Department of Biotechnology Engineering, NMAM Institute of Technology-Affiliated to NITTE (Deemed to Be University), Nitte, Karnataka, 574110, India.
Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
Braz J Microbiol. 2022 Dec;53(4):2015-2025. doi: 10.1007/s42770-022-00811-4. Epub 2022 Sep 2.
Bacillus sp. WD22, previously isolated from refinery effluent, degraded 71% of C8 hydrocarbons present in 1.0% v/v PCO in seawater (control medium), which reduced to 16.3%, on addition of yeast extract. The bacteria produced a biosurfactant in both media, whose surface was observed to be amorphous in nature under FESEM-EDAX analysis. The biosurfactant was characterized as a linear surfactin by LCMS and FT-IR analysis. The critical micelle concentration was observed as 50 mg/L and 60 mg/L at which the surface tension of water was reduced to 30 mN/m. Purified biosurfactant could emulsify petroleum-based oils and vegetable oils effectively and was stable at all tested conditions of pH, salinity and temperature up to 80 °C. The biosurfactant production was found to be mixed growth associated in control medium, while it was strictly growth associated in medium with yeast extract as studied by the Leudeking-Piret model.
从炼油厂废水分离出的一株芽孢杆菌 WD22，在海水中（对照培养基），1.0%v/v PCO 中可降解 71%的 C8 烃，而添加酵母提取物后，C8 烃降解率降为 16.3%。在两种培养基中，该细菌均能产生生物表面活性剂，FESEM-EDAX 分析显示其表面呈无定形。通过 LCMS 和 FT-IR 分析，该生物表面活性剂被鉴定为线性表面活性剂。临界胶束浓度为 50mg/L 和 60mg/L，此时水的表面张力降至 30mN/m。纯化的生物表面活性剂可有效乳化石油基油和植物油，在所有测试的 pH 值、盐度和温度条件下（高达 80°C）均稳定。通过 Leudeking-Piret 模型研究发现，对照培养基中生物表面活性剂的产生与混合生长相关，而在含酵母提取物的培养基中则与严格的生长相关。
