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Studies on Bacillus thuringiensis H-14 strains isolated in egypt-IV. characterization of fermentation conditions for
A Abdel-Hameed1, G Carlberg, O M El-Tayeb
1Department of Microbiology, Faculty of Pharmacy, Cairo University, Kasr-El-Aini Street, Cairo, Egypt.
Abstract:
Fermentation media formulated from inexpensive locally available ingredients, namely soya meal, Proflo (a partially defatted cooked cottonseed fiour) and molasses, were assessed for growth, sporulation and δ-endotoxin production, by a mosquito-toxic strain of Bacillus thuringlensis H-14 locally isolated in Egypt, using an 8 I working volume fermenter. The insecticidal activity was assayed against Culex piplens. Good growth and sporulation were obtained with all the tested medium combinations, but a medium composed of 3% (w/v) soya meal and 1% (w/v) molasses was the best for δ-endotoxin production. The optimal batch cultivation conditions with respect to aeration (0.37 to 0.62 vol/vol min(-1)), agitation (200 rev/min), pH (6.5 to 7.5), temperature (30°C) and initial concentration of carbon (1% w/v) and nitrogen (3% w/v) sources are also presented. This investigation shows that these locally available ingredients could be used for the production of low-priced mosquito larvicide in Egypt and other developing countries where these ingredients are avallable.
Insights
Researchers developed a low-cost mosquito larvicide using local ingredients like soya meal and molasses. This Bacillus thuringiensis H-14 based product shows promise for controlling Culex pipiens in developing countries.
Area of Science:
- Biotechnology
- Microbial Pest Control
- Industrial Microbiology
Background:
- Mosquito-borne diseases pose a significant public health challenge globally.
- Bacillus thuringiensis H-14 is a potent biological agent for mosquito larvae control.
- Developing cost-effective production methods for biopesticides is crucial for widespread adoption.
Purpose of the Study:
- To evaluate locally available ingredients for Bacillus thuringiensis H-14 fermentation.
- To optimize fermentation conditions for enhanced δ-endotoxin production.
- To assess the potential for producing an affordable mosquito larvicide.
Main Methods:
- Fermentation of Bacillus thuringiensis H-14 using soya meal, Proflo, and molasses in an 8L fermenter.
- Assessing bacterial growth, sporulation, and δ-endotoxin yield.
- Optimizing parameters including aeration, agitation, pH, temperature, and nutrient concentrations.
- Bioassay against Culex pipiens larvae.
Main Results:
- All tested media supported good growth and sporulation.
- A medium of 3% soya meal and 1% molasses yielded the highest δ-endotoxin production.
- Optimal conditions for fermentation were identified for aeration, agitation, pH, temperature, and nutrient levels.
- The produced larvicide demonstrated insecticidal activity against Culex pipiens.
Conclusions:
- Inexpensive, locally sourced ingredients can be effectively utilized for Bacillus thuringiensis H-14 cultivation.
- Optimized fermentation processes can lead to high yields of mosquito larvicide.
- This approach offers a sustainable and affordable solution for mosquito control in Egypt and other developing nations.
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