On-line determination of acetic acid in a continuous production of Acetobacter aceticus

Bioprocess monitoring and computer control: key roots of the current PAT initiative

This review article has been written for the journal, Biotechnology and Bioengineering, to commemorate the 70th birthday of Daniel I.C. Wang, who served as doctoral thesis advisor to each of the co-authors, but a decade apart. Key roots of the current PAT initiative in bioprocess monitoring and control are described, focusing on the impact of Danny Wang's research as a professor at MIT. The history of computer control and monitoring in biochemical processing has been used to identify the areas that have already benefited and those that are most likely to benefit in the future from PAT applications. Past applications have included the use of indirect estimation methods for cell density, expansion of on-line/at-line and on-line/in situ measurement techniques, and development of models and expert systems for control and optimization. Future applications are likely to encompass additional novel measurement technologies, measurements for multi-scale and disposable bioreactors, real time batch release, and more efficient data utilization to achieve process validation and continuous improvement goals. Dan Wang's substantial contributions in this arena have been one key factor in steering the PAT initiative towards realistic and attainable industrial applications.

Progress in monitoring, modeling and control of bioprocesses during the last 20 years

The paper gives a review on the recent development of bioprocess engineering. It includes monitoring of product formation processes by flow injection analysis, various types of chromatographic and spectroscopic methods as well as by biosensors. The evaluation of mycelial morphology and physiology by digital image analysis is discussed also. It deals with advanced control of indirectly evaluated process variables by means of state estimation/observer, with the use of structured and hybrid models, expert systems and pattern recognition for process optimization and gives a short report on the state of the art of metabolic flux analysis and metabolic engineering.

Biosensors for food analysis

Concerning speed, cost and on-line capabilities, biosensors offer attractive alternatives to existing methods for food analysis. They make monitoring and control of manufacturing processes possible. Furthermore, portable biosensors could be used for monitoring in manufacturing, retail and distribution of foods. An overview is given about existing biosensors for foodstuffs that could find applications in food industry.

D- and L-lactate determination in dairy products: presentation of a fast automated analysis system

A flow-injection system is presented, which is versatile, automated and has an integrated enzyme system. Its efficiency at determining D- and L-lactate separately in dairy products is compared with the officially used reference method (DIN 10335). By means of a mathematical elimination of matrix effects, the pretreatment steps can be clearly reduced. As a result of the immobilization of the enzymes, an appropriate automation software and an adaptation of the system developed to the given medium, the analysis could be performed within 5 min and was distinctly cheaper than alternative methods. The values determined in 15 different dairy products deviated from those of the reference method by 3% at a maximum.