Batch and fed-batch fermentation of Bacillus thuringiensis using starch industry wastewater as fermentation substrate.
Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch fermentation with two intermittent feeds (at 10 and 20 h) during the fermentation of 72 h gave the maximum delta-endotoxin concentration (1,672.6 mg/L) and entomotoxicity (Tx) (18.5 x 10(6) SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0 mg/L) and Tx (15.8 x 10(6) SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34 h) of the fermentation resulted in the formation of asporogenous variant (Spo-) from 36 h to the end of fermentation (72 h) which resulted in a significant decrease in spore and delta-endotoxin concentration and finally the Tx value. Tx of suspended pellets (27.4 x 10(6) SBU/mL) obtained in fed-batch fermentation with two feeds was the highest value as compared to other cases.
Vu
Khanh Dang
KD
INRS-ETE, Université du Québec, 490 rue de la Courrone, G1K 9A9, Québec, Canada.
Tyagi
Rajeshwar Dayal
RD
Valéro
José R
JR
Surampalli
Rao Y
RY
D000818:Animals; D001413:Bacillus thuringiensis / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis; D001427:Bacterial Toxins / Q000096:biosynthesis*; D005285:Fermentation; D007218:Industrial Microbiology / Q000379:methods*; D007220:Industrial Waste; D007313:Insecta; D007814:Larva; D013171:Spores, Bacterial / Q000254:growth & development*; D013213:Starch / Q000378:metabolism; D014865:Waste Disposal, Fluid
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D007220:Industrial Waste; D013213:Starch