脂肽类生物表面活性剂的最适水解条件

The Optimum Condition for Hydrolysis of Lipopeptide Biosurfactants

脂肽是一类由脂肪酸和肽环组成的生物表面活性剂,水解反应是其结构鉴定的关键步骤之一。传统的脂肽酸水解大多是在110℃下进行的。本文研究了水解反应条件对水解物中脂肪酸组成的影响,用GC-MS方法检测水解物中脱水产生的不饱和脂肪酸,确定了最适水解条件,即90℃条件下6 mol/L盐酸溶液中反应24 h。在该条件下脂肽水解反应完全,羟基脂肪酸和脂肪酸总量均达到最大;羟基脂肪酸脱水率较低,有利于脂肽中脂肪酸的结构解析。在水的沸点温度以下进行水解,无需压力容器,操作更方便安全。该方法可应用于蛋白类物质的水解反应。

Lipopeptide is a kind of biosurfactant which consists of a fatty acid chain and a cycle peptide. The hydrolysis of lipopeptides is an important step for their structure analysis. In the traditional acidic hydrolysis, the reaction was usually conducted at 110℃. In this paper, the influence of hydrolysis condition on the composition of fatty acids was investigated via GC-MS. The unsaturated fatty acids dehydrated from the β-hydroxy fatty acids were identified. Using the total amount of fatty acids, the amount of β-hydroxy fatty acids and the unsaturated fatty acids as indexes, an optimum hydrolysis condition for microbial lipopeptides was in 6 mol/L HCl solution at 90 ℃ for 24 h. Under mentioned condition, the lipopeptide was hydrolyzed completely, the amount of β-hydroxy fatty acids and the total amount of fatty acids reached maximums; at the same time, a very small amount of unsaturated fatty acids was induced, which could well meet the requirement of the structural determination of lipopeptide. And the hydrolysis carried out at the temperature below the water boiling point meant the reaction could be conducted in a non-pressure vessel, and was more convenient and safe to experimental operations. This approach can be applied for the hydrolysis of protein.