Dhasayan Asha, Kiran G Seghal, Selvin Joseph
Department of Microbiology, Bharathidasan University, Tiruchirappalli, 620 024, India,
Appl Biochem Biotechnol. 2014 Dec;174(7):2571-84. doi: 10.1007/s12010-014-1209-3. Epub 2014 Oct 18.
Biosurfactant-producing Halomonas sp. MB-30 was isolated from a marine sponge Callyspongia diffusa, and its potency in crude oil recovery from sand pack column was investigated. The biosurfactant produced by the strain MB-30 reduced the surface tension to 30 mN m(-1) in both glucose and hydrocarbon-supplemented minimal media. The critical micelle concentration of biosurfactant obtained from glucose-based medium was at 0.25 mg ml(-1) at critical micelle dilution 1:10. The chemical structure of glycolipid biosurfactant was characterised by infrared spectroscopy and proton magnetic resonance spectroscopy. The emulsification activity of MB-30 biosurfactant was tested with different hydrocarbons, and 93.1 % emulsification activity was exhibited with crude oil followed by kerosene (86.6 %). The formed emulsion was stable for up to 1 month. To identify the effectiveness of biosurfactant for enhanced oil recovery in extreme environments, the interactive effect of pH, temperature and salinity on emulsion stability with crude oil and kerosene was evaluated. The stable emulsion was formed at and above pH 7, temperature >80 °C and NaCl concentration up to 10 % in response surface central composite orthogonal design model. The partially purified biosurfactant recovered 62 % of residual crude oil from sand pack column. Thus, the stable emulsifying biosurfactant produced by Halomonas sp. MB-30 could be used for in situ biosurfactant-mediated enhanced oil recovery process and hydrocarbon bioremediation in extreme environments.
从海洋海绵扩散佳丽海绵中分离出了产生物表面活性剂的嗜盐单胞菌属MB-30，并研究了其从砂柱中回收原油的能力。菌株MB-30产生的生物表面活性剂在添加葡萄糖和碳氢化合物的基本培养基中均可将表面张力降低至30 mN m(-1)。从基于葡萄糖的培养基中获得的生物表面活性剂在临界胶束稀释度为1:10时的临界胶束浓度为0.25 mg ml(-1)。通过红外光谱和质子磁共振光谱对糖脂生物表面活性剂的化学结构进行了表征。用不同的碳氢化合物测试了MB-30生物表面活性剂的乳化活性，原油的乳化活性为93.1%，其次是煤油（86.6%）。形成的乳液可稳定长达1个月。为了确定生物表面活性剂在极端环境中提高原油采收率的有效性，评估了pH值、温度和盐度对原油和煤油乳液稳定性的交互作用。在响应面中心复合正交设计模型中，在pH值为7及以上、温度>80°C和NaCl浓度高达10%的条件下形成了稳定的乳液。部分纯化的生物表面活性剂从砂柱中回收了62%的残余原油。因此，嗜盐单胞菌属MB-30产生的稳定乳化生物表面活性剂可用于原位生物表面活性剂介导的提高原油采收率过程以及极端环境中的碳氢化合物生物修复。
