Bacillus thuringiensis (Bt) is a widely used biopesticide. The bioinsecticide based on Bt is obtained by fermentation, but the substrates currently used for its production constitute ingredients of high commercial value. In this context, the use of agro-industrial residues as substrates is an alternative to make the fermentation process viable on a large scale, in addition to minimizing environmental problems and contributing to the destination of these residues for biotechnological purposes. In the first part of this study, a previously isolated spore forming soil bacteria (Bv5) harboring and expressing a novel cry 8A gene was confirmed as B. thuringiensis based on its morphological characteristics, Gram staining, scanning electron microscopy (SEM) and genome sequencing. Bv5 was established as a Gram-positive spore forming bacteria with ellipsoidal spores and small round toxins. Bv5 genome comprised of the 5.30 Mb chromosome and two megaplasmids of 450 kb and 261 kb, respectively, with cry 8A gene located on the smallest megaplasmid. In the second part of the study, the physiological profile of the Bv5 strain during fermentation in different agro-industrial biowastes (cassava wastewater, orange pulp wash and whey) was analyzed. The fermentation experiment was divided into two stages. In the first stage, the agro-industrial waste with or without salts with the best results for biomass, spores and proteins production was selected. In the second stage, the effect of the selected medium in original and diluted form with the C:N balance was evaluated, in two different fermentation times (72 h and 96 h). Pulp wash enriched with salts was selected as the most suitable medium for the growth of Bv5 strain in the first stage. In the second stage pulp wash (without dilution) with the addition of salts, and with nitrogen supplementation, was considered the best for cell growth, spore and toxin production by Bv5. To conclude, our study provide a new alternative for bio-waste from the orange juice industry, as well as potential culture medium for the Bt commercial scale production.

中文翻译：

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使用农业工业生物废物来生长和生产先前分离的苏云金芽孢杆菌菌株

苏云金芽孢杆菌（Bt）是一种广泛使用的生物农药。基于Bt的生物杀虫剂是通过发酵获得的，但目前用于其生产的底物构成了具有高商业价值的成分。在这种情况下，除了最大限度地减少环境问题并有助于将这些残留物用于生物技术目的之外，使用农业工业残留物作为底物是使发酵过程大规模可行的替代方案。在本研究的第一部分中，基于其形态特征、革兰氏染色、扫描电子显微镜（SEM）和基因组测序，先前分离的含有并表达新型cry 8A基因的孢子形成土壤细菌（Bv5）被确认为苏云金芽孢杆菌。Bv5 被确定为革兰氏阳性孢子形成细菌，具有椭圆形孢子和小圆形毒素。Bv5基因组由5.30 Mb染色体和两个分别为450 kb和261 kb的大质粒组成，其中cry 8A基因位于最小的大质粒上。在研究的第二部分中，分析了 Bv5 菌株在不同农工生物废物（木薯废水、橙浆洗涤液和乳清）中发酵过程中的生理特征。发酵实验分为两个阶段。在第一阶段，选择具有最佳生物质、孢子和蛋白质生产效果的含盐或不含盐的农工业废物。在第二阶段，在两个不同的发酵时间（72 小时和 96 小时）下评估原始和稀释形式的所选培养基对 C:N 平衡的影响。选择富含盐的纸浆洗涤液作为第一阶段最适合Bv5菌株生长的培养基。在第二阶段中，添加盐和补充氮的果肉洗涤（未稀释）被认为对于Bv5的细胞生长、孢子和毒素产生是最好的。总之，我们的研究为橙汁行业的生物废物提供了一种新的替代品，并为 Bt 商业规模生产提供了潜在的培养基。