The search for novel biosurfactants (Bs) requires the isolation of microorganisms from different environments. The Gulf of Mexico (GoM) is a geographical area active in the exploration and exploitation of hydrocarbons. Recent metagenomic and microbiologic studies in this area suggested a potential richness for novel Bs microbial producers. In this work, nineteen bacterial consortia from the GoM were isolated at different depths of the water column and marine sediments. Bs production from four bacterial consortia was detected by the CTAB test and their capacity to reduce surface tension (ST), emulsion index (EI₂₄), and hemolytic activity. These bacterial consortia produced Bs in media supplemented with kerosene, diesel, or sucrose. Cultivable bacteria from these consortia were isolated and identified by bacterial polyphasic characterization. In some consortia, Enterobacter cloacae was the predominant specie. E. cloacae BAGM01 presented Bs activity in minimal medium and was selected to improve its Bs production using a Taguchi and Box-Behnken experimental design; this strain was able to grow and presented Bs activity at 35 g L⁻¹ of NaCl. This Bs decreased ST to around 34.5 ± 0.56 mNm⁻¹ and presented an EI₂₄ of 71 ± 1.27%. Other properties of this Bs were thermal stability, stability in alkaline conditions, and stability at high salinity, conferring important and desirable characteristics in multiple industries. The analysis of the genome of E. cloacae BAGM01 showed the presence of rhlAB genes that have been reported in the synthesis of rhamnolipids, and alkAB genes that are related to the degradation of alkanes. The bioactive molecule was identified as a rhamnolipid after HPLC derivatization, ¹H NMR, and UPLC-QTOF-MS analysis.

寻找新型生物表面活性剂 (Bs) 需要从不同环境中分离微生物。墨西哥湾 (GoM) 是一个活跃于油气勘探和开采的地理区域。该领域最近的宏基因组学和微生物学研究表明，新型 Bs 微生物生产者具有潜在的丰富性。在这项工作中，在不同深度的水柱和海洋沉积物中分离了来自 GoM 的 19 个细菌聚生体。通过 CTAB 测试检测了四种细菌聚生体的 Bs 产量及其降低表面张力 (ST)、乳液指数 (EI ₂₄) 和溶血活性。这些细菌聚生体在补充有煤油、柴油或蔗糖的培养基中产生 Bs。通过细菌多相特征分离和鉴定来自这些聚生体的可培养细菌。在一些联盟中，阴沟肠杆菌是主要物种。E. cloacae BAGM01 在基本培养基中表现出 Bs 活性，并被选择使用田口和 Box-Behnken 实验设计来提高其 Bs 产量；该菌株能够在 35 g L ^-1 NaCl 下生长并呈现 Bs 活性。该 Bs 将 ST 降低至约 34.5 ± 0.56 mNm ^-1并呈现 EI ₂₄71 ± 1.27%。这种 Bs 的其他特性是热稳定性、碱性条件下的稳定性和高盐度下的稳定性，赋予多个行业重要和理想的特性。E. cloacae BAGM01的基因组分析表明存在已报道的鼠李糖脂合成中的rhl AB 基因和与烷烃降解相关的alk AB 基因。经高效液相色谱衍生化、¹ H NMR 和 UPLC-QTOF-MS 分析后，生物活性分子被鉴定为鼠李糖脂。