Bio-interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India.
Bioresour Technol. 2020 Jul;307:123261. doi: 10.1016/j.biortech.2020.123261. Epub 2020 Mar 27.
This study aims to unveil the effect of biosurfactant as stimulant in crude oil bioremediation. Isolated oil-degrading strain, B. subtilis RSL 2 was optimized for the maximum oil degradation and biosurfactant production using Response surface methodology. The produced biosurfactant was characterized and investigated for its effect on microbial oil degradation in two modes (a) sequential and (b) simultaneous. The strain produced 3.5 g/L of biosurfactant at pH 4.0, 25 °C, using 1 g/L crude oil as the only C-source in 7 days, which was characterized as lipopeptide with a critical micelle concentration (CMC) of 0.5 g/L. The biosurfactant improved surface wettability of a hydrophobic substrate i.e. increased surface energy from 30 ± 1 to 35 ± 1 mJ/m. Further, the simultaneous feed of biosurfactant at 0.5 CMC enhanced oil biodegradation (72%) and biosurfactant production (5.2 g/L) by about 1.6 times than the sequential mode due to improvement in mobilization of oil thus making it more bioavailable.
本研究旨在揭示生物表面活性剂作为刺激物在原油生物修复中的作用。采用响应面法对分离的石油降解菌株枯草芽孢杆菌 RSL 2 进行了优化，以实现最大的石油降解和生物表面活性剂产量。对所产生的生物表面活性剂进行了表征，并研究了其在两种模式（a）顺序和（b）同时作用下对微生物油降解的影响。该菌株在 pH 4.0、25°C 下，以 1 g/L 的原油为唯一碳源，7 天内产生了 3.5 g/L 的生物表面活性剂，其特征为具有临界胶束浓度 (CMC) 为 0.5 g/L 的脂肽。生物表面活性剂提高了疏水性基质的润湿性，即表面能从 30±1 增加到 35±1 mJ/m。此外，由于油的可移动性提高，使油生物降解（72%）和生物表面活性剂生产（5.2 g/L）比顺序模式提高了约 1.6 倍，同时在 0.5 CMC 下添加生物表面活性剂，使其更具生物利用性。
