Abstract

The present study evaluated the surfactin production by Bacillus subtilis UFPEDA 438 using sugarcane molasses as a substrate. The effects of the cultivation conditions (temperature, agitation and aeration ratio) on the biosurfactant production and kinetic parameters were investigated. Characteristics of the biosurfactant were obtained after analyses of the emulsification index (EI) and critical micellar concentration (CMC) of the fermentation broth. The results showed that in relation to the product its formation kinetics is strongly affected by operational conditions. It was also observed that surfactin production can be partially dependent or fully independent on microbial growth. The maximum values of surfactin concentration (199.45 ± 0.13 mg/L) and productivity (8,187 mg/L.h) were obtained in the culture under cultivation time of 24 h, temperature of 36 °C, agitation of 100 rpm and aeration ratio of 0.4. Under optimal conditions, the fermentation broth achieved good emulsification capacity (EI >40%) and CMC value of 20.73 mg/L. The results revealed that Bacillus subtilis UFPEDA 438 is a good producer of biosurfactant and that sugarcane molasses is a viable substrate for the production of surfactin.

抽象的

本研究评估了枯草芽孢杆菌产生的表面活性素用甘蔗糖蜜作为底物的UFPEDA 438。研究了培养条件（温度，搅拌和通气比）对生物表面活性剂生产和动力学参数的影响。通过分析发酵液的乳化指数（EI）和临界胶束浓度（CMC），获得了生物表面活性剂的特性。结果表明，相对于产品，其形成动力学受到操作条件的强烈影响。还观察到，表面活性素的产生可以部分依赖或完全独立于微生物的生长。在24小时的培养时间，36°C的温度，100 rpm的搅拌和通气比为0.4的条件下，培养物中获得的表面活性素浓度（199.45±0.13 mg / L）和生产率（8,187 mg / Lh）的最大值。在最佳条件下，发酵液达到了良好的乳化能力（EI> 40％），CMC值为20.73 mg / L。结果显示枯草芽孢杆菌UFPEDA 438是生物表面活性剂的良好生产商，甘蔗糖蜜是生产表面活性素的可行底物。