Division of Environmental Science & Ecological Engineering, College of Life Science & Biotechnology, Korea University, Seoul, Korea.
Water Environ Res. 2019 Aug;91(8):739-747. doi: 10.1002/wer.1103. Epub 2019 Apr 18.
The rhamnolipid biosurfactant-producing bacterium, strain SDRB-G7, was isolated from the sediment of Sindu-ri beach and identified as Rhodococcus fascians based on a phylogenetic analysis. Optimal activity, with the highest yield (2.441 g/L) and surface tension-reducing activity (24.38 mN/m), was observed when the cells were grown on olive oil as their sole source of carbon at pH 8.0. The rhamnolipid biosurfactant showed environmental stability at a variety of NaCl concentrations (2-20%) and pH values (2-12) even under acidic conditions. Of the initial anthracene, 66% was solubilized by 100% crude biosurfactant. Furthermore, 100% crude biosurfactant desorbed 81% of the anthracene in sediment into the aqueous phase. These results suggest that the rhamnolipid biosurfactant produced from R. fascians SDRB-G7 is a promising candidate for polycyclic aromatic hydrocarbon (PAH) removal from the sediment and can be an effective agent for processes that bioremediate PAHs such as surfactant-enhanced remediation. PRACTITIONER POINTS: Biosurfactants can accelerate desorption of PAHs and improve their solubility. BS-producing R. fascians SDRB-G7 was selected by screening of biochemical tests. Solubility of anthracene was enhanced by rhamnolipid produced by strain SDRB-G7. Microbial surfactant is a promising alternative for bioremediation of PAH-polluted sites.
从 Sindu-ri 海滩的沉积物中分离出了一种产生鼠李糖脂生物表面活性剂的细菌，菌株 SDRB-G7，并根据系统发育分析将其鉴定为节杆菌属 fascians。当细胞以橄榄油为唯一碳源在 pH 8.0 下生长时，观察到最佳活性，最高产量（2.441 g/L）和表面张力降低活性（24.38 mN/m）。鼠李糖脂生物表面活性剂在各种 NaCl 浓度（2-20%）和 pH 值（2-12）下表现出环境稳定性，即使在酸性条件下也是如此。初始蒽的 66%被 100%粗生物表面活性剂溶解。此外，100%粗生物表面活性剂将 81%的蒽从沉积物中解吸到水相中。这些结果表明，从 R. fascians SDRB-G7 产生的鼠李糖脂生物表面活性剂是一种从沉积物中去除多环芳烃（PAH）的有前途的候选物，并且可以作为增强修复等修复 PAHs 的有效剂。从业者要点：生物表面活性剂可以加速 PAHs 的解吸并提高其溶解度。通过生化试验筛选出产生生物表面活性剂的 R. fascians SDRB-G7。由 SDRB-G7 菌株产生的鼠李糖脂增强了蒽的溶解度。微生物表面活性剂是修复 PAH 污染场地的有前途的替代物。
