PDF(Pubmed)
Abstract：
BACKGROUND: Sophorolipids (SLs) are a class of natural, biodegradable surfactants that found their way as ingredients for environment friendly cleaning products, cosmetics and nanotechnological applications. Large-scale production relies on fermentations using the yeast Starmerella bombicola that naturally produces high titers of SLs from renewable resources. The resulting product is typically an extracellular mixture of acidic and lactonic congeners. Previously, we identified an esterase, termed Starmerella bombicola lactone esterase (SBLE), believed to act as an extracellular reverse lactonase to directly use acidic SLs as substrate.
RESULTS: We here show based on newly available pure substrates, HPLC and mass spectrometric analysis, that the actual substrates of SBLE are in fact bola SLs, revealing that SBLE actually catalyzes an intramolecular transesterification reaction. Bola SLs contain a second sophorose attached to the fatty acyl group that acts as a leaving group during lactonization.
CONCLUSIONS: The biosynthetic function by which the Starmerella bombicola \'lactone esterase\' converts acidic SLs into lactonic SLs should be revised to a \'transesterase\' where bola SL are the true intermediate. This insights paves the way for alternative engineering strategies to develop designer surfactants.
RESULTS: We here show based on newly available pure substrates, HPLC and mass spectrometric analysis, that the actual substrates of SBLE are in fact bola SLs, revealing that SBLE actually catalyzes an intramolecular transesterification reaction. Bola SLs contain a second sophorose attached to the fatty acyl group that acts as a leaving group during lactonization.
CONCLUSIONS: The biosynthetic function by which the Starmerella bombicola \'lactone esterase\' converts acidic SLs into lactonic SLs should be revised to a \'transesterase\' where bola SL are the true intermediate. This insights paves the way for alternative engineering strategies to develop designer surfactants.
摘要：
背景：槐糖脂（SL）是一类天然的，可生物降解的表面活性剂，成为环保清洁产品的成分，化妆品和纳米技术的应用。大规模生产依赖于使用酵母Starmerellabombicola的发酵，该酵母从可再生资源自然产生高滴度的SL。所得产物通常是酸性和内酯同源物的细胞外混合物。以前,我们发现了一种酯酶,称为Starmerellabombicola内酯酯酶（SBLE），被认为是直接使用酸性SL作为底物的细胞外反向内酯酶。
结果：我们在这里展示了基于新获得的纯底物，HPLC和质谱分析，SBLE的实际底物实际上是BolaSL，表明SBLE实际上催化分子内酯交换反应。BolaSL含有与脂肪酰基连接的第二槐糖，该脂肪酰基在内酯化过程中充当离去基团。
结论：Starmerellabombicola内酯酯酶将酸性SL转化为内酯SL的生物合成功能应修改为“转酯酶”，其中bolaSL是真正的中间体。这一见解为开发设计型表面活性剂的替代工程策略铺平了道路。
结果：我们在这里展示了基于新获得的纯底物，HPLC和质谱分析，SBLE的实际底物实际上是BolaSL，表明SBLE实际上催化分子内酯交换反应。BolaSL含有与脂肪酰基连接的第二槐糖，该脂肪酰基在内酯化过程中充当离去基团。
结论：Starmerellabombicola内酯酯酶将酸性SL转化为内酯SL的生物合成功能应修改为“转酯酶”，其中bolaSL是真正的中间体。这一见解为开发设计型表面活性剂的替代工程策略铺平了道路。
