高校化学工程学报论文格式.doc

页边距：上: 2.65厘米; 下: 2.5厘米; 左、右: 2.47厘米; 装订线: 0厘米；页眉: 1.9厘米; 页脚: 2.2厘米应用于：整篇文档； 纸型：A4； 版式：新建页；奇偶页不同和首页不同都打“”文档网格：(指定行网络和字符网络)每行: 44个字符; 每页: 42行; 栏数：1； 应用于：整篇文档 文章编号：1003-9015(2003)01-剪切应力对红豆杉细胞悬浮培养的影响及CFD模拟研究收稿日期: 2001-12-27; 修订日期: 2002-07-08。基金项目：国家自然科学基金(20176038)作者简介：商桂敏(1979-)，女，山东德州人，天津大学博士生。 通讯联系人：元英进；E-mail: 商桂敏, 施中东, 未作君, 元英进(天津大学化工学院制药工程系, 天津 300072)摘 要：在同轴圆筒装置的均匀剪切场中研究了不同剪切应力(0.16, 0.46, 0.78Pa)对悬浮培养的南方红豆杉细胞生理的短期影响。结果表明剪切应力为0.160.46Pa时，有利于细胞的生长和初生代谢；剪切应力为0.460.78Pa时, 有利于细胞的次生代谢；另一方面利用计算流体力学(CFD)对20L生物搅拌釜(45-斜向上桨(45-PBT)，桨距为(1/3)T的流场进行了三维模拟，获得搅拌釜内部的剪切场。结果表明搅拌釜内剪切应力分布极不均匀, 且主要集中在搅拌桨区和尾流区，约为主流区和挡板区值的35倍，有时甚至高达7倍。通过将实验结果和CFD模拟相结合，预测了20L生物搅拌釜剪切应力对南方红豆杉细胞生理的影响。表明当搅拌转速小于150 rmin-1时，搅拌釜内相应的剪切应力有利于细胞的生长和初生代谢；而当搅拌转速大于200 rmin-1时，则不宜于南方红豆杉细胞的培养。关键词：计算流体力学(CFD); 剪切应力; 植物细胞悬浮培养; 均匀剪切场中图分类号：Q813.11 文献标识码：A （本刊刊出的文章均标识为A）Effects of Shear Stress on Suspension Cultures of T.chinensis var.mairei Cellsand its CFD SimulationSHANG Gui-min, SHI Zhong-dong, WEI Zuo-jun, YUAN Ying-jin(Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology,Tianjin University, Tianjin 300072, China)Abstract: A uniform shear stress field was generated by using a co-axial cylinder apparatus to study the short-period effects of shear stress (t = 0.16, 0.46, 0.78Pa) on the Taxus cells physiology. Results showed that the cells grew well and the primary metabolism was vigorous when 0.16Pat 0.46Pa, and that the cells had the tendency to accumulate more secondary metabolites when 0.46Pat 0.78Pa. Meanwhile, a 3-D CFD simulation of the hydrodynamics characteristics in a 20L impeller stirred bioreactor (45-upward Pitched-Blade-Turbine, (1/3) T of the off-bottom clearance) was conducted to obtain the shear stress field inside the reactor. It could be seen that the strength of the shear stress was inhomogeneous and mainly concentrated in the impeller swept and wake flow regions, which was more than 7 times higher than that in the bulk and baffle regions. By combining the experimental results and CFD simulations, the effects of the shear stress on Taxus cells cultured in impeller-stirred reactors were predicted. Results showed that the impeller agitating speed less than 150 rmin-1 is beneficial to cell growth and primary metabolism. Whereas when the agitating speed is higher than 200 rmin-1, the magnitude of the average shear stress in the reactor will be too big and become unsuitable to cell culture. Key words: computational fluid dynamics (CFD); shear stress; suspension cultures of plant cells; uniform shear stress field1 前 言 图1 实验装置流程图 Fig.1 The flow chart of experiment apparatus 1. C3H6 steel bottle 2. pressure reducing valve 3. cut-off valve 4. pressure stabilization valve 5. flow stabilization valve 6. rotermeter 7. O2 steel bottle 8. N2 steel bottle 9. H2 steel bottle (carrier gas) 10. preheater 11. 6-way valve group 12. reactor 13. temperature controller 14. gas phase chromatograph 15. data processing system 16. exhaust absorption bottle植物细胞悬浮培养在一些小型的反应器中已经取得了成功，但是在较大的生物搅拌釜中仍然很难形成突破，一个重要的问题就是搅拌釜内搅拌与通气产生的剪切应力对植物细胞的生长和代谢有显著的影响。剪切应力有两方面的影响：一方面表现为积极影响，如增加透气、保持良好的混合状态和细胞分散性1。在适合条件下，可以提高细胞产率和增加次生代谢产物产量。而多数情况下则呈现负作用，造成植物细胞损伤，影响细胞形态、代谢等。为寻找一种最佳状态，人们研究了各种搅拌桨和不同转速情况下所产生的剪切场对细胞生理状态的影响25。然而由于实验手段的限制，这些研究无法区分搅拌釜中各个区域流体剪切应力的差异，往往是将其简单地当作搅拌转速的单值函数，这一简化使得搅拌釜内剪切应力大小与细胞生理变化之间的定量关系仍不明确。因此人们引入同轴圆筒装置, 其产生的剪切场被认为是均匀的6。 (1)2 实验(材料和方法)2.1 细胞系Fe2+ concentration C/mgL-1t / h图2 Fe2+浓度随时间的变化关系Fig.2 The chang of Fe2+concentration during reaction051015202502004006008001000 t / min图3 不同催化剂载体降解苯酚的比较Fig.3 Phenol degradation rate for different catalyst system05101520253035020406080100 silica gel D001 resin Na-X zeolite Na-Y zeolite h / % 细胞株系采用南方红豆杉(T.chinensis var.mairei T)细胞，由中国科学院植物研究所提供。细胞株系在改良B5培养基上培养，具体条件见文献7。表1 搅拌釜内各区域的划分Table 1 Details of the split regionsRegionr-coordinatez-coordinateVolume ratio / %Impeller00.05m0.080.12m5.61Wake flow0.050.13m0.080.18m18.41Baffle0.130.15m00.3m11.83BulkThe rest64.15符号说明：A 膜器传质总面积, cm2Qorg 有机相体积流量, mLmin-1de 壳程的当量直径, cmuw 水相有机相流速, cms-1Dw 苯酚在水相的扩散系数, cm2s-1uo 有机相流速, cms-1Do 苯酚在有机相中的扩散系数, cm2 s-1d 中空纤维膜的膜厚, mmKw 基于水相的总传质系数, cms-1em 中空纤维膜的孔隙率L 膜器有效长度, cmj 膜器的装填因子m 体系的分配系数tm 中空纤维膜的弯曲因子Qaq 水相体积流量, mLmin-1no 有机相运动粘度, cm2 s-1参考文献: 1 Leckie F, Scragg A H, Cliff K R. Effect of bioreactor design and agitator speed on the growth and alkaloid accumulation by cultures of Catharanthus roseus J. Enzyme Microb Technol, 1991, 13(2): 296-305. 2 Hooker B S, Lee J M, An G. Cultivation of plant cells in a stirred vessel: Effect of impeller design J. Biotechnol Bioeng, 1990, 35: 296-304. 3 Wanger F, Volgelmann H. Plant Tissue Culture and its Biotechnological Application M. Berlin: Springer-Verlag, 1977. 245-255. 4 Scragg A H, Allan E J, Leckie F. Effect of shear on the viability of plant cell suspensions J. Enzyme Microb Technol, 1988, 10(2): 361-367. 5 Meijer J J, ten Hoopen H J G, van Gameren Y M. Effects of hydrodynamic stress on the growth of plant cells in batch and continuous culture J. Enzyme and Microb Technol, 1994, 16(3): 467-477. 6 Hooker B S, Lee J M, An G. Response of plant tissue culture to a high shear environment J. Enzyme Microb Technol, 1989, 11(3): 484-490. 7 Zhang C P, Li C, Yuan Y J. Effects of fungal elicitor on cell status and taxol production in cells suspension cultures of Taxus chinesis var. Mairei J. Chinese J Biotechnol, 2001, 17(4): 436-440. 8 Towill LE, Mazur P. Studies on the reduction of 2,3,5-triphenyltetrazolium chloride as a viability assay for plant tissue cultures J. Can J Bot, 1975, 53: 1097-1102. 9 Adam A, Farkas T, Somlyai G et al. Consequence of O2-generation during a bacterially induced hypersensitive reaction in tobacco: Deterioration of membrane lipids J. Physiological and Molecular Plant Pathology, 1989, 34(1): 13-26.10 Chen S Y, Huang S Y. Shear stress effects on cell growth and L-DOPA production by suspension culture of Stizolobium hassjoo