Sclareol, a precursor for synthesis of fragrant chemical compound Ambrox, is traditionally extracted from the flowers and leaves of Salvia sclarea. However, it requires laborious and cost-intensive purification procedures due to the low concentration of sclareol in complex mixtures.
　　Recently, a research group led by Prof. ZHOU Yongjin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has established a synthetic biology approach for diterpenoid production. They systematically engineered the brewing yeast Saccharomyces cerevisiae to produce sclareol.
　　This study was published in Metabolic Engineering on Nov. 9.
　　Engineering yeast for high-level production of diterpenoid sclareol (Image by CAO Xuan)
　　The researchers systematically engineered brewing yeast Saccharomyces cerevisiae for overproduction of sclareol by engineering the isoprenoid biosynthetic pathways. This revired its central metabolism and enhanced supply of precursor and cofactor.
　　For convenient manipulation, they developed a metabolic transforming strategy to transform a fatty-overproducing strain Y&Z036 toward sclareol overproduction at a modular manner, which facilitated the construction of versatile cell factories.
　　"Transcriptome and metabolic flux analysis showed that the global metabolic rewiring improved diterpenoid biosynthesis. Our strategy may improve the production of other acetyl-CoA-derived molecules," said Prof. ZHOU.
　　This work was supported by the National Natural Science Foundation of China, and the Key project at central government level. (Text by CAO Xuan)

　　Neuron cells are directly associated with neurodegenerative diseases. However, they are not isolated. They interact/communicate with other surrounding cells through physical contact, signal-ligand pathway, and other means to realize neural functions cooperatively.
　　Recent studies have shown that the nervous system and the immune system have close interaction/communication with each other, and the immune cells in the brain play a key role in shaping and regulating the neural function of neuron cells.
　　Now, a research team led by Prof. LU Yao from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) decoded the secretome-mediated neuron-immune cell interaction network with single-cell integrative secretion profiling technology.
　　This study was published in Proceedings of the National Academy of Sciences on Oct. 26.
　　Mapping secretome-mediated interaction between paired neuron–macrophage single cells (Image by DENG Jiu)
　　Although previous studies have analyzed the interaction between neuron-immune cells at the population cell level, the actual interaction/communication through multiple secretory factor signals in both physiological and pathological conditions are still unclear.
　　In this work, the researchers realized the mapping of 12 different secreted factors from high throughput single-neuron cells, including cytokines, neurotrophic factors, and neuron-derived exosomes, with single-cell integrative secretion profiling technology. They revealed the heterogeneity and correlation of different secreted factors in neuron cells.
　　Moreover, they applied the technology to paired neuro-immune single-cell interaction studies and found that infiltrating macrophages and resident macrophages (microglia) played different roles in neuronal secretion regulation. For example, infiltrating macrophages tended to inhibit neuronal secretion of neuron-derived exosomes, and microglia would promote neurosecretion in exosomes.
　　"We also found that the interaction of neuron cells with macrophages or microglia in the Alzheimer's disease model leads to increased secretion of pro-inflammatory cytokines," said Prof. LU.
　　This study provides a new technology for the in-depth understanding of the brain microenvironment, which helps discover markers for the occurrence and development of neurodegenerative diseases.
　　The work was supported by the National Natural Science Foundation of China and the Youth Promotion Association of CAS. (Text by DENG Jiu)

　　A research group led by Assoc. Prof. LUO Nengchao and Prof. WANG Feng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences realized selective control of photocatalytic coupling reaction of alcohols.
　　This study was published in Journal of the American Chemical Society on Oct. 10.
　　Radicals are common intermediates in photocatalytic conversions, with open-shell electronic structures. They are highly active and readily adsorb on the surface of semiconductors strongly, resulting in a variety of reactions. Solution can influence the product selectivity and quantum yield of the photocatalytic reaction.
　　Steering the reaction paths of αHRs toward C-C bond coupling by forming hydrogen bonds (Image by MU Junju and GAO Zhuyan)
　　In this work, the researchers found that adding 5 vol% water to ethanol solution could increase the selectivity of 2,3-butanediol generated by photocatalytic coupling of ethanol from 37% to 57%, with a reaction rate 2.4 times of the original.
　　Using radical trapping experiments, deuterium experiments, DFT calculations, and molecular dynamics simulations, they found that the introduction of a small amount of water enabled the intermediate α-hydroxyethyl radical (αHR) to form hydrogen bonds with solvent molecules both on the catalyst surface and in bulk solution. With the help of hydrogen bonding, αHR tended to desorb from the catalyst surface and was stabilized in solution, avoiding the predominant oxidation of αHR to acetaldehyde and reverse reaction between αHRs and H· that recoverd ethanol.
　　"Our study revealed that non-chemical bonding interactions can steer the reaction paths of radicals for selective photocatalysis," said LUO.
　　This work was supported by the Ministry of Science and Technology of the People's Republic of China, the National Natural Science Foundation of China, the Liaoning Revitalization Talents Program, the Fundamental Research Funds for the Central Universities, the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy, and by Dalian Institute of Chemical Physics, CAS. (Text by GAO Zhuyan)

　　A research team led by Prof. WU Zhong-Shuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has developed all-3D printed Li metal batteries (LMBs) with robust cycle stability and ultrahigh areal energy density.
　　The LMBs take a porous and conductive Ti3C2Tx MXene skeleton for dendrite-free and stable Li metal anode and multi-dimensionally conductive LiFePO4 (LFP) lattice as ultra-thick cathode.
　　This study was published in Energy Storage Materials on Oct. 19.
　　LMBs are considered as a class of high-energy-density systems beyond current state-of-the-art lithium-ion batteries. Nevertheless, the uncontrollable dendrite growth and huge volume change of Li metal anodes have raised poor cycle life.
　　Schematic illustration of the fabrication process of 3D printed LMBs (Image by MA Jiaxin and ZHENG Shuanghao)
　　In this study, the researchers reported an all-3D printing approach for constructing ultrahigh-performance LMBs. The LMBs were comprised of a dendrite-free Li metal anode with porous MXene lattices to regulate local current distribution, which homogenized the lithium nucleation, and a 3D conductive porous LFP framework cathode to achieve fast ion/electron transfer channels.
　　Due to the abundance of Li nucleation sites and large pore volume in the MXene lattices, the 3D printed MXene scaffolds prevented the infinite volume change and dendritic formation of Li anodes.
　　Furthermore, by pairing ultra-thick LFP cathodes lattices with high-efficiency electron and ion networks, the all-3D printed LFP||MXene@Li LMBs delivered unprecedented areal capacity (25.3 mAh/cm2) and energy density (81.6 mWh/cm2) under an ultrahigh mass loading of 171 mg/cm2, exceeding all reported 3D printed batteries so far.
　　This work was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of CAS, and Dalian National Laboratory for Clean Energy of CAS. (Text by MA Jiaxin and ZHENG Shuanghao)

　　A research group led by Prof. GUO Jianping and Prof. CHEN Ping from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. WU An'an from Xiamen University, revealed how lithium hydride mediated hydrogenolysis of anilines to arenes.
　　This study was published in Journal of the American Chemical Society on Sep. 15.
　　Lithium hydride mediated transition metal-free hydrogenolysis of anilines to arenes (Image by CAI Yongli)
　　C-N bonds are ubiquitous in organic and biomacromolecules. The activation of C-N bonds is involved in many important chemical processes. Because of the high C-N bond dissociation energy, the intense coordinating ability, and the inferior leaving ability of the NH2 group, the cleavage of C-N bond, specially the sp2C-N bond remains challenging.
　　The researchers proposed a lithium hydride (LiH)-mediated chemical looping process for the hydrogenolysis of aniline, which decoupled the overall hydrodenitrogenation (HDN) reaction into a set of separated steps.
　　In the first step of the loop, LiH deprotonated aniline to form a lithium anilide and H2. The lithium anilide was then exposed to dihydrogen at elevated temperatures to produce benzene and lithium amide (LiNH2) in the second step. And in the last step, the LiH was regenerated by the hydrogenation of LiNH2 in a flow of H2, closing the chemical cycle.
　　They found that benzene was the dominant denitrogenated product in this process, which was in sharp contrast to those of transition metals. This led to the complete hydrogenation of aromatic rings. Therefore, they achieved a highly denitrogenated product formation rate under lower temperatures and pressures, which was comparable to the catalytic rate of transition metal catalysts.
　　The computational studies revealed that the cleavage of C-N bond was facilitated via a LiH-mediated pathway, in which the hydride (H-) of LiH functioned as a nucleophile to attack the α-sp2C atom and Li cation interacted with the distorted aromatic ring by a cation-π interaction.
　　"This work provides a new strategy for C-N bond activation and may help the design and development of new materials or catalysts for the HDN as well as other important chemical transformations," said Prof. GUO. (Text by CAI Yongli)

　　A joint research team led by Prof. PAN Xiulian, Prof. BAO Xinhe and Prof. HOU Guangjin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed the reaction mechanism of ketene transformation to gasoline on the zeotype H-SAPO-11.
　　The study was published in Journal of the American Chemical Society on Oct. 3.
　　In 2016, the team proposed a new catalyst concept based on metal oxide-zeolite bifunctional catalysts and ketene intermediate was detected by highly sensitive synchrotron-based vacuum ultraviolet photoionization mass spectrometry during syngas conversion.
　　Further studies demonstrated that ketene can be converted to mixed light olefins over SAPO-34 and transformed to ethene over the eight-membered ring side pocket acid sites of mordenite. Although ketene has also been identified as an important intermediate in other zeolite-catalyzed C1 chemistry, its transformation mechanism is not well understood.
　　Chemistry of ketene transformation to gasoline catalyzed by H SAPO-11(Image by ZHANG Yang and GAO Pan)
　　In this study, the researchers studied ketene conversion over H-SAPO-11 employing kinetic analyses, in situ infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy.
　　They found that ketene transformed to butene on the acid sites via either acetyl species following an acetic acid ketonization pathway or acetoacetyl species with keto-enol tautomerism following an acetoacetic acid decarboxylation pathway in the presence of water.
　　"Our study revealed experimentally for the first time on the reaction network of catalytic ketene conversion over zeotypes and may benefit the further understanding of C1 chemistry," said Prof. PAN. 
　　This work was supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China, the Liaoning Revitalization Talents Program, the China National Postdoctoral International Exchange Program, the China National Postdoctoral Program for Innovative Talents, and the China Postdoctoral Science Foundation. (Text by ZHANG Yang and GAO Pan)