Etude expérimentale et optimisation de la production d'un biopesticide bactérien en bioréacteur

Abstract

Biological control is considered a means of controlling the numerical density of pests, through the use of parasites, predators and pathogens, in addition to entomopathogens, which are microorganisms present in agricultural environments, which include bacteria, fungi and viruses. Bacillus subtilis, an aerobic bacterium capable of producing effective substances to combat the enemies of agricultural crops, by secreting a toxin called fengycin. The production of biopesticide, on a laboratory scale, in a 2 liter bioreactor, containing a culture medium based on olive pomace (a by-product of the olive industry) requires an optimization of the oxygen transfer in this place. The optimal kLa value was estimated at 0.0053 s-1 for values: Qa = 2 vvm, N = 300 rpm, S = 0.1%. The aeration rate and the agitation speed positively influence the oxygen transfer, while the substrate concentration has a negative and insignificant effect on the O2 transfer phenomenon. Olive pomace powder supplemented with peptone is sufficient for the multiplication of Bacillus sp. in a 2 liter bioreactor, and allows the production of fengycin, to fight against Fusarium F.O