Biosurfactants (BS) and bioemulsifiers (BE) are amphiphilic molecules that are produced by a wide range of microorganisms. Although the chemical composition of BS and BE is different, both BS/BE have recognized emulsifying properties, which are the focus of this study. Herein, a rapid and simple analytical method to quantify the emulsifying activity (EA) of a product produced by the actinomycete Gordonia alkanivorans strain 1B (BS/BE), which exhibits emulsifying properties, was developed. The analytical approach was based on the ability of a BS/BE solution to form a stable emulsion when mixed with n-heptane. So, using 4 mL screw cap glass tubes (10 × 75 mm, ND10 caps with PTFE septum), the EA was assessed by adding 1 mL of n-heptane to 1 mL of an aqueous solution containing the test product, mix by vortexing at high speed (2 min) and place the tube in an upright stable position for 10 _min before analyzing. A set of emulsification tests with increasing volumes of test product solutions was carried out until 100% emulsion was obtained in the organic phase. One emulsification unit was defined as the minimum volume of product (Vol_min of emulsifier/surfactant, up to 1 mL) needed to form and maintain 100% emulsion in the organic phase. The corresponding emulsifying activity value is presented in U/mL, and it is calculated as: EA (product) = 1 U/Vol_min (mL). Further validation by testing several synthetic surfactants and industrial/domestic dishwashing detergents, in parallel with the bacterial crude BS/BE, towards emulsifying activity determination (U/mL) was performed demonstrating the wide range of the method applicability. Moreover, the specific emulsifying activity for each product tested was estimated though correlation analysis (linear regression) between volumetric emulsifying activity (U/mL) and product concentration (g/L). Indeed, this new analytical approach to quantify the emulsifying activity is accurate and reproducible, and consequently it can be a promising tool to apply in screening/monitorization studies on BS/BE production enabling reliable comparisons.

生物表面活性剂 (BS) 和生物乳化剂 (BE) 是由多种微生物产生的两亲性分子。尽管 BS 和 BE 的化学成分不同，但 BS/BE 都具有公认的乳化性能，这是本研究的重点。在此，一种快速且简单的分析方法来量化由放线菌Gordonia alkanivorans产生的产品的乳化活性 (EA)开发了具有乳化特性的菌株 1B (BS/BE)。分析方法基于 BS/BE 溶液与正庚烷混合时形成稳定乳液的能力。因此，使用 4 mL 螺旋盖玻璃管（10 × 75 mm，带有 PTFE 隔垫的 ND10 盖），通过将 1 mL 正庚烷添加到 1 mL 含有测试产品的水溶液中，通过涡旋混合在高速（2 分钟）并将试管置于直立稳定位置 10_分钟，然后再进行分析。进行一组乳化测试，增加测试产品溶液的体积，直到在有机相中获得 100% 的乳液。一个乳化单位定义为产品的最小体积（Vol _min乳化剂/表面活性剂，最多 1 mL) 需要在有机相中形成和保持 100% 乳液。相应的乳化活性值以 U/mL 表示，计算公式为：EA（产品）= 1 U/Vol _min（毫升）。通过测试几种合成表面活性剂和工业/家用餐具洗涤剂，与细菌粗 BS/BE 平行，对乳化活性测定 (U/mL) 进行了进一步验证，证明了该方法的广泛适用性。此外，通过体积乳化活性 (U/mL) 和产品浓度 (g/L) 之间的相关性分析（线性回归）估计每种测试产品的比乳化活性。事实上，这种量化乳化活性的新分析方法是准确且可重复的，因此它可以成为一种有前途的工具，可用于 BS/BE 生产的筛选/监测研究，从而实现可靠的比较。