Importance of spore mutants for fed-batch and continuous fermentation ofBacillus subtilis

1995 ◽  
Vol 47 (6) ◽  
pp. 696-702 ◽  
Author(s):  
M. K. Oh ◽  
B. G. Kim ◽  
S. H. Park
1998 ◽  
Vol 75 (2-3) ◽  
pp. 235-248 ◽  
Author(s):  
Montserrat Sarrà ◽  
Josep A. Pérez-Pons ◽  
Francesc Gòdia ◽  
Carlos Casas Alvero

1993 ◽  
Vol 39 (4-5) ◽  
pp. 433-437 ◽  
Author(s):  
Traugott C. Sch�z ◽  
Hans-Peter Fiedler ◽  
Hans Z�hner

2005 ◽  
Vol 92 (3) ◽  
pp. 277-298 ◽  
Author(s):  
Britta Jürgen ◽  
Steffen Tobisch ◽  
Mogens Wümpelmann ◽  
Dirk Gördes ◽  
Andreas Koch ◽  
...  

2021 ◽  
Vol 11 (5) ◽  
pp. 12633-12641

High cell density fed-batch fermentation is the main strategy for recombinant hepatitis B surface antigen (rHBsAg) production. In this study, we employed short-term continuous fermentation to optimize the cell density of recombinant Pichia pastoris (P. pastoris). After reaching the maximum specified broth volume of 5 L in the fed-batch fermentation process, the operation mode was altered into the continuous mode with a dilution rate of 0.009 1/h. We used various values of methanol inflow to examine its impact as a limiting nutrient on cell density. After reaching the steady-state point, the continuous fermentation was stopped. The process's performance was evaluated based on titer, yield, productivity, and ease of process control. According to the results, the optimal methanol inflow in the pilot-scale fermentation process was 39.9 ml/h as the cell density increased from 363 g/l wet cell weight (WCW) in the fed-batch stage to 450 g/l WCW. We could successfully scale up the fermentation process with the biomass concentration of 450 g/l without having any major issues such as excessive heat dissipation or insufficient oxygen supply. This approach is a simple method for enhancing rHBsAg production efficiency in P. pastoris without requiring any new and complex facility.


Author(s):  
Martin Koller

Polyhydroxyalkanoates (PHA) are microbial biopolyesters utilized as “green plastics”. Their production under controlled conditions resorts to bioreactors operated in different modes. Because PHA biosynthesis constitutes a multiphase process, both feeding strategy and bioreactor operation mode need smart adaptation. Traditional PHA production setups based on batch, repeated batch, fed-batch or cyclic fed-batch processes are often limited in productivity, or display insufficient controllability of polyester composition. For highly diluted substrate streams like it is the case for (agro)industrial waste streams, fed-batch enhanced by cell recycling were recently reported as a viable tool to increase volumetric productivity. As emerging trend, continuous fermentation processes in single-, two-, and multi-stage setups are reported, which bring the kinetics of both microbial growth and PHA accumulation into agreement with process engineering, and allow tailoring PHA´s molecular structure. Moreover, we currently witness an increasing number of CO2-based PHA production processes using cyanobacteria; these light-driven processes resort to photobioreactors similar to those used for microalgae cultivation, and can be operated both discontinuously and continuously. This development goes in parallel to the emerging use of methane and syngas as an abundantly available gaseous substrates, which also calls for bioreactor systems with optimized gas transfer. The review sheds light on the challenges of diverse PHA production processes in different bioreactor types and operational regimes using miscellaneous microbial production strains such as extremophilic Archaea, chemoheterotrophic eubacteria and phototrophic cyanobacteria. Particular emphasize is dedicated to the limitations and promises of different bioreactor-strain combinations, and to efforts devoted to upscaling these processes to industrially relevant scales.


Sign in / Sign up

Export Citation Format

Share Document