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A procedure for high-yield spore production by Bacillus subtilis.
Sandra M Monteiro1, João J Clemente, Adriano O Henriques
1Instituto de Biologia Experimental e Tecnológica (IBET), Apartado 1, P-2781-901 Oeiras, Portugal.
Biotechnology Progress
|August 6, 2005
Summary
Optimizing Bacillus subtilis cultivation conditions significantly boosted vegetative cell and spore concentrations. A novel fed-batch bioprocess achieved a 19-fold increase in spore yield, surpassing previous records for Bacillus subtilis spore production.
Area of Science:
- Microbiology
- Biotechnology
- Industrial Microbiology
Background:
- Bacillus subtilis spores show promise as probiotics and for controlling zoonotic pathogens in animal agriculture.
- Optimizing growth and sporulation conditions is crucial for maximizing spore yields.
- Previous studies have explored batch cultivation, but fed-batch strategies offer potential for higher yields.
Purpose of the Study:
- To investigate the impact of cultivation conditions on Bacillus subtilis growth and sporulation.
- To develop an optimized fed-batch bioprocess for enhanced Bacillus subtilis spore production.
- To achieve significantly higher spore concentrations compared to existing methods.
Main Methods:
- Batch bioreactions at a 2-L scale were used to study the effects of pH, dissolved oxygen, and media composition.
- A fed-batch bioprocess was designed using exponential nutrient feeding profiles derived from mass balance equations.
- The feeding strategy was implemented during the exponential growth phase to maximize cell and spore yields.
Main Results:
- Optimized batch conditions increased maximum vegetative cell concentration to 2.2 x 10(10) cells/mL and spore concentration to 5.6 x 10(9) spores/mL.
- The developed fed-batch bioprocess further enhanced maximum vegetative cell concentration to 3.6 x 10(10) cells/mL and spore concentration to 7.4 x 10(9) spores/mL.
- The fed-batch process resulted in a 14-fold increase in vegetative cells and a 19-fold increase in spores, achieving a sporulation efficiency of 21%.
Conclusions:
- Cultivation condition optimization and fed-batch strategies are effective for significantly increasing Bacillus subtilis spore yields.
- The developed fed-batch bioprocess represents a substantial advancement in Bacillus subtilis spore production, yielding a 3-fold increase over the highest reported values.
- This optimized production method holds promise for the large-scale application of Bacillus subtilis spores in areas like probiotics and pathogen control.