Efficient and cost-effective production of Bacillus thuringiensis subsp. aizawai spores and delta-endotoxins using agricultural raw materials and agro-industrial wastes under submerged fermentation

Abstract

In this study, cost-effective liquid culture media based on agricultural raw materials and agro-industrial wastes were developed for spores and delta-endotoxins production by a strain of B. thuringiensis subsp. aizawai used as a larvicide in wax moths control. The raw materials used include edible leguminous seeds, corn, wheat bran, dry palm date pulps, and corn forages. The agro-industrial wastes were dry palm dates pits and olive mill solid wastes. The protein and carbohydrate contents of the developed media were measured. Sporulation on the different developed media was monitored and delta-endotoxins produced were quantified. Mono-component media containing chickpea, red lentils, and wheat bran produced a spore count compared to the reference medium NYSM. The results showed that the dry palm date's pulp extract was the most efficient medium for spore production (1.43 × 1010 spores ml−1), and the chickpea medium was the most efficient for delta-endotoxins production.