Surfactin is one of the main lipopeptide biosurfactants produced by different species of Bacillus subtilis. This study aims to analyze the effect of starch‐coated Fe0 and Fe3+ nanoparticles on the biomass and biosurfactant production of Bacillus subtilis. Out of 70 soil samples, 20 Bacillus were isolated and genome sequenced by biochemical methods and 16S rRNA gene. Quantitative and qualitative screening methods were used to isolate and detect biosurfactant production. For the aim of this study, 61 and 63 (Bacillus subtilis subsp. Inaquosorum) were selected. Then, hemolytic activity, biomass amount, surfactant production, and reduction of surface tension in Minimal Salt Medium containing Fe0 and Fe3+ nanoparticles were examined after 48, 72, and 96 h of culture. Strain 61 was the best bacterium and Fe3+ was the best nanoparticle. The results were compared with the results of non‐nanoparticle bioreactor. The results showed the amount of biomass, surfactin, and surface tension decrease, 72 h after growth in 61 strain containing Fe3+ reached the highest values. Surfactin from strain 61 culture in the Fe3+nanoparticle bioreactor after 72 h of growth showed higher production than the same strain culture after 72 h without Fe3+, if continuing the research, this strain can be commercialized in the future.

中文翻译：

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生物反应器中的表面活性素生产：强调磁性纳米粒子的应用

Surfactin是由不同种类的枯草芽孢杆菌产生的主要脂肽生物表面活性剂之一。本研究旨在分析淀粉包覆的 Fe0 和 Fe3+ 纳米粒子对枯草芽孢杆菌生物量和生物表面活性剂生产的影响。在70份土壤样品中，通过生化方法和16S rRNA基因分离出20株芽孢杆菌并对其进行了基因组测序。定量和定性筛选方法用于分离和检测生物表面活性剂的产生。出于本研究的目的，选择了 61 和 63（枯草芽孢杆菌亚种 Inaquosorum）。然后，在培养 48、72 和 96 小时后，在含有 Fe0 和 Fe3+ 纳米颗粒的最低盐培养基中检测溶血活性、生物量、表面活性剂的产生和表面张力的降低。菌株 61 是最好的细菌，Fe3+ 是最好的纳米颗粒。将结果与非纳米颗粒生物反应器的结果进行比较。结果表明，61株含Fe3+的菌株在生长72h后生物量、表面活性素和表面张力均下降，达到最高值。在 Fe3+ 纳米颗粒生物反应器中培养 72 小时后，来自菌株 61 培养物的表面活性素比没有 Fe3+ 培养 72 小时后的相同菌株培养物的产量更高，如果继续研究，该菌株将来可以商业化。