) fiber composites are obtained finally. M-Sb nanoparticles are uniformly distributed in N-doped carbon nanofibers, which can prevent their direct exposure to the electrolyte. Compared with bare Sb-M and Sb-C binary electrodes, the M-Sb-C three-component composite electrodes show smaller volume change and stronger charge transport ability. The introduction of the transition metal (Co, Ni) not only serves as buffer substrate for volume change, but also regulates the properties of carbon fibers as a catalyst. High reversible capacities of 647.4 and 620.2 mA h g−1 of NiSb@CN and Sb/CoSb 2 @CN fiber composites can be maintained after 600 cycles at a current rate of 500 mA g−1. First principles calculation demonstrates that N-doping and the incorporation of transition metal M have favorable effect on the improved Li binding energy, offering a possibility for the material design of the high-performance LIBs. [ABSTRACT FROM AUTHOR]