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Strategies to increase tolerance and robustness of industrial microorganisms

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Synthetic and Systems Biotechnology 2022年第1期7卷 533-540页

作者： marta Tous mohedano Oliver Konzock Yun Chen Division of Systems and Synthetic Biology Department of Biology and Biological EngineeringChalmers University of TechnologyGöteborgSweden

The development of a cost-competitive bioprocess requires that the cell factory converts the feedstock into the product of interest at high rates and ***,microbial cell factories are exposed to a variety of different stresses during the fermentation *** stresses can be derived from feedstocks,metabolism,or industrial production processes,limiting production capacity and diminishing *** stress tolerance and robustness allows for more efficient production and ultimately makes a process more economically *** review summarises general trends and updates the most recent developments in technologies to improve the stress tolerance of *** first look at evolutionary,systems biology and computational methods as examples of non-rational *** we review the(semi-)rational approaches of membrane and tran-scription factor engineering for improving tolerance *** further discuss challenges and perspectives associated with these different approaches.

关键词： Toxicity Novel synthetic biology tools Systems biology Genome-scale model Membrane engineering Transcription factor engineering

As-cast and extruded Mg-Zn-Ca systems for biodegradable implants:Characterization and corrosion behavior

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Journal of Magnesium and Alloys 2023年第3期11卷 1102-1120页

作者： Lara Moreno Endzhe Matykina Kiryl A.Yasakau Carsten Blawert Raul Arrabal marta mohedano Departamento de Ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense de Madrid28040 MadridSpain Department of Materials and Ceramic Engineering CICECO-Aveiro institute of materialsUniversity of Aveiro3810-193 AveiroPortugal Institute of Surface Science Helmholtz-Zentrum HereonMax-Planck Strasse 1Geesthacht 21502Germany

The aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg-Zn-Ca systems for biodegradable *** grain size and secondary phases were analyzed by optical microscopy,scanning electron microscopy,transmission electron microscopy,and X-ray *** kelvin probe force microscopy(SKPFM)was used to analyze the Volta potential values of the second *** corrosion performance of the three alloys was evaluated by electrochemical and hydrogen evolution methods inα-MEM with and without organic species(*** and inorganicα-MEM).Two strategies were followed to evaluate the influence of the pH on the corrosion behavior:daily solution replacement and CO_(2)flow based pH *** all the materials,the organic medium accelerates the corrosion *** pH maintained by CO_(2)flow through the medium results in considerably higher corrosion rates for all *** impact of pH is lesser on the as-cast alloys due to the barrier effect of the secondary phases,particularly pronounced in the Mg1Zn1Ca alloy which showed the lowest corrosion *** wrought Mg0.5Zn0.2Ca alloy that lacks the refined secondary phase network and exhibits high number of twins undergoes accelerated uniform corrosion under constant pH conditions.

关键词： MgZnCa Magnesium Biomaterials Characterization Corrosion

Quasi-in vivo corrosion behavior of AZ31B Mg alloy with hybrid MWCNTs-PEO/PCL based coatings

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Journal of Magnesium and Alloys 2022年第11期10卷 3217-3233页

作者： Morteza Daavari Masoud Atapour marta mohedano Hugo Mora Sánchez Juan Rodríguez-Hernández Endzhe Matykina Raul Arrabal Aboozar Taherizadeh Department of Materials Engineering Isfahan University of Technology84156-83111 IsfahanIran Departamento de Ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense28040 MadridSpain Institute of Polymer Science and Technology(CSIC) Polymer Functionalization GroupMadrid 28006Spain

This study investigated the effects of multi-walled carbon nanotubes(MWCNTs) and polycaprolactone(PCL) on the quasi-in vivo corrosion behavior of AZ31B Mg alloy treated by plasma electrolytic oxidation(PEO). Thin(~2 μm, PCTPCL4) and thick(~60 μm, PCTPCL6) PCL layers were applied only onto the MWCNTs-PEO coating(PCT) as it showed better corrosion performance. Findings reveal that incorporation of MWCNTs induced several structural and functional modifications in the PEO coating, such as increased roughness, a thicker inner barrier layer, and reduced ***-in vivo corrosion testing was carried out under controlled temperature, p H, and fluid flow in simulated body fluid(SBF) by electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. EIS results revealed that, after 48 h immersion, a diffusion process controlled hydration of the ceramic coatings. Comparison of the collected hydrogen after 15 days of immersion in the quasi-in vivo environment revealed that the PEO and PCT ceramic coatings decreased hydrogen generation by up to 74% and 91%, respectively, compared to non-coated ***6 coating exhibited the lowest amount of collected hydrogen(0.2 m L/cm^(2)). The thick PCL layer delayed the onset of substrate corrosion for at least 120 h, reducing the corrosion rate by 85% compared with the PCT.

关键词： AZ31B Mg alloy Plasma electrolyte oxidation(PEO) Multi-walled carbon nanotubes(MWCNTs) Quasi-in vivo condition Polycaprolactone(PCL)

添加CaO或Y的ZK40镁合金的腐蚀行为（英文）

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Transactions of Nonferrous Metals Society of China 2018年第3期28卷 427-439页

作者： Ricardo Henrique BUZOLIN marta mohedano Chamini Lakshi MENDIS Beatriz MINGO Domonkos TOLNAI Carsten BLAWERT Karl Ulrich KAINER Haroldo PINTO Norbert HORT Magnesium Innovation Centre Helmholtz-Zentrum Geesthacht Institute of Materials Science Joining and Forming Graz University of Technology Departamento de Ciencia de Materiales Facultad de Ciencias Químicas Universidad Complutense Brunel Centre for Advanced Solidification Technology Brunel University London Department of Materials Engineering University of Sao Paulo

研究了铸造ZK40、添加2%(质量分数)CaO和添加1%(质量分数)Y的ZK40镁合金的微观组织,并表征了金属间化合物相的形貌和分布。利用ZK40晶界处分散的金属间化合物颗粒,将添加了CaO或Y的ZK40的微观组织调整为沿晶界分布的金属间化合物的半连... 详细信息

研究了铸造ZK40、添加2%(质量分数)CaO和添加1%(质量分数)Y的ZK40镁合金的微观组织,并表征了金属间化合物相的形貌和分布。利用ZK40晶界处分散的金属间化合物颗粒,将添加了CaO或Y的ZK40的微观组织调整为沿晶界分布的金属间化合物的半连续网络结构。微观组织中没有检测到CaO,Ca存在于铸造过程中形成的金属间化合物Ca_2Mg_6Zn_3中。析氢和电化学交流阻抗谱分析显示,添加CaO后合金的耐腐性略有提高,而添加Y却对ZK40的耐腐蚀性有负面影响。浸泡试验结果显示,严重的局部腐蚀和沿金属间化合物的腐蚀对ZK40-Y合金的腐蚀过程有重要影响,而ZK40和ZK40-CaO合金的局部腐蚀不明显。ZK40合金中α-Mg基体中的显微偏析明显高于加CaO或Y的ZK40合金,这种作用结合合金表面形成了更加稳定的耐腐蚀层是ZK40-CaO合金的耐腐蚀性能提高的主要原因。

关键词：镁合金 ZK40 Y添加 CaO添加腐蚀行为