Escalado de procesos fermentativos aerobios en biorreactores tipo tanque agitado : Escalado de la producción de proteínas cristalinas con potencial insecticida a partir de aguas residuales con Bacillus thuringiensis sp. Kurstaki.

Abstract

This paper presents the theoretical scale-up production of the crystalline proteins whit insecticidal potential using starch industry wastewater since used Bacillus thuringiensis sp. Kurstaki, from a 15L bioreactor towards two larger scales of 50 and 150 L, by applying two scale-up protocols based on the volumetric mass transfer coefficient (kLa) and the dissolved oxygen (DO). Firstly, the operating parameters was defined for fermentative process in the prototype scale, such as: substrate, pH, temperature, aeration, stirring rate, type of bioreactor and productivity. Then, the bioreactors of the two laboratory model and pilot scales were dimensioned from geometric similarity relationships verified in the prototype. Subsequently, the most relevant scale-up criteria for the fermentation process were identified and estimated, where from as of these values the scale-up protocols were developed to define the operating conditions in the 50 and 150 L scales. It was established that in a bioreactor STR of 15L, defined as the prototype scale, operating at 350rpm, with 2.5 L/min of air and 30°C, it is feasible to produce a bioinsecticide with a concentration of 1043 (mg/l) of δ-endotoxins. It was estimated that the values of (kLa) and DO are 33.96 h-1 and 92%, respectively, which, when kept constant in the model scales, would ensure the same level of productivity when operating at 198 or 207 rpm and 1 vvm in the 50 scale. L; and 178 or 185 rpm and 1 vvm for the 150 L pilot scale.