Sultana Shahnaz, Sultana Rokaia, Al-Mansur Md Abdullah, Akbor Md Ahedul, Bhuiyan Nasrin Akter, Ahmed Shamim, Yasmin Sabina, Shofiul Islam Molla Jamal A H M
Institute of National Analytical Research and Services (INARS), Bangladesh Council of Scientific and Industrial Research (BCSIR) New Elephant Road Dhaka 1205 Bangladesh
School of Life and Environmental Sciences, University of Sydney Darlington NSW 2008 Australia
RSC Adv. 2024 Aug 5;14(34):24516-24533. doi: 10.1039/d4ra02572e.
Surfactants can reduce the interfacial surface tension between two immiscible liquids making them a desirable component for various industrial applications. However, the toxic nature of chemical surfactants brought immense attention towards biosurfactants. Being biodegradable, biosurfactants are eco-friendly and considered safer for different commercial uses. This study focused on the production of biosurfactant from an oil-degrading bacteria and its functional efficacy for prospective industrial applications. Here, a promising oil-tolerant strain, S2 was isolated from oil contaminated sites which showed >50% degradation of convoluted crude oil within 28 days in comparison to a control. The isolate was then found to produce an excellent surface-active compound with an emulsification index of 67.30 ± 0.8% and could reduce the surface tension up to 36.86 ± 0.36 mN m. It also manifested a critical micelle concentration of 45 mg L while reducing the surface tension from 72 to 30 mN m. When extracting biosurfactant from isolated bacteria, ethyl acetate extraction showed 1.5 times greater efficacy than chloroform : methanol extraction. The purified biosurfactant was characterized using TLC, H NMR, 13C NMR, FTIR, elemental analyses and spectrophotometric techniques leading to its identification as a rhamnolipid. The stability of produced biosurfactant at higher temperature (up to 180 °C) was determined by thermal analysis, endorsing its application in high temperature reservoir conditions. Additionally, the extracted biosurfactant showed excellent foaming efficacy with insignificant antibacterial and cytotoxic responses, which indicates their potential application in cleaning and cosmetics industries. Thus, the present study outlines a bi-functional novel isolate S2 which could play a significant role in oil remediation from the environment as well as serve as a potential source of non-toxic and eco-friendly biosurfactants for various industrial applications.
表面活性剂可以降低两种互不相溶液体之间的界面表面张力，使其成为各种工业应用中理想的成分。然而，化学表面活性剂的毒性引发了人们对生物表面活性剂的极大关注。生物表面活性剂具有生物可降解性，对环境友好，被认为在不同商业用途中更安全。本研究聚焦于从一种石油降解细菌生产生物表面活性剂及其在预期工业应用中的功能功效。在此，从受石油污染的场地分离出一株有前景的耐油菌株S2，与对照相比，该菌株在28天内对复杂原油的降解率>50%。然后发现该分离株能产生一种优良的表面活性化合物，乳化指数为67.30±0.8%，可将表面张力降低至36.86±0.36 mN/m。它还表现出临界胶束浓度为45 mg/L，同时将表面张力从72 mN/m降低至30 mN/m。从分离出的细菌中提取生物表面活性剂时，乙酸乙酯提取的效果比氯仿∶甲醇提取高1.5倍。使用薄层色谱法、氢核磁共振、碳-13核磁共振、傅里叶变换红外光谱、元素分析和分光光度技术对纯化的生物表面活性剂进行了表征，结果表明其为鼠李糖脂。通过热分析确定了所生产的生物表面活性剂在较高温度（高达180℃）下的稳定性，这支持了其在高温油藏条件下的应用。此外，提取的生物表面活性剂表现出优异的发泡功效，抗菌和细胞毒性反应不明显，这表明它们在清洁和化妆品行业具有潜在应用。因此，本研究概述了一种双功能新型分离株S2，它在从环境中修复石油方面可发挥重要作用，并可作为各种工业应用中无毒且环保的生物表面活性剂的潜在来源。
