Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), Alma Mater Studiorum-University of Bologna, Bologna, Italy.
Microb Cell Fact. 2017 Nov 2;16(1):186. doi: 10.1186/s12934-017-0797-3.
The application of chemical dispersants as a response to marine oil spills is raising concerns related to their potential toxicity also towards microbes involved in oil biodegradation. Hence, oil spills occurring under marine environments necessitate the application of biodispersants that are highly active, stable and effective under marine environment context. Biosurfactants from marine bacteria could be good candidates for the development of biodispersant formulations effective in marine environment. This study aimed at establishing a collection of marine bacteria able to produce surface-active compounds and evaluating the activity and stability of the produced compounds under conditions mimicking those found under marine environment context.
A total of 43 different isolates were obtained from harbor sediments. Twenty-six of them produced mainly bioemulsifiers when glucose was used as carbon source and 16 were biosurfactant/bioemulsifiers producers after growth in the presence of soybean oil. Sequencing of 16S rRNA gene classified most isolates into the genus Marinobacter. The produced emulsions were shown to be stable up to 30 months monitoring period, in the presence of 300 g/l NaCl, at 4 °C and after high temperature treatment (120 °C for 20 min). The partially purified compounds obtained after growth on soybean oil-based media exhibited low toxicity towards V. fischeri and high capability to disperse crude oil on synthetic marine water.
To the best of our knowledge, stability characterization of bioemulsifiers/biosurfactants from the non-pathogenic marine bacterium Marinobacter has not been previously reported. The produced compounds were shown to have potential for different applications including the environmental sector. Indeed, their high stability in the presence of high salt concentration and low temperature, conditions characterizing the marine environment, the capability to disperse crude oil and the low ecotoxicity makes them interesting for the development of biodispersants to be used in combatting marine oil spills.
作为应对海洋溢油的一种手段，化学分散剂的应用引起了人们对其潜在毒性的关注，这些毒性也可能对参与石油生物降解的微生物产生影响。因此，在海洋环境中发生的溢油事件需要应用在海洋环境背景下高度活跃、稳定和有效的生物分散剂。海洋细菌产生的生物表面活性剂可能是开发在海洋环境中有效的生物分散剂配方的良好候选物。本研究旨在建立能够产生表面活性化合物的海洋细菌集合体，并评估在模拟海洋环境条件下产生的化合物的活性和稳定性。
从港口沉积物中获得了总共 43 种不同的分离株。其中 26 种在以葡萄糖为碳源时主要产生生物乳化剂，而 16 种在存在大豆油的情况下则是生物表面活性剂/生物乳化剂的产生者。16S rRNA 基因测序将大多数分离株分类为海洋杆菌属。在 300g/L NaCl、4°C 和高温处理（120°C 20min）条件下，在长达 30 个月的监测期内，所产生的乳液保持稳定。在基于大豆油的培养基上生长后获得的部分纯化化合物对 V. fischeri 的毒性较低，并且对合成海水的原油具有高的分散能力。
据我们所知，以前没有报道过非致病性海洋细菌 Marinobacter 产生的生物乳化剂/生物表面活性剂的稳定性特征。所产生的化合物具有不同应用的潜力，包括环境领域。事实上，它们在高盐浓度和低温条件下的高稳定性，这些条件是海洋环境的特征，分散原油的能力和低生态毒性使它们成为开发用于海洋溢油处理的生物分散剂的有趣选择。
