Yakimov M M, Timmis K N, Wray V, Fredrickson H L
Technical University of Braunschweig, Germany.
Appl Environ Microbiol. 1995 May;61(5):1706-13. doi: 10.1128/aem.61.5.1706-1713.1995.
Strain BAS50, isolated from a petroleum reservoir at a depth of 1,500 m and identified as Bacillus licheniformis, grew and produced a lipopeptide surfactant when cultured on a variety of substrates at salinities of up to 13% NaCl. Surfactant production occurred both aerobically and anaerobically and was optimal at 5% NaCl and temperatures between 35 and 45 degrees C. The biosurfactant, termed lichenysin A, was purified and chemically characterized. A tentative structure and composition for the surfactant are described. Lichenysin A is a mixture of lipopeptides, with the major components ranging in size from 1,006 to 1,034 Da. The lipid moiety contains a mixture of 14 linear and branched beta-hydroxy fatty acids ranging in size from C12 to C17. There are seven amino acids per molecule. The peptide moiety is composed of the following amino acids: glutamic acid as the N-terminal amino acid, asparagine, valine, leucine, and isoleucine as the C-terminal amino acid, at a ratio of 1.1:1.1:1.0:2.8:1.0, respectively. Purified lichenysin A decreases the surface tension of water from 72 mN/m to 28 mN/m and achieves the critical micelle concentration with as little as 12 mg/liter, characterizing the product as a powerful surface-active agent that compares favorably to others surfactants. The antibacterial activity of lichenysin A has been demonstrated.
从1500米深处的石油储层中分离出的菌株BAS50，经鉴定为地衣芽孢杆菌，当在高达13%氯化钠盐度的多种底物上培养时，它能够生长并产生一种脂肽表面活性剂。表面活性剂的产生在需氧和厌氧条件下均会发生，在5%氯化钠以及35至45摄氏度的温度下产量最佳。这种被称为地衣溶素A的生物表面活性剂经过了纯化和化学表征。文中描述了该表面活性剂的初步结构和组成。地衣溶素A是一种脂肽混合物，主要成分的分子量在1006至1034道尔顿之间。脂质部分包含14种直链和支链β-羟基脂肪酸的混合物，其大小从C12到C17不等。每个分子含有7个氨基酸。肽部分由以下氨基酸组成：谷氨酸作为N端氨基酸，天冬酰胺、缬氨酸、亮氨酸，异亮氨酸作为C端氨基酸，其比例分别为1.1:1.1:1.0:2.8:1.0。纯化后的地衣溶素A可将水的表面张力从72毫牛/米降低至28毫牛/米，并且在低至12毫克/升的浓度下就能达到临界胶束浓度，这表明该产品是一种强大的表面活性剂，与其他表面活性剂相比具有优势。地衣溶素A的抗菌活性也已得到证实。
