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旨在为进一步构建脂肪酸高产菌株奠定基础，通过异源和同源表达，研究了谷氨酸棒状杆菌ATCC13032中硫酯酶的基因（NCgl2365 和 NCgl0090）对脂肪酸合成的影响。结果表明：硫酯酶的过表达对大肠杆菌和谷氨酸棒状杆菌中脂肪酸的种类和含量都产生了影响；基因 NCgl2365 在大肠杆菌中过表达后脂肪酸产量增加了37.86%，且促进了饱和脂肪酸C16∶ 0、C18∶ 0和不饱和脂肪酸C17∶ 1和C20∶ 3的生成，在谷氨酸棒状杆菌中同源表达后脂肪酸产量提高了33.43%，C17∶ 0相对含量增加了51.82%，而C6∶ 0、C8∶ 0、C12∶ 0、C17∶ 1、C18∶ 0、C18∶ 1和C18∶ 3的相对含量显著减少；基因 NCgl0090 在大肠杆菌中过表达后脂肪酸产量增加了58.15%，促进了饱和脂肪酸C14∶ 0、C16∶ 0、C18∶ 0和不饱和脂肪酸C17∶ 1的生成，而在谷氨酸棒状杆菌中同源表达后脂肪酸产量提高了59.12%，其中C16∶ 0相对含量增加了40.18%，促进了C10∶ 0、C14∶ 0、C14∶ 1、C15∶ 0、C16∶ 1、C18∶ 2、C20∶ 1和C21∶ 0 8种新脂肪酸的合成。综上，基因 NCgl2365 和 NCgl0090 对宿主菌体中的脂肪酸代谢产生了重要的作用。In order to lay the foundation for further construction of fatty acid high-yield strains, the effects of the genes for thioesterases (NCgl2365 and NCgl0090) in Corynebacterium glutamicum ATCC13032 on fatty acid synthesis were determined by heterologous and homologous expression. The results showed that overexpression of thioesterases affected both the type and content of fatty acids in Escherichia coli and Corynebacterium glutamicum. Gene NCgl2365 increased fatty acid production by 3786% after overexpression in Escherichia coli and promoted the production of saturated fatty acids C16∶ 0, C18∶ 0, and unsaturated fatty acid C17∶ 1 and C20∶ 3; fatty acid production increased by 3343% after homologous expression in Corynebacterium glutamicum, and the relative content of C17∶ 0 increased by 51.82%, whereas the relative contents of C6∶ 0, C8∶ 0, C12∶ 0, C17∶ 1, C18∶ 0, C18∶ 1 and C18∶ 3 decreased. Fatty acid production increased by 58.15% after overexpression of gene NCgl0090 in Escherichia coli, which contributed to the production of saturated fatty acids C14∶ 0,C16∶ 0, C18∶ 0, and unsaturated fatty acid C17∶ 1; fatty acid production increased by 59.12% after homologous expression in Corynebacterium glutamicum, with 40.18% increase in the relative content of C16 ∶ 0, the synthesis of eight new fatty acids, C10∶ 0,C14∶ 0, C14∶ 1, C15∶ 0, C16∶ 1, C18∶ 2, C20∶ 1 and C21∶ 0 was promoted. In conclusion, the genes NCgl2365 and NCgl0090 exerted important effects on fatty acid metabolism in the host bacteriophage.

In this study, we investigated the bacterial community composition and structure during the fermentation process of traditional light-flavor baijiu using PacBio SMRT sequencing technology, and further explored the mechanism of bacterial community self-assembly during the fermentation process using a framework to quantitatively infer community assembly mechanisms by phylogenetic bin-based null model analysis (iCAMP). The results showed that the bacterial diversity decreased and then increased during the fermentation process. Lactobacillus, Acetobacter, Pediococcus and Weissella were identified as the dominant genera, and L. pontis, L. paralimentarius, L. brevis and L. acetotolerans as the dominant species. According to the differences among bacterial communities at different fermentation times, the whole fermentation process could be divided into three stages: I (0 days), II (3–10 days) and III (12–28 days). Acetobacter malorum, L. paralimentarius and L. pontis were the differential species in stages I, II and III, respectively, and there were a significant negative correlation between the differential species in different stages and a significant positive correlation between the differential species in the same fermentation stage. In addition, turnover was the major process responsible for bacterial community changes, and drift during stoichiometry was the most important process driving bacterial community self-assembly. Meanwhile, starch content, temperature and moisture content may be the main factors influencing bacterial community self-assembly during fermentation. The above results provide insight into the bacterial species composition, community succession patterns and self-assembly mechanisms during the fermentation of traditional light-flavor baijiu, which can provide a theoretical basis for regulating the microbial communities in the baijiu brewing process and further optimizing the role of multiple microorganisms in the mixed fermentation process.

旨在为脂肪酸高产菌株的筛选和构建奠定理论基础，研究谷氨酸棒杆菌脂肪酸合成酶A（FasA）对大肠杆菌脂肪酸合成的影响，利用生物信息学软件预测分析了FasA的性质并构建过表达载体pXMJ19-fasA，转化至大肠杆菌进行表达,对表达诱导剂异丙基-β-D-硫代吡喃半乳糖苷（IPTG）浓度进行考察，并测定了异源表达后的脂肪酸组成。结果表明，重组菌株在IPTG浓度为1 mmol/L下诱导20 h，棕榈油酸和油酸产量分别达到1.735、2.325 mg/g，与对照菌株相比分别提高了53.95%和59.68%。研究结果说明FasA对大肠杆菌合成棕榈油酸和油酸有促进作用。 In order to lay a theoretical foundation for screening and constructing fatty acid high-yielding strains, the effects of Corynebacterium glutamicum fatty acid synthase A (FasA) on the synthesis of fatty acids in E. coli were studied, the properties of FasA were predicted and analyzed using bioinformatics software, moreover the overexpression vector pXMJ19-fasA was constructed and transformed into E. coli for expression, the concentration of expression inducer isopropyl-β-D-thiogalactoside (IPTG) was investigated and the fatty acid composition after heterologous expression was determined.The results showed that when the recombinant strain was induced under the IPTG concentration of 1 mmol/L for 20 h，the yield of palmitoleic acid and oleic acid reached 1.735，2.325 mg/g ，which increased by 53.95% and 59.68% respectively compared with the control strain. These results indicate that FasA can promote the synthesis of palmitoleic acid and oleic acid by E. coli.

Regulating the binding effect between the surface of an electrode material and reaction intermediates is essential in highly efficient CO2 electro‐reduction to produce high‐value multicarbon (C2+) compounds. Theoretical study reveals that lattice tensile strain in single‐component Cu catalysts can reduce the dipole–dipole repulsion between *CO intermediates and promotes *OH adsorption, and the high *CO and *OH coverage decreases the energy barrier for C−C coupling. In this work, Cu catalysts with varying lattice tensile strain were fabricated by electro‐reducing CuO precursors with different crystallinity, without adding any extra components. The as‐prepared single‐component Cu catalysts were used for CO2 electro‐reduction, and it is discovered that the lattice tensile strain in Cu could enhance the Faradaic efficiency (FE) of C2+ products effectively. Especially, the as‐prepared CuTPA catalyst with high lattice tensile strain achieves a FEC2+ of 90.9 % at −1.25 V vs. RHE with a partial current density of 486.1 mA cm−2. [ABSTRACT FROM AUTHOR]

乙酰辅酶A羧化酶是谷氨酸棒杆菌中调控脂肪酸合成的关键酶。为了研究乙酰辅酶A羧化酶α亚基（accBC）基因对脂肪酸合成的影响，以accBC表达的菌株重组谷氨酸棒杆菌G-BC为材料，研究了诱导剂异丙基-β-D-硫代半乳糖苷（IPTG）浓度、培养时间、培养温度对重组谷氨酸棒杆菌G-BC脂肪酸产量的影响，并通过响应面法优化了重组谷氨酸棒杆菌G-BC产脂肪酸的培养条件，同时与原始菌株脂肪酸产量进行了对比。结果表明：重组谷氨酸棒杆菌G-BC产脂肪酸的最佳条件为诱导剂浓度1 mmol/L 、培养时间20 h、培养温度32 ℃，在此条件下脂肪酸产量为34.56 mg/g（以菌体干质量计），比原始菌株提高了1.68倍。说明乙酰辅酶A羧化酶α亚基对于谷氨酸棒杆菌合成脂肪酸有促进作用。 Acetyl-CoA carboxylase is a key enzyme regulating fatty acid synthesis in Corynebacterium glutamicum. In order to study the effect of acetyl-CoA carboxylase α subunit (accBC) gene on fatty acid synthesis,the recombinant Corynebacterium glutamicum G-BC(expression strain of accBC) was used as raw material, the effects of inducer(isopropyl-β-D-thiogalactopyranoside,IPTG) concentration, culture time and culture temperature on the yield of fatty acid were studied. Moreover, the culture conditions for fatty acid production of recombinant Corynebacterium glutamicum G-BC were optimized by response surface methodology. The fatty acid yield of the original strain and the recombinant strain was also compared.The results showed that the optimal culture conditions were obtained as follows: inducer concentration 1 mmol/L, culture time 20 h, and culture temperature 32 ℃. Under these conditions, the yield of fatty acid was 34.56 mg/g（based on dry weight of bacteria）, which was 1.68 times higher than original strain. The accBC can promote the synthesis of fatty acid by Corynebacterium glutamicum.

Layered double hydroxide (LDH) nanostructures are commonly used to study the interfacial effects of Pt‐based catalysts in CO oxidation. However, the specific role and detailed intermediates involved in CO oxidation remain unclear. Density functional theory (DFT) predicted that NiFe LDH loaded with single Pt atoms would exhibit satisfactory CO oxidation activity. On this basis, we prepared Pt1NiFe LDH catalysts with various Fe : Ni ratios by using the one‐pot method and achieved favorable dispersion of single Pt atoms. Pt1/FN‐1, which had the optimal Fe : Ni ratio (1 : 1), exhibited satisfactory catalytic performance for CO oxidation and a high turnover frequency, as determined through DFT calculations and experimental characterization. In‐situ diffuse reflectance infrared Fourier transform spectroscopy confirmed that CO directly reacted with Pt1/FN‐1 to produce CO2 and that introduced O2 formed bicarbonate species to produce CO2 together with the adsorbed CO on Pt1 sites. Overall, our work provides new insights into the catalytic mechanism of the well‐known Pt1NiFe LDH catalysts in CO oxidation. [ABSTRACT FROM AUTHOR]