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<p>Delta-endotoxins are produced by <i>Bacillus thuringiensis</i> (<i>Bt</i>) and have their main application in agriculture to manage insect crops and as antimicrobial. Its large scale production is limited by oxygen availability during <i>Bt</i> fermentation since delta-endotoxin synthesis requires high oxygen level. Therefore, it requires the enhancement of the agitation speed and air flow rate, which could be solved by adding an oxygen vector. So, the objective was to evaluate the use of oxygen vectors (soybean, corn and sunflower oil) on the enhancement of delta-endotoxin production and its toxicity against <i>Spodoptera frugiperda</i> and pathogenic microorganisms. In this way, the effects of oils on fermentation were studied from a 2<sup>4</sup> full experimental design, where their concentration varied from 0% to 3%. Posteriorly, the best oil and concentration to produce delta-endotoxin was studied in a 7.5&#xa0;L agitated tank bioreactor. The experimental design revealed that corn oil (3%) and sunflower oil (3%) could significantly enhance delta-endotoxin production, and this combination was considered the best condition to produce delta-endotoxins. In addition, kinetics parameters like <i>X</i><sub><i>m</i></sub>, <i>P</i><sub><i>x</i></sub>, <i>µ</i><sub><i>X.max</i></sub> and <i>µ</i><sub><i>S.max</i></sub> were increased in comparison to a fermentation without oxygen vector. Delta-endotoxins produced in the presence of oils showed higher activity against <i>S. frugiperda</i> and bacteria isolated from goat mastitis. Therefore, this research demonstrates that corn and sunflower oils can serve as oxygen vectors, enhancing both the production of delta-endotoxins and their toxicity against pathogenic bacteria and Lepidopterans.</p>

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Delta-endotoxin production and toxicity enhancement by using vegetable oils as oxygen vectors

  • 期刊论文

  • 发表日期：

    2025年12月24日

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  • Túlio Alexandre Freire da Silva,
  • Beatriz Rayana Damásio de Andrade,
  • Lívia Santos de Freitas,
  • Evelyn Geovanna Gomes Carvalho e Silva,
  • Emmily Vitoria Gomes da Silva,
  • Leandro Fragoso Lins,
  • José de Paula Oliveira,
  • Raquel Pedrosa Bezerra,
  • Ana Lúcia Figueiredo Porto

摘要

Delta-endotoxins are produced by Bacillus thuringiensis (Bt) and have their main application in agriculture to manage insect crops and as antimicrobial. Its large scale production is limited by oxygen availability during Bt fermentation since delta-endotoxin synthesis requires high oxygen level. Therefore, it requires the enhancement of the agitation speed and air flow rate, which could be solved by adding an oxygen vector. So, the objective was to evaluate the use of oxygen vectors (soybean, corn and sunflower oil) on the enhancement of delta-endotoxin production and its toxicity against Spodoptera frugiperda and pathogenic microorganisms. In this way, the effects of oils on fermentation were studied from a 24 full experimental design, where their concentration varied from 0% to 3%. Posteriorly, the best oil and concentration to produce delta-endotoxin was studied in a 7.5 L agitated tank bioreactor. The experimental design revealed that corn oil (3%) and sunflower oil (3%) could significantly enhance delta-endotoxin production, and this combination was considered the best condition to produce delta-endotoxins. In addition, kinetics parameters like Xm, Px, µX.max and µS.max were increased in comparison to a fermentation without oxygen vector. Delta-endotoxins produced in the presence of oils showed higher activity against S. frugiperda and bacteria isolated from goat mastitis. Therefore, this research demonstrates that corn and sunflower oils can serve as oxygen vectors, enhancing both the production of delta-endotoxins and their toxicity against pathogenic bacteria and Lepidopterans.