An improved method for determination of the volumetric oxygen transfer coefficient in fermentation processes

✍ Scribed by Xiao-Ming Yang; Zhuo-Xiong Mao; Shou-Zhi Yang; Wei-Ying Mao

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 288 KB
• Volume: 31
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.260310913

✦ Synopsis

The volumetric oxygen transfer coefficient, KLa, is one of the most important parameters in the scaleup of aerobic fermentation processes. It is a measure of the gas-liquidoxygen transfer performance of a given fermentor. Because of the involvement of oxygen in the metabolic energy supply, the KLa value may play a key role in the synthesis of products and biomass.

Methods for measuring K,a in fermentation processes may be divided into two types: the dynamic method and the steady-state method. The steady-state method makes use of the global balance of oxygen in the gas phase of the reactor. Some appreciable errors could occur due to the very small difference of oxygen concentrations between the entrance and the exit of the reactor. The gas balance method used commonly in culture conditions requires correction for temperature, pressure, and humidity.

The dynamic method to determine KLa attracts much attention because only one membrane-covered-electrode is needed for oxygen transfer studies. However, the method is subject to large errors if the dynamic response of the electrode is not considered. Since this method was proposed by Bandyopadhyay and co-workers' in 1967, many works2-* have been done from various aspects to improve the reliability of the method. Linek6 derived a general model describing the transient behavior of an oxygen probe based on more general assumptions than those considered previously. Koizumi and Aiba7 presented a reassessment of the dynamic KLa method by means of transfer function.

This report intends to present a quick, convenient, and reliable method for determination of KLu values in fermentation processes without difficulties encountered in the previous methods. In the previous communication ,* some preliminary considerations were discussed. Both theoretical considerations and experimental results in detail has been provided here.