Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Optimization of genome shuffling for high-yield production of the antitumor deacetylmycoepoxydiene in an endophytic fungus of mangrove plants
No full textAs an accelerated evolutionary tool, genome shuffling is largely dependent on the high fusion frequency of different parental protoplasts. However, it was unclear how many types of parental protoplasts would afford the highest fusion frequency. Here, we applied the Monte Carlo method to simulate the simplified processes of protoplast fusion, to achieve maximal useful fusions in genome shuffling. The basic principle of this simulation is that valid fusions would take place when the minimum distance between two different types of parent protoplasts is smaller than that between two of the same types. Accordingly, simulations indicated that the highest fusion frequency would be achieved from eight to 12 different parental protoplasts. Based on the simulation results, eight parental protoplasts of the fungal endophyte Phomopsis sp. A123 were subjected to genome shuffling for yield improvement of deacetylmycoepoxydiene (DAM), an antitumor natural product with a novel chemical structure. After only two rounds of genome shuffling, four high-yield DAM-producing strains, namely G2-119, G2-448, G2-866, and G2-919, were obtained with the aid of activity screening and HPLC analysis. The results showed that the DAM yield in these four strains were 243-, 241-, 225-, and 275-fold, respectively, higher than that of the starting strain A123. This is the first time Monte Carlo simulation is introduced into the field of cell fusion and is also the first report on the optimization of genome shuffling focusing on the number of parental types in protoplast fusions
Xylan synthesized by Irregular Xylem 14 (IRX14) maintains the structure of seed coat mucilage in Arabidopsis
No full textEffects of surfactant micelles and surfactant-coated nanospheres on methane hydrate growth pattern. Chemical Engineering Science
No full textThe Miscanthus NAC transcription factor MlNAC9 enhances abiotic stress tolerance in transgenic Arabidopsis
No full textStable LATP/LAGP double-layer solid electrolyte prepared via a simple dry-pressing method for solid state lithium ion batteries
No full textIn this paper, a NASICON-type Li1.3Al0.3Ti1.7(PO4)(3) (LATP)/Li1.3Al0.3Ge1.7(PO4)(3) (LAGP) bi-layer structured solid state electrolyte was successfully prepared via a simple dry pressing and post-calcination method. By adjusting the sintering temperature for LAGP starting materials, a dense and smooth LATP/LAGP double-layer solid state electrolyte with no defects was obtained. This electrolyte sample exhibits a high electrical conductivity of 3.4 x 10(-4) S cm(-1) and a negligible electronic conductivity of 9.6 x 10(-9) S cm(-1) at room temperature. In addition, the LATP/LAGP electrolyte also shows an excellent stability in air as well as chemical stability against Li. Moreover, an assembled LiFePO4/LATP-LAGP/Li coin-type battery employing LATP/LAGP as the solid state electrolyte can be suitably charged and discharged at a current rate of 0.1C at room temperature, and its low charge-discharge capacities are mainly attributed to the high electrolyte/electrode interfacial resistance of the cell. These results suggest that the LATP/LAGP bilayer electrolyte can be an alternative electrolyte for all-solid-state lithium-ion batteries
Tuning the fused aromatic rings to enhance photovoltaic performance in wide band-gap polymer solar cells
No full textTwo novel wide band-gap polymers of PFT1 and PFT2 were designed as the alternative to P3HT in organic electronics, in which the fused aromatic rings were utilized and altered to tune their molecular co-planarity and photovoltaic performance in solar cells. As observed, although PFT1 exhibited strong inter-molecular interaction, slightly twisted molecular structure was observed, thus leading to an inferior PCE value of 1.95% in BHJ solar cells and holes mobility of 2.04 x 10(-2) cm(2) V-1 s(-1) in OFETs in contrast to its isomeric polymer PBTFT. On the other hand, when the fused thiophene rings was tuned to construct PFT2, much planar polymer backbone was achieved, finally leading to the maximum PCE value of 3.34% in polymer solar cells and much enhanced holes mobility up to 3.93 x 10(-2) cm(2) V-1 s(-1) in OFETs. Our results here further indicated that tuning the fused aromatic rings in polymer backbone could improve their charge transfer properties and enhance their photovoltaic performance in solar cells significantly. (C) 2016 Elsevier Ltd. All rights reserved
Influence of the functional groups of multiwalled carbon nanotubes on performance of ru catalysts in sorbitol hydrogenolysis to glycols
No full textDifferent functional groups (i.e. NH2, COOH, OH and nitrogen-doping) modified CNTs (denoted as
AMCN, CMCN, HMCN and NMCN, respectively) supported ruthenium catalysts (Ru/AMCN, Ru/CMCN,
Ru/HMCN and Ru/NMCN) were prepared by incipient wetness impregnation method. They were fully
characterized by XRD, TG, Raman, XPS, TPD and TEM to elucidate the relationship between the physical
property and their catalytic performance. TEM results shown that Ru particles were well dispersed on
the surface for all the samples with the size of 1.48–1.99 nm. The effects of functional groups of carbon
nanotubes (CNTs), nitrogen doping and base additive types on activity and selectivity of ethylene glycol
(EG) and propylene glycol (1,2-PD) were investigated. In addition, the activity and final products distribution
were much influenced by the properties of functional groups on CNTs and the type of metal cation
of the base promoters, which probably participated in the reaction for accelerating a retro-aldol reaction
for C C cleavage. Among the catalysts, Ru supported on AMCN exhibited the best catalytic activities and
glycols selectivities than on MCN, CMCN, HMCN and NMCN
Identification of an unexpected shunt pathway product provides new insights into tirandamycin biosynthesis
No full textTirandamycin K (7), the first linear 7,13;9,13-diseco-tirandamycin derivative, was isolated from the tamI (encoding the TamI P450 monooxygenase) disruption mutant strain (Delta tamI) of marine Streptomyces sp. 307-9. Its chemical structure with relative and absolute configurations was elucidated by a combination of extensive spectroscopic analyses and biosynthetic inferences. Structural elucidation of this unusual compound provides new insights into tirandamycin biosynthesis. Moreover, examination of the biological activity of 7 confirms the essential function of the bicyclic ketal ring for antibiotic activities of tirandamycins. (C) 2016 Published by Elsevier Ltd
Pickering Emulsion as an Efficient Platform for Enzymatic Reactions without Stirring
No full textTo address the current limitations of enzymatic reactions, we develop a novel strategy to conduct stirring-free biphasic enzymatic reactions. This strategy involves translation of a conventional biphasic enzymatic reaction to a water-in-oil (W/O) Pickering emulsion system by adding a small amount of solid particle emulsifier. In such a system, enzymes, for example, a Candida Antarctica lipase B (CALB), are compartmentalized within millions of micron-sized water droplets, while organic substrates are dissolved in the oil phase (outside the droplets). It was demonstrated that CALB-catalyzed hydrolysis kinetic resolution of racemic esters in the stirring-free Pickering emulsion system gave favorable reaction efficiency and enantioselectivity as compared to those for the conventional biphasic system under stirring conditions, which was due to the large reaction interfacial area and the short molecule distances created by the Pickering emulsion droplets. The specific activity was found to depend on the water droplet size, highlighting the importance of the presence of droplets in the reaction system. Moreover, the convenient and effective recycling of CALB could be achieved through simple demulsification by centrifugation. After 27 reaction cycles, the ee values of ester and alcohol were still as high as 87.5% and 99%, respectively, which significantly exceed those of the conventional biphasic reaction. The high recyclability may be attributed to avoiding stirring that often causes damage to the three-dimensional structure of enzymes. This study compellingly demonstrates that a Pickering emulsion is an innovative platform to efficiently process enzymatic reactions without need for stirring and immobilization