Strain and process engineering toward continuous industrial fermentation

Abstract

Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

Key challenges in the advancement and industrialization of biobased and biodegradable plastics: a value chain overarching perspective

“… • Increase of bioprocess productivity towards the chemical industry’s performance metrics (i.e . , 100 g/l/h ( Lange, 2021 )) by advancing and scaling continuous fermentation, for example, which also affords tailored, high quality PHAs as compared to fed-batch processes ( Zinn et al, 2004 ; Hanik et al, 2019 ; Dong et al, 2023 ). Realizing high cell density of 100 g/l in continuous fermentation, which is half of what has been reported for fed-batch ( Arikawa et al, 2018 ), together with a growth rate of 0.5 h -1 and 80% PHA content, for example, would yield a >20 fold higher productivity (of 40 g/l/h) compared to the state-of-the-art in continuous PHA production ( Koller, 2018 ).…”