Fed-batch fermentation studies with Bacillus thuringiensis H-14 synthesising endotoxin.
Cell yield and toxicity of B. thuringiensis H-14 was improved markedly by adopting a simple fed-batch fermentation technique based on controlling glucose concentration. Maintenance of steady glucose concentration (0.3-0.5%) in the culture medium was achieved by the continuous addition of concentrated glucose solution. Addition of glucose at 3 g/hr/l of culture starting from 3rd hr till 16th hr of fermentation was found to yield cell densities of 80 g/l (wet weight) which represented a nearly 3-fold increase over the batch mode. A fivefold increase in toxicity was obtained by fed-batch fermentation. Cultivation of B. thuringiensis H-14 to high cell densities had no negative effect on sporulation and toxin synthesis. The rate of pH drop and dissolved oxygen level were within manageable limits.
Kuppusamy
M
M
Vector Control Research Centre, Pondicherry, India.
Balaraman
K
K
D001413:Bacillus thuringiensis / Q000254:growth & development* / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins / Q000096:biosynthesis*; D005285:Fermentation; D006460:Hemolysin Proteins
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis