Techniques for oxygen transfer measurement in bioreactors pdf

First, the most used measuring methods are revised. Survey of measurement techniques for gasliquid mass transfer coefficient in bioreactors survey of measurement techniques for gasliquid mass transfer coefficient in bioreactors gogate, parag r pandit, aniruddha b. If oxygen is limited, cell growth and product formation can be affected. Combination of online ph and oxygen transfer rate measurement in shake flasks by fiber optical technique and respiration activity monitoring system ramos sensors. For kla value determination the static gassing out method has been used, which is based on measuring the increase of dissolved oxygen concentration in broths. Shaking bioreactors are the most frequently used reactor system for screening and process optimization on a small scale.

Recently reported findings for oxygen transfer, power input, outofphase operation, hydromechanical stress. In the absenceofmicrobialcells,theotrcanbeestimated by the oxygen absorption rate of a sodium sulfite. In this work a simplified version of the same method is discussed. The microbial growth in a bioreactor depends upon the oxygen transfer rate otr. The second term describes the oxygen consumption due to the biological activity. Easy to use and reliable technique for online dissolved. Bioreactors are important inevitable part of any tissue engineering te strategy as they aid the construction of threedimensional functional tissues. Hydrogen peroxide use in bioreactors engineering bibliographies in harvard style. Chattaway and stephanopoulos 20 have applied kalman filter for.

Survey of measurement techniques for gasliquid mass transfer coefficient in bioreactors gogate, parag r pandit, aniruddha b. In the present study, all oxygensensitive nanoparticle concentrations are below 1 g l. Particularly, oxygen represents one of the most important factors for life, and the understanding and control of its mass transfer in bioreactors is one of the most challenging problems in the industry. Recently reported findings for oxygen transfer, power input, outofphase operation, hydromechanical. Oxygen transfer abstract 193 words this practical was carried out with the aim of determining the kla value for oxygen transfer as well as examining the relationship between kla and other fermenter variables like speed of the impeller and air flow rate, thereby calculating the values. Oxygen mass transfer in a stirred tank bioreactor using. A bioreactor is basically a device in which the organisms are cultivated to form the desired products.

Results are consistent with our mathematical model and give insight into the conditions under which flux of oxygen through pdms into the microchannels will or will not contribute significantly to oxygen delivery to cells and also provide a design tool to manipulate and control oxygen for cell culture and device engineering. Techniques for oxygen transfer measurement in bioreactors are discussed by suresh et al. The medium flows back in the down comer and completes the cycle. Potential errors in conventional dot measurement techniques. As one of the key variables, temperature must be tightly regulated to ensure reliable and consistent data is obtained across the many different processes that use bioreactors. Airlift bioreactors are commonly employed for aerobic bioprocessing technology. The otr is widely used to study the growth behavior of microbial and plant cell cultures. However, there is a limit to the rate of oxygen transfer than can be achieved, and oxygen requirement is generally the limiting factor in highcelldensity growth stratton et al. The vessel should be equipped with stirrers or mixers to ensure mass transfer processes occur efficiently. The residence time of the gas in dispersion tr, and average bubble rising velocity ub in the riser,were calculated using eqs. David2 1macdiarmid institute for advanced materials and nano technology, department of electrical and computer engineering, university of canterbury, private bag 4800, christchurch, new zealand 2centre for bioengineering, department of mechanical engineering, university of canterbury, private bag 4800. Figure 1c shows a schematic crosssection of the device based on a glass. The oxygen transfer rate otr is influenced by the physical properties of the gas and liquid, operational conditions, geometric parameters, and the consumption rate by the cells.

Some of the critical engineering issues in the shake bioreactor were reported 8. Simultaneous determination of oxygen consumption rate. Classification of bioreactors there are numerous types of bioreactors batch, sequence, continuously stirred tanks, anaerobic contact processes, anaerobic filters, etc. Correct measurement and subsequent estimation of the volumetric mass transfer coefficient is a crucial step in the design. Special difficulties are associated with measuring oxygen transfer rates and kla in large fermenters. Survey of measurement techniques for gasliquid mass.

The heart of the fermentation or bioprocess technology is the fermentor or bioreactor. Oxygen transfer rate an overview sciencedirect topics. A high hydrostatic pressure generated at the bottom of the reactor increases the solubility of o 2 in the medium. Feb 20, 2014 the heart of the fermentation or bioprocess technology is the fermentor or bioreactor. It should be provided with inoculation point for aseptic transfer in inoculum. Oxygen control for bioreactors and invitro cell assays v. Correct measurement and subsequent estimation of the volumetric mass transfer. This technique may be used for timelapse studies hours or days without disturbing the setup, and for imaging of spatial oxygen distributions. Results from a dissolved oxygen time course experiment show the o2 transfer speed of the 150ml frustoconicalbottomed culture vessel on a shaker platform with a 100rpm orbital shaking speed. Due to high efficiency, airlift bioreactors are sometimes preferred e. With an increasing organic fraction, the mass transfer coefficient decreases, whereas.

Oxygen transfer coefficient in pneumatically agitated bioreactors. Oxygen transfer rate bioreactors scaleup microbial processes gasliquid interface in aerobic bioprocesses, oxygen is a key substrate. Oxygen transfer, mixing time and gas holdup characterization. Oxygen transfer, mixing time and gas hold up characterization in a hybrid bioreactor 3 was 0. Determination of the volumetric oxygen transfer coefficient kla plays an important role in the design and characterization of bioreactors. This technique does not require the measurement of dissolved oxygen concentrations but relies. In this work, a critical distinction is made between the oxygen mass transfer coefficient, k l a, and the oxygen mass transfer rate. The rate of oxygen transfer from air bubble to the liquid phase may be described by the equation. Oxygen mass transfer characteristics for various twin and singleimpeller systems were investigated for 6 configurations in a vessel with 10 cm of inner diameter and working volume of 1. The mass balance for the dissolved oxygen in the wellmixed liquid phase, in the absence of biomass or with nonrespiring cells when biochemical reactions do not take place, can be established as follows. A bioreactor system comprises a bioreactor, sensors and actuators, a control system and software to monitor and control the conditions inside the bioreactor. There are many techniques for measuring oxygen concentration and otr in bioreactors. Since the ultimate aim of a bioreactor is to create a biological product, the engineering parameters, for example, internal and external mass transfer, fluid velocity, shear stress, electrical current distribution, and so forth, are worth to be.

Bioreactors are expensive due to measurement and control needs of the. Oxygen transfer is often achieved through the use of a gas sparger fitting that bubbles compressed. Oxygen transfer, mixing time and gas hold up characterization in a hybrid bioreactor 5 d d l h h. A bioreactor is a container that provides desirable conditions for biochemical reactions, these equipments are used in many biotechnological operations and its use is essential.

Jun 01, 2012 shaking bioreactors are the most frequently used reactor system for screening and process optimization on a small scale. Bioreactors have been used for hundreds of years to treat sewage and other odoriferous, waterborne waste. Here a combination of the online oxygen transfer rate otr measurements in the ramos device with an online, fiber optical ph measurement is presented. About sixty years ago, europeans began using bioreactors to treat. Advances in monitoring and state estimation of bioreactors. The mass transfer coefficient k l a determines the magnitude of the otr. The concept is simple, but the execution can be quite complicated. Traditionally, three methods have been widely used to measure rates of oxygen transfer. Furthermore, while many simulation studies of airlift reactors have been reported for newtonian fluids, there is a lack of numerical simulation study of airlift bioreactors incorporating the nonnewtonian fluid rheology commonly encountered in bioprocesses.

They can be conveniently classified into three major types based on the presence or absence of oxygen and requirement of stirring. Bioreactor scaleup and oxygen transfer rate in microbial. Oxygen transfer in fermentation systems 1 proportional to the product of a transfer coefficient and the trans ferring area at the gasliquid interface, i. Chisti department of chemical engineering, university of almera, 04120 almera. The methodology is based on modifications of the classical dynamic gassing in method and the steadystate mass balance method for obtaining the valueskla and our, respectively. Bioreactors use microbes to remove pollutants from emissions by consuming the pollutants. Zirconia, electrochemical, infrared, ultrasonic and laser cells are used to measure oxygen concentration in the liquid medium.

Jan 07, 20 in such cases, the volumetric oxygen transfer coefficient, k l a, must be known in order to carry out the design and scale up of bioreactors. Oxygen mass transfer in bioreactors involves many masstransfer resistances. Request pdf techniques for oxygen transfer measurement in bioreactors. This issue is compounded by the very low solubility of molecular oxygen in aqueous solutions popovid et al. The otr is widely used to study the growth behavior of. Constant further development of this measurement technology and the possibility to manufacture such sensors in various designs even for singleuse applications have led to new stateoftheart devices for the biotechnology sector. Chisti department of chemical engineering, university of almer. The aim of this study was to develop an optical approach for measuring the oxygen mass. Survey of measurement techniques for gasliquid mass transfer coefficient in. Their success can be attributed to their simple and functional design, which make shaking systems suitable for a large number of costefficient parallel experiments. The techniques vary according to the accuracy required and have advantages and disadvantages depending ontheavailability ofthenecessaryanalyticalinstruments and material and labor costs 12. Abstract oxygen is the most essential requirement for aerobic bioprocesses. Types of bioreactors fermenters linkedin slideshare.

Sampling valve for withdrawing a sample for different tests. A pressurecycle fermenter with large dimensions constitutes a tower bioreactor fig. Oxygen mass transfer rate in a pressurized labscale. Applications of gasliquid transport with reaction gasliquid mass transfer in bioreactors microbial cells often grown aerobically in stirred tank reactors oxygen supply is often limiting x d. Survey of measurement techniques for gasliquid mass transfer.

Oxygen control for bioreactors and invitro cell assays. For productionscale bioreactors, a better representation of oxygen transfer may be achieved using a. Survey of measurement techniques for gasliquid mass transfer coefficient in bioreactors. In combination with the liquid jet momentum, which characterizes the hydroejector, a scaleup correlation with the oxygen transfer rate as scaleup criterion is proposed, independent of the type of hydroejector and the reactor configuration. Quantitative measurement and control of oxygen levels in. The oxygen transfer rate otr must be known, and if possible predicted to.

Dec 12, 2006 results are consistent with our mathematical model and give insight into the conditions under which flux of oxygen through pdms into the microchannels will or will not contribute significantly to oxygen delivery to cells and also provide a design tool to manipulate and control oxygen for cell culture and device engineering. A new approach is proposed for the simultaneous determination of the volumetric oxygen transfer coefficient kla and the oxygen uptake rate our in bioreactors. The methods described for oxygentransfer measurement are. The mass transfer coefficient kla determines the magnitude of the otr. The commonly used scaleup criteria are investigated for their applicability in the case of hydroejector reactors. Bioreactor scaleup and oxygen transfer rate in microbial processes. The oxygen transfer rate otr must be known, and if possible predicted. Enhancement of oxygen mass transfer in stirred bioreactors using oxygenvectors. Aeration step method for kla measurement under growth conditions. To demonstrate the application of the combined measurement techniques, escherichia coli cultivations were performed and on.

As the bioreactor aims to create a desired biological product, it is important to closely monitor the reaction parameters like internal and external mass transfer, heat transfer. Oxygen transfer characteristics of miniaturized bioreactor systems. A novel method of simulating oxygen mass transfer in two. Emphasis is placed on techniques that provide compatibility with commonly used microfabrication processes, while allowing for laterallyresolved measurement of oxygen in a reusable, lowcost setup. Do concentration is usually measured by a polarographic do probe allman, 2007. Control and measurement of oxygen in microfluidic bioreactors. The mass transfer of oxygen transfer is often a limiting factor in bioreactors. The rate of oxygen transfer to the liquid phase can be controlled by varying the impeller speed.

Furthermore,theuseofparylene c coating in the pdms devices can add additional diffusive resistance to the oxygen transfer from the ambient air owing. Over the past decade, the application of chemical optical sensors for bioprocess monitoring has gradually taken roots. The effects of such reaction variables on biological cultures and analysing. In this study, a miniature stirred tank bioreactor was designed for treatment of waste gas containing benzene, toluene and xylene. At the top of the riser, with expanded top reduces pressure and facilitates expulsion of co 2. It should have sensors to monitor and control the fermentation process.

Bioreactors classification and types biotech articles. Monitoring of cell density requires manual sampling from reactors. Techniques for oxygen transfer measurement in bioreactors. Simultaneous determination of oxygen consumption rate and volumetric oxygen transfer coefficient in pneumatically agitated bioreactors j. Advances in shaking technologies, trends in biotechnology. Mar 25, 2009 the microbial growth in a bioreactor depends upon the oxygen transfer rate otr. Similarly, equations 5, 6, 6a, and 7 can be written for those systems where the overall oxygen transfer rate is controlled by the resistance at the liquidcell boundary. Oxygen transfer to the liquid phase is perhaps the most important. Simultaneous determination of oxygen consumption rate and. Advances in the design of bioreactor systems bioreactors are closed systems in which a biological process can be carried out under controlled, environmental conditions. Abstractbioreactor engineering allows modeling the conditions of real life biological processes. Mass transfer, bioreactor, volumetric oxygen transfer coefficient introduction. Among these, resistance of the gasliquid interfacial area a and liquid film resistance kl are usually the ratelimiting steps for transfer of oxygen to or from the bulk of the liquid phase. An overview of fermenter and the design considerations to.

Oxygen mass transfer rate in a pressurized labscale stirred. Optical sensors are better alternatives to measure oxygen concentration in small bioreactors. As a final demonstration, we assembled a rolling wheel dipped into table 1. Optical approach for measuring oxygen mass transfer in. With respect to the original dpm, the simplified version greatly simplifies data treatment.