Biosurfactants are molecules with surfactant properties produced by microorganisms, and can be used in various industrial sectors, e.g., the oil industry. These molecules can be used in enhanced oil recovery (EOR) in the pre-salt and post-salt reservoirs, where conditions of temperature, pressure, and salinity are quite varied, requiring a study of the stability of these molecules under these conditions. Bacillus velezensis H2O-1 produces five different surfactin homologs with a fatty-acid chain ranging from C11 to C16 and with a high capacity to reduce surface (24.8 mN.m⁻¹) and interfacial tensions (1.5 and 0.8 8 mN.m⁻¹ using light, medium oil and n-hexadecane, respectively). The critical micellar concentration (CMC) was 38.7 mg.L⁻¹. Inversion wettability tests were carried out under the salinity conditions found in the post-salt (35 g.L⁻¹) and pre-salt (70 g.L⁻¹) reservoirs, in which it was observed that the surfactin reversed 100 % of the wettability of the calcite impregnated with light and medium oil. Using a central composite rotatable design, we demonstrated that surfactin maintained its interfacial properties when subjected simultaneously to extreme conditions of pressure, temperature and salinity commonly found in the post-salt (70 °C, 70 g.L⁻¹ and 27.58 MPa) and pre-salt (100 °C, 150 g.L⁻¹ and 48.2 MPa) layers. The results presented here highlight the efficiency and stability of H2O-1 surfactin in environmental conditions found in pre-salt and post-salt oil reservoirs.

生物表面活性剂是由微生物产生的具有表面活性剂特性的分子，可用于各种工业部门，例如石油工业。这些分子可用于盐前和盐后油藏中的提高采油率 (EOR)，这些油藏的温度、压力和盐度条件变化很大，需要研究这些分子在这些条件下的稳定性。Bacillus velezensis H2O-1 产生五种不同的表面活性素同系物，其脂肪酸链范围从 C11 到 C16，并具有降低表面（24.8 mN.m ^-1）和界面张力（1.5 和 0.8 8 mN.m ^-1）的高能力分别使用轻油、中油和正十六烷）。临界胶束浓度 (CMC) 为 38.7 mg.L ^-1. 在盐后 (35 gL ^-1 ) 和盐前 (70 gL ^-1 ) 储层中发现的盐度条件下进行了反转润湿性测试，其中观察到表面活性素逆转了 100% 的润湿性方解石浸有轻油和中油。使用中心复合材料可旋转设计，我们证明了表面活性素在同时经受盐后（70°C，70 gL ^-1和 27.58 MPa）和盐前常见的极端压力、温度和盐度条件时保持其界面特性。盐 (100 °C, 150 gL ^-1和 48.2 MPa) 层。这里展示的结果突出了 H2O-1 表面活性素在盐前和盐后油藏中发现的环境条件下的效率和稳定性。