Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Identification of residues important for the activity of aldehyde-deformylating oxygenase through investigation into the structure-activity relationship
No full textBackground: Aldehyde-deformylating oxygenase (ADO) is a key enzyme involved in the biosynthetic pathway of fatty alk(a/e)nes in cyanobacteria. However, cADO (cyanobacterial ADO) showed extreme low activity with the k(cat) value below 1 min(-1), which would limit its application in biofuel production. To identify the activity related key residues of cADO is urgently required
我国单晶市场热潮正在兴起
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光伏发电技术新突破，实现降本增效：（1）单晶硅片完成了从砂浆线到金刚线切的转变，使其切割效率提升了50%以上；（2）以连续拉晶工艺，提高了单晶硅棒生产率，产量提升，成本降低。单晶比多晶可节约土地租金5%、运维成本6%，且每瓦发电量至少比多晶高3%。</p>
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分布式光伏发电助力单晶硅发展：国家能源局“领跑者”计划设定单多晶硅效率下限标准，多晶产品约有20%符合，而单晶产品几乎100%符合。基于屋顶的分布式发电使单晶可以在有限的屋顶获得更多功率的装机量。《电力发展“十三五”规划》提出“十三五”期间分布式光伏装机达6000万千瓦以上。</p>
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预计，高效电池将主导市场，单晶硅电池市场份额到2025年达到48%，其中N型单晶硅电池的市场份额由2016年的3.5%提高到2025年的30%。</p>
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全文见附件。</p>
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监测：规划战略 图书馆</p>
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信息来源：杨鲲鹏.我国单晶市场热潮正在兴起[N/OL].<a href="http://www.escn.com.cn/news/show-452520.html">http://www.escn.com.cn/news/show-452520.html</a></p
In vitro oxidative decarboxylation of free fatty acids to terminal alkenes by two new P450 peroxygenases
No full textBackground: P450 fatty acid decarboxylases represented by the unusual CYP152 peroxygenase family member OleT(JE) have been receiving great attention recently since these P450 enzymes are able to catalyze the simple and direct production of 1-alkenes for potential applications in biofuels and biomaterials. To gain more mechanistic insights, broader substrate spectra, and improved decarboxylative activities, it is demanded to discover and investigate more P450 fatty acid decarboxylases
Expansion of chemical space for natural products by uncommon P450 reactions
No full textC Cytochrome P450 enzymes (P450s) are the most versatile biocatalysts in nature. The catalytic competence of these extraordinary hemoproteins is broadly harnessed by numerous chemical defenders such as bacteria, fungi, and plants for the generation of diverse and complex natural products. Rather than the common tailoring reactions (e.g. hydroxylation and epoxidation) mediated by the majority of biosynthetic P450s, in this review, we will focus on the unusual P450 enzymes in relation to new chemistry, skeleton construction, and structure re-shaping via their own unique catalytic power or the intriguing protein-protein interactions between P450s and other proteins. These uncommon P450 reactions lead to a higher level of chemical space expansion for natural products, through which a broader spectrum of bioactivities can be gained by the host organisms
Structural insights into the substrate specificity of a glycoside hydrolase family 5 lichenase from Caldicellulosiruptor sp F32
No full textGlycoside hydrolase (GH) family 5 is one of the largest GH families with various GH activities including lichenase, but the structural basis of the GH5 lichenase activity is still unknown. A novel thermostable lichenase F32EG5 belonging to GH5 was identified from an extremely thermophilic bacterium Caldicellulosiruptor sp. F32. F32EG5 is a bi-functional cellulose and a lichenan-degrading enzyme, and exhibited a high activity on beta-1,3-1,4-glucan but side activity on cellulose. Thin-layer chromatography and NMR analyses indicated that F32EG5 cleaved the beta-1,4 linkage or the beta-1,3 linkage while a 4-O-substitued glucose residue linked to a glucose residue through a beta-1,3 linkage, which is completely different from extensively studied GH16 lichenase that catalyses strict endo-hydrolysis of the beta-1,4-glycosidic linkage adjacent to a 3-O-substitued glucose residue in the mixed-linked beta-glucans. The crystal structure of F32EG5 was determined to 2.8 angstrom resolution, and the crystal structure of the complex of F32EG5 E193Q mutant and cellotetraose was determined to 1.7 angstrom resolution, which revealed that the exit subsites of substrate-binding sites contribute to both thermostability and substrate specificity of F32EG5. The sugar chain showed a sharp bend in the complex structure, suggesting that a substrate cleft fitting to the bent sugar chains in lichenan is a common feature of GH5 lichenases. The mechanism of thermostability and substrate selectivity of F32EG5 was further demonstrated by molecular dynamics simulation and site-directed mutagenesis. These results provide biochemical and structural insights into thermostability and substrate selectivity of GH5 lichenases, which have potential in industrial processes
Nitrogen-Doped Porous Graphdiyne: A Highly Efficient Metal-Free Electrocatalyst for Oxygen Reduction Reaction
No full textMetal-free catalysts for oxygen reduction reaction (ORR) are the desired materials for low-cost proton exchange membrane fuel cells. Graphdiyne (GDY), a novel type of two-dimensional carbon allotrope, is featured by its sp- and sp(2)-hybridized carbon atoms, different from the other existing carbon materials. Thus, nitrogen (N) can be doped in new styles by substituting sp-hybridized carbon atoms, effective for ORR, which has been displayed in this study using both experimental and theoretical technologies. The N-doped GDY was synthesized with pyridine and NH3 as N sources successively, expressing an electrocatalytic activity at a potential above 0.8 V similar to that of commercial Pt/C for ORR in alkaline solution and higher stability and better methanol tolerance than those of Pt/C
Graphdiyne Nanowalls as Anode for Lithium-Ion Batteries and Capacitors Exhibit Superior Cyclic Stability
No full textIn this study, we reported the design and application of hierarchical porous Graphdiyne Nanowall (GDY - NW) for energy storage device as lithium - ion batteries (LIBs) and capacitors (LICs). The unique hierarchical porous with the presence of butadiyne linkages comprising sp - and sp(2-) hybridized carbon atoms reinforces not only providing rich active sites for lithium storage, but also the efficient pathways for fast ion diffusion. Future more, the stable SEI layer formed on the GDY - NW surface after the initial cycle which can effectively reduce the resistance of interface and thus stable the circulating batteries, confirmed directly through the in - situ Raman measurement. The GDY - NW electrodes exhibit a reversible capacity of approximately 908 mAh g(-1) at 0.05A g(-1), excellent cyclic stability with retention of 526 mAh g(-1) at large rate of 1 A g(-1) after 1000 cycles applied as anode for LIBs. Thus GDY - NW films could deliver a capacitance more than 189 F g(-1) over 10000 cycles at 1 A g(-1) for LICs with active carbon cathode and exhibit an initial specific energy as high as 217 Wh kg(-1) at a power density of 100W kg(-1), presenting the benefit of the unique hierarchical porous structure comprising amount of macro, meso - and micro - pores, for thus high performance capability and cyclicity for renewable energy lithium storage. (C) 2017 Elsevier Ltd. All rights reserved
Nonadiabatic dynamics simulation of keto isocytosine: a comparison of dynamical performance of different electronic-structure methods
No full textThe nonadiabatic dynamics of keto isocytosine in the gas phase has been investigated using the on-the-fly trajectory surface hopping method based on two electronic-structure methods: SA-CASSCF and ADC(2). The resuLts estimate an excited-state Lifetime of around 1000 fs at the SA-CASSCF level, while a much shorter Lifetime of 250-350 fs is obtained at the ADC(2) level. Although three conical intersections (Cis) (Ethyl. 1, Ethyl. 11 and C=0 stretching) are relevant to the nonadiabatic decay of keto isocytosine, their contributions to the nonadiabatic decay are highly dependent on the electronic structure methods employed in the dynamics simulation. The Ethyl. 11 CI is the main channel in the dynamics simulations at the SA-CASSCF level, while the C=0 stretching CI becomes dominant at the ADC(2) Levels. Other high-level electronic-structure methods (MR-CISD and MS-CASPT2) are involved to benchmark our dynamics resuLts. Through the analysis of the reaction pathways from the ground state minimum to the relevant Cls, we expect that the excited-state dynamical features obtained at the MR-CISD and MS-CASPT2 levels should be very similar to those at the SA-CASSCF level. The comparison of resuLts obtained using different excited-state electronic-structure methods could provide guidance for further studies of similar systems
Rescuing ethanol photosynthetic production of cyanobacteria in non-sterilized outdoor cultivations with a bicarbonate-based pH-rising strategy
No full textBackground: Ethanol photosynthetic production based on cyanobacteria cell factories utilizing CO2 and solar energy provides an attractive solution for sustainable production of green fuels. However, the scaling up processes of cyanobacteria cell factories were usually threatened or even devastated by biocontaminations, which restricted biomass or products accumulations of cyanobacteria cells. Thus it is of great significance to develop reliable bio-contamination- controlling strategies for promoting ethanol photosynthetic production in large scales