Optimal control of penicillin production, using a mini-computer

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.

Influence of medium composition on penicillin V production in a stirred tank reactor

Penicillin production with a high-producing strain Penicillium chrysogenum was investigated under well-controlled conditions in a stirred tank reactor with complex media containing lard oil and lactose on the one hand, and lactose on the other hand. With lard oil, cell growth and product formation rates were higher, and the production time was shorter by 40 h than without lard oil. On account of the longer production time without lard oil, the amount of beta-lactam compounds was higher (29.93 g l-1), but the mole fraction of the decomposed products (penicilloic acid and penilloic acid) was larger (0.282) than the amount of penicillin V (23.25 g l-1) and the decomposed mole fraction (0.0747) with lard oil. The final product concentrations were about the same (20.86 g l-1 or 35,462 IU ml-1 with lard oil, and 20.43 g l-1 or 34510 IU ml-1 without lard oil). The mole fractions of the by-product (p-OH-penicillin V) were 0.0365 and 0.066. The substitution of lard oil with lactose is possible without a considerable reduction of process performance.