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Effects of rolling-cutting processing parameters on micro-grooved strips forming
Baoyu Zhang,Xianqi Fan,Guocheng Shi,Yang Zhou,Di He,Wenjun Deng 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1
High heat flux density in the micro-electronics field urges the demand for functional surface for heat transfer. Micro-grooved surface is the classical heat transfer surface because of the larger specific area and better inducement of turbulence. A novel micro-grooved surface manufacturing process, the rolling-cutting process, is proposed to produce microgrooved strips. Experiments are conducted to analyze the influence of processing parameters on the strips forming. The optimal combination of processing parameters is given to attain the micro-grooved strips with higher fins height and thinner base thickness. Additionally, the obtained strips are of three-dimensional structures with serrated bulges at the top. The difference between the material flow of serrated bulges and strip base is discussed, and the forming of serrated bulges is mainly due to inhomogeneous sinuous material flow.
Dandan Zhang,Nan Liang,Zhongping Shi,Liming Liu,Jian Chen,Guocheng Du 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.2
This manuscript aimed at increasing the production of α-ketoglutarate by the multi-vitamin auxotrophic yeast Torulpsis glabrata CCTCC M202019. The carbon flux was redistributed from pyruvate to α-ketoglutarate node by manipulating the specific activity of pyruvate dehydrogenase complex (PDH), pyruvate carboxylase (PC), pyruvate decarboxylase (PDC), and α-ketoglutarate dehydrogenase complex (KGDH). By proper increase of PDH, PC, and PDC activities, α-ketoglutarate in fermentation broth could be accumulated to the levels of 17.1 g/L, 21.6 g/L, and 31.2 g/L, respectively. In addition, decrease in the specific activity of KGDH also resulted in an enhanced α-ketoglutarate synthesis. With a proposed combinational enzymes regulation strategy, the highest α-ketoglutarate concentration of 37.7 g/L was achieved This manuscript aimed at increasing the production of α-ketoglutarate by the multi-vitamin auxotrophic yeast Torulpsis glabrata CCTCC M202019. The carbon flux was redistributed from pyruvate to α-ketoglutarate node by manipulating the specific activity of pyruvate dehydrogenase complex (PDH), pyruvate carboxylase (PC), pyruvate decarboxylase (PDC), and α-ketoglutarate dehydrogenase complex (KGDH). By proper increase of PDH, PC, and PDC activities, α-ketoglutarate in fermentation broth could be accumulated to the levels of 17.1 g/L, 21.6 g/L, and 31.2 g/L, respectively. In addition, decrease in the specific activity of KGDH also resulted in an enhanced α-ketoglutarate synthesis. With a proposed combinational enzymes regulation strategy, the highest α-ketoglutarate concentration of 37.7 g/L was achieved
( Haibo Yuan ),( Yanfeng Liu ),( Xueqin Lv ),( Jianghua Li ),( Guocheng Du ),( Zhongping Shi ),( Long Liu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12
The compound 2,5-furandicarboxylic acid (FDCA), an important bio-based monomer for the production of various polymers, can be obtained from 5-hydroxymethylfurfural (HMF). However, efficient production of FDCA from HMF via biocatalysis has not been well studied. In this study, we report the identification of key genes that are involved in FDCA synthesis and then the engineering of Raoultella ornithinolytica BF60 for biocatalytic oxidation of HMF to FDCA using its resting cells. Specifically, previously unknown candidate genes, adhP3 and alkR, which were responsible for the reduction of HMF to the undesired product 2,5- bis(hydroxymethyl)furan (HMF alcohol), were identified by transcriptomic analysis. Combinatorial deletion of these two genes resulted in 85.7% reduction in HMF alcohol formation and 23.7% improvement in FDCA production (242.0 mM). Subsequently, an aldehyde dehydrogenase, AldH, which was responsible for the oxidation of the intermediate 5-formyl-2-furoic acid (FFA) to FDCA, was identified and characterized. Finally, FDCA production was further improved by overexpressing AldH, resulting in a 96.2% yield of 264.7 mM FDCA. Importantly, the identification of these key genes not only contributes to our understanding of the FDCA synthesis pathway in R. ornithinolytica BF60 but also allows for improved FDCA production efficiency. Moreover, this work is likely to provide a valuable reference for producing other furanic chemicals.