Switching industrial production processes from complex to defined media: method development and case study using the example of Penicillium chrysogenum

Abstract

BackgroundFilamentous fungi are versatile cell factories and widely used for the production of antibiotics, organic acids, enzymes and other industrially relevant compounds at large scale. As a fact, industrial production processes employing filamentous fungi are commonly based on complex raw materials. However, considerable lot-to-lot variability of complex media ingredients not only demands for exhaustive incoming components inspection and quality control, but unavoidably affects process stability and performance. Thus, switching bioprocesses from complex to defined media is highly desirable.ResultsThis study presents a strategy for strain characterization of filamentous fungi on partly complex media using redundant mass balancing techniques. Applying the suggested method, interdependencies between specific biomass and side-product formation rates, production of fructooligosaccharides, specific complex media component uptake rates and fungal strains were revealed. A 2-fold increase of the overall penicillin space time yield and a 3-fold increase in the maximum specific penicillin formation rate were reached in defined media compared to complex media.ConclusionsThe newly developed methodology enabled fast characterization of two different industrial Penicillium chrysogenum candidate strains on complex media based on specific complex media component uptake kinetics and identification of the most promising strain for switching the process from complex to defined conditions. Characterization at different complex/defined media ratios using only a limited number of analytical methods allowed maximizing the overall industrial objectives of increasing both, method throughput and the generation of scientific process understanding.

The development of an industrial-scale fed-batch fermentation simulation

“…2. Deviations in the raw material composition of these materials is expected for industrial fermentations (Posch et al, 2012). However there were no measurements of these raw M a n u s c r i p t materials available and hence these assumed deviations could not be validated.…”

Physiological description of multivariate interdependencies between process parameters, morphology and physiology during fed‐batch penicillin production

“…every 12–24 h. Based on these measurements, results from rate‐based physiological and morphological bioprocess analysis were calculated for every 12 h throughout the process duration of 180 h and used for further bioprocess analysis and modeling. For detailed discussion on calculation and verification of specific physiological rates and yields, the reader is referred to recent contributions . The general formula for specific rate calculation at the time for component i is illustrated in Eq.…”

“…For detailed discussion on calculation and verification of specific physiological rates and yields, the reader is referred to recent contributions. 30,40 The general formula for specific rate calculation at the time t n 1Dt=2 for component i is illustrated in Eq. 1, whereas yields are calculated as the ratio of two specific rates as shown in Eq.…”

“…In order to meet these economic requirements it is necessary to understand and control the biological system employed. 28 In this context, recently published statistically verified process characterization of morphology 29 and physiology 30 represent valuable approaches for fast process characterization. Systematic resolution of interrelations between inputs and outputs via design of experiments (DoE) accelerates bioprocess characterization and knowledge development and has been reviewed recently.…”

Computing the various pathways of penicillin synthesis and their molar yields

“…The bacteriostatic effect of Penicillium species was discovered by Alexander Fleming in 1928. Various Penicillium strains have been improved by genetic manipulation to increase the rate and yield of penicillin production (Christensen et al, 1995;Harris et al, 2007;Posch et al, 2012). They inhibit cell wall synthesis in many bacteria.…”