Alternative low-cost process for large-scale production of Bacillus thuringiensis in a simple and novel culture system

ROJAS, NATALIA; E. LEWKOWICZ; NOBILE, MATIAS

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART B - PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2018 vol. 53 p. 719 - 728

0360-1234

An industrial-scale, profitable method for production of the most widely used bioinsecticide, Bacillus thuringiensis (Bt), is challenging because of its widespread application. The aim of this study is to present a strategy to develop a low-cost, large-scale bioprocess to produce BtH14.This studywas first focused on the design of a culture medium composed of economical and available components, such as glycerol and lysed Saccharomyces cerevisiae. The production goal of 1200 ITU was achieved using a medium composed of 20:20 g L-1of glycerol:lysedyeast in batch cultures. Efforts were subsequently focused on the design of an appropriate culture system, andan original two-stage culture system was proposed. First, yeast (the primary component of the culture medium) are cultivated using a minimal mineral medium and lysed, andin the second stage,Bt is cultivated in the same bioreactor using the lysed yeasts as culture medium (supplemented with a feeding pulse of 10 g L-1 glycerol). This system was called fedbatch one pot (FOP). A new inoculation strategy is also presented in this study, since these Bt cultures were inoculated directly with heat pre-treated spores instead of vegetative bacteria to facilitate the bioprocess. This study was developed from the laboratory to production-scale bioreactors (measuring from 500 mL to 2500 L), and the efficiency of the proposed strategy was evident in LD50 tests results, achieving 1796 ITU in large-scale processes. Both the use of non-conventional sources and the process development for biomass production are important for cost-effective production of Bt-based insecticides in mosquito control projects.