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Significant decrease of broth viscosity and glucose consumption in erythromycin fermentation by dynamic regulation of
Yong Chen1, Zejian Wang, Ju Chu
1State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
Bioresource Technology
|March 19, 2013
Summary
Controlling nitrogen sources like ammonium sulfate in erythromycin fermentation reduces broth viscosity and glucose consumption. This strategy enhances erythromycin A production by optimizing nutrient regulation and metabolic pathways.
Area of Science:
- Biotechnology
- Industrial Microbiology
- Biochemical Engineering
Background:
- High broth viscosity and glucose consumption in erythromycin fermentation pose challenges to efficient production.
- Nitrogen sources significantly influence microbial metabolism and fermentation broth properties.
Purpose of the Study:
- To investigate the impact of nitrogen sources on broth viscosity and glucose consumption during erythromycin fermentation.
- To optimize erythromycin A production by controlling key fermentation parameters.
Main Methods:
- Controlled fermentation experiments manipulating ammonium sulfate, phosphate salt, and soybean meal concentrations.
- Monitoring of broth viscosity, glucose consumption, proteinase activity, and erythromycin A production.
- Analysis of metabolic byproducts (propionate, succinate) and precursor levels (methylmalonyl-CoA, propionyl-CoA).
Main Results:
- Adjusting ammonium sulfate concentration decreased broth viscosity by 18.2% and glucose consumption by 61.6%, with minimal impact on erythromycin biosynthesis.
- Rational regulation of phosphate salt, soybean meal, and ammonium sulfate increased erythromycin A production by 8.7% while maintaining low viscosity and glucose consumption.
- Ammonium sulfate controlled proteinase activity, linked to soybean meal utilization and cell growth; pellet formation reduced viscosity. Increased propionate and succinate accumulation suggested enhanced flux to erythromycin A.
Conclusions:
- Optimizing nitrogen sources, particularly ammonium sulfate, is crucial for managing broth viscosity and glucose consumption in erythromycin fermentation.
- A novel regulation strategy involving phosphate salt, soybean meal, and ammonium sulfate effectively enhances erythromycin A yield.
- Metabolic insights suggest that increased propionate and succinate levels, driven by propanol consumption, contribute to higher erythromycin A biosynthesis.
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