计算流体力学在模拟生化反应器中的应用研究

计算流体力学是生化反应器模拟研究的重要手段，简述了流体力学理论研究概况及其在搅拌式生物反应器，气升式生物反应器中的应用，并指出了进一步研究的方向。     

石油生物脱硫过程和反应器的研究进展

综述了近年来石油生物催化脱硫反应器的研究进展,介绍了搅拌釜反应器、气升式反应器、流化床反应器、固定床反应器等生物脱硫反应器的特点和应用状况,并分析其发展趋势.同时介绍了石油生物脱硫用于工业化的一般过程,提出了当前需要解决的问题并对今后的研究工作进行展望.     

气升式振荡环流反应器的数值模拟和结构优化

气升式振荡环流反应器（ARLR）作为一种新型的气升式环流反应器,能够有效地提高反应器的气含率和传质系数,并已得到生物发酵实验的验证。本文通过CFD的手段研究了反应器内的流动和传质状况,并利用CFD模拟和响应面分析相结合的方法,优化了反应器的结构参数,如高径比（H/D）、升液区降液区面积之比、导流筒高度等。经过实验测量,优化后的气升式振荡环流反应器与传统的气升式环流反应器相比,气含率提高了32%以上,传质系数提高了11%以上。结果表明,气升式振荡环流反应器作为生化反应器有着非常广阔的应用空间。     

大规模植物细胞培养生物反应器

讨论了植物细胞大规模培养的基本特性。根据分析比较了在植物细胞悬浮培养中通常使用的几种生物反应器,包括摇瓶,搅拌式反应器,气升式反应器,转瓶反应器以及带挡板的转瓶反应器,指出综合性能以气升式为最佳。此外还介绍了固定化植物细胞反应器以及生物膜反应器,讨论了大规模植物细胞培养反应器的选择原则。     

微气泡耦合生物反应器的研究进展

微气泡具有气液接触面积大、气体溶解速率快、上升速度慢和水中停留时间长等理化特征，非常适合于高气液传质效率需求的生物发酵过程。本文介绍了能够耦合生物反应器的几种微气泡发生装置，分别为微气泡分散器、微孔膜、流体振荡器耦合微孔膜和微气泡曝气搅拌桨；并简述了微气泡发生装置耦合搅拌式生物反应器、气升式生物反应器和生物膜反应器在生物反应过程的应用进展；最后回顾了二氧化碳微气泡在生物反应器的应用研究进展。指出微气泡耦合生物反应器的研究仍处于起步阶段，在放大规律和能耗方面仍处于研究空白。微气泡耦合生物反应器的发展对工业生物技术、石油化工、污水处理和资源再利用等的发展具有重要的意义。     

气升式反应器在发酵工业中的应用研究进展

气升式反应器是一种用于气液两相或气液固三相过程的接触式反应装置,简要综述了气升式反应器在发酵工业中的应用研究进展,按照集成强化的思路开发的气升式膜生物反应器被重点介绍。     

气升式反应器及其在生物技术中的应用

气升式反应器由于其优越的流体力学性能和广阔的应用前景，在传统化学工程和生物化工领域都是当前研究热点之一。本文简要介绍了气升式反应器的基本原理和特性，证介已有的主要研究结果、尚待解决的问题和趋势，以及气升式反应器在生物技术领域最重要的应用之一，即作为微藻养殖或某些植物细胞培养的光化生物反应器。     

环流反应器和搅拌槽传质特性的分析

本文测定了提升管为单段和提升管分为三段的气升式环流反应器中的液相体积氧传质系数，在螺带式搅拌桨区应器中测定了液相体积氧传质系数和功率消耗，实验体系为模拟生物发酵液非牛顿流体特性的核甲基纤维素水溶液，本文还从液相体积氧传质系数及单位液相体积的功耗所产生的氧传质效果方面对提升管不分段和提升管分为三段的气升式环流反应器与螺带式搅拌反应器进行了比较。     

盐藻在气升式光生物反应器中的光自养培养

在气升式光生物反应器中进行了盐藻培养特性的研究，确定了盐藻在2.5 L气升式光生物反应器中培养的适宜条件为：温度30℃，光强1.6 mW/cm2，盐浓度16%，通气量20 ml/min. 扩大到20 L反应器培养盐藻生长良好. 采用气升式光反应器培养盐藻生长快，周期短，4~7 d后即可进入稳定期；最终细胞密度大，最大为1.6?106 cells/ml；藻液中胡萝卜素含量高，最高含量32 mg/L.实验表明气升式光生物反应器适合于盐藻的培养.     

新型气升式环流反应器液相破碎效果的实验比较

针对石油废水生物降解过程中所遇到的水相、油相难以快速均匀混合的问题,通过对气升式环流反应器动力学原理的分析,在其基础上进行了改进,设计出新型气升式环流反应器,通过验证了推理设计的正确。在本新型气升式反应实验中,以煤油和水为介质,０．４ｍ＾３／ｈ的通气量是较佳的工作条件,证明了新型气升式反应器处理特殊条件液液两相均匀混合的可行性。     

A comprehensive study of lipase production by Yarrowia lipolytica CECT 1240 (ATCC 18942): from shake flask to continuous bioreactor

BACKGROUND: Lipases are commercially important enzymes, and the development and optimization of their production processes are of great interest. The diversity of behaviours between strains stresses the need for research on this topic, especially when bioreactor culture is considered. The study of a continuous operating mode is especially attractive, since very scarce information is available on its application to microbial lipases production. RESULTS: Lipase production in submerged cultures of Yarrowia lipolytica CECT 1240 (ATCC 18 942) has been investigated. Significant lipolytic activity (over 700 U dm^?3), mostly extracellular and membrane‐bound, was obtained in shake flasks using medium supplemented with olive oil. The culture was carried out in air‐lift and stirred tank bench‐scale bioreactors and the latter was selected. The influence of aeration and agitation rates was assessed in batch cultures, and agitation from 400–700 rpm and low aeration rates (i.e. 0.2 vvm) are recommended. Batch, fed‐batch and continuous operation were investigated, and regular enzyme production (up to 600 U dm^?3) was achieved with the latter. CONCLUSION: Lipase production by the selected strain was successfully carried out in shake flasks and bench‐scale bioreactors. After studying batch, fed‐batch and continuous processes, continuous culture in a stirred tank bioreactor was found best in terms of regular enzyme production, exceptionally good operational stability and good fitting of the results to mathematical models. Copyright © 2009 Society of Chemical Industry     

Culture Conditions and Investigation of Bioreactor Configurations for Lipase Production by Rhizopus oryzae

Lipolytic enzymes are the subject of great industrial and academic interest. For this reason, a detailed study of lipolytic enzyme production by the fungus Rhizopus oryzae is tackled, and several steps from plate to shake flasks and bioreactor cultures are investigated in order to propose an optimized strategy to perform the biological process. The suitability of several lipidic compounds and surfactants is assessed. Triton X‐100 (5 g/L) gives the highest activities with a maximum value of 6320 U/L which is 10‐fold the value attained in cultures without addition of lipidic compounds. As there are almost no studies on bench‐scale bioreactors, two bioreactor configurations, stirred tank and air‐lift, are investigated to determine the most suitable one to carry out the biological reaction. It is demonstrated that the lipolytic activity is strongly enhanced when a stirred‐tank bioreactor is used with a maximum value of 3521 U/L within two days which is clearly higher than the values produced by other recently reported species.     

Coupling of mixing and microbial kinetics for evaluating the performance of bioreactors

The effect of the dynamics of the mixing process in mechanically stirred bioreactors upon their performance has been investigated by using a circulation-model for flow of fluid and a two-environment-model to account for the extent of micromixing in the vessel. With the help of an empirical kinetic model to depict the oxidative and the fermentative growth of bakers' yeast, experimentally observed effects of initial sugar concentrations upon critical dilution rates in continuous cultures of this system could be explained. Effect of different scales of operation upon productivities of fed-batch cultures of bakers' yeast could also be satisfactorily predicted. A discrete simulation procedure was found to be a convenient tool in coupling the two-environment circulation-model of mixing with kinetics of microbial reactions.     

Influence of impeller type on hydrodynamics and gas‐liquid mass‐transfer in stirred airlift bioreactor

The influence of impeller type in a mechanically stirred airlift bioreactor was analyzed in relation to the non‐Newtonian viscous fluids. The agitation was carried out through a marine impeller (axial impeller) and a paddle impeller (radial impeller) located along with the gas sparger in the region comprised by the riser. The bioreactor was sparged with air under different velocities (0.036–0.060 m s^?1). Carboxymethylcellulose 1.94% and xanthan 1.80% were used as a fluid model. The gas holdup and volumetric mass‐transfer coefficient increased in up to five and three times, respectively, when compared to a conventional airlift bioreactor; however, better results were obtained when the straight paddle impeller type was used. The results suggest that the studied bioreactor can be used successfully in viscous fluid, and it can be more efficient than conventional airlift bioreactors. The results obtained suggest the use of radial impellers. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3159–3171, 2015     

Initial power measurements for a family of novel vertical-wheel bioreactors

The purpose of this investigation was to develop an initial set of Power number versus Reynolds number results for a family of vertical-wheel bioreactors. These bioreactors are increasingly being used for the manufacture of cells for cell therapy but have not been characterized according to this approach. A novel gravimetric method to measure power was used, and the validity of this method was assessed by measuring power for a standard stirred tank bioreactor with a Rushton impeller. The results of the gravimetric method were found to closely match those derived from traditional methods. The validated method was then used to measure the power draw and develop an initial set of Power number versus Reynolds number results for a family of vertical-wheel bioreactors.     

搅拌生物反应器的结构模型、放大及搅拌器改型

搅拌生物反应器（ＳｔｉｒｒｅｄＢｉｏｒｅａｃｔｏｒ－ＳＢＲ）是最重要的生物反应器，随着生物高新技术的发展，在医药、食品、化工及环境等领域对其提出了更高的要求。为此详细评述了最近１０年在ＳＢＲ的结构模型、放大及搅拌器改型方面的进展及存在的问题，特别强调了ＳＢＲ性能研究的总体战略及具体的方法步骤。还就本学科发展的研究工作提出了建议。     

翼形桨在气液固三相搅拌反应釜中的混合性能

<正>机械搅拌槽中高速旋转的叶轮产生的排出流中,径向速度主要用于气体的剪切分散,而其轴向速度是固体悬浮和液相轴向混合的主要动力。三相体系的混合不仅要求叶轮具有较强的径向剪切分散能力,而且要有一定的轴向混合能力,以此达到对气体和固体的同时分散。理想的混合水平不仅要求达到二者在宏观上的均匀,而且在微观混合上也要达到一定的均匀度,为此对搅拌桨的设计提出了较高的要求。在气液二相的混合操作中比较多的采用了盘式涡轮桨,而在液固二相的混合操作中比较多的使用螺旋桨,这都是为了利用各自不同的混合优势。涉及到气液固三相混合,由于气体和固体的分散是一个相互制约的问题,完全的径向     

Effects of supplementation of succinic acid on the production and molecular weight distribution of exopolysaccharides by Antrodia camphorata in batch cultures

The effects of organic acid supplementation on both yields and molecular weight distributions of exopolysaccharide (EPS) of Antrodia camphorata were investigated in shaker flasks and air‐lift bioreactors. In the shaker flask study, five out of six organic acid‐supplemented cultures showed negative effects on cell growth, the exception being pyruvic acid‐supplemented culture; lower number average molecular weights (Mn) of EPS were obtained in all the supplemented cultures. EPS production was enhanced by 31% due to the addition of succinic acid. Optimum product yield was obtained between 2.0 and 3.0 g dm^?3 succinic acid; however, the specific production of EPS increased monotonically as succinic acid concentration was increased from 0 to 5 g dm^?3. Enhancement of EPS yield by 28% and a higher Mn of EPS (around 310 kDa) due to the addition of succinic acid were also demonstrated in an air‐lift bioreactor. In addition, a novel fermentation process resistant to EPS degradation is proposed, based on the inhibition of β‐glucanase activity by the supplementation with succinic acid. Copyright © 2004 Society of Chemical Industry     

Oxygen Mass Transfer Rate in a Pressurized Lab‐Scale Stirred Bioreactor

Oxygen mass transfer from air to the liquid phase in bioreactors with aerobic cultures has long been a serious impairment to the productivity of various bioprocesses. An increase of the oxygen mass transfer rate (OTR) can be the key to overcome oxygen limitation. The influence of higher air pressure on OTR was measured and a significantly enhanced OTR could be obtained. The oxygen volumetric mass transfer coefficient (k_La) was described by a function of the air pressure in a stirred lab‐scale pressurized bioreactor. The correlation obtained proved that k_La slightly decreased with higher air pressure, following a power function.     

低高径比外循环气升式生物反应器带渣发酵生产有效霉素

Fermentation experiments to produce validamycins from crude substrates by Streptoniyces hygroscopi-cus were carried out in an external-loop airlift bioreactor (0.0115 m3 ) with a low ratio of height to diameter of the riser of 2.9 and a ratio of riser to downcomer diameter of 6.6. The influences of gas flow rate and liquid volume on fermentation of validamycins were investigated. Comparisons of validamycin fermentation were made among the external-loop airlift bioreactor, a mechanically stirred tank bioreactor (0.010m3 ) and shaking flasks. Under the same operation conditions including fermentation medium composition, inoculum ratio and culture temperature, the fermentation time in the external-loop airlift bioreactor (45 h) was shorter than that in the shaking flasks (100 h) and the same as that in the mechanically stirred tank bioreactor. After a total fermentation time of 45 h under optimized operation conditions, average validamycin concentration obtained in the external-loop airlift bioreactor was