Center of Environmental Microbiology and Biotechnology, Autonomous University of Campeche, Colonia Buenavista, San Francisco de Campeche 24039, Campeche, Mexico.
Int J Mol Sci. 2013 Sep 13;14(9):18959-72. doi: 10.3390/ijms140918959.
A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecular weight (700 kDa), non-ionic molecule. Gas chromatography of the lipid fraction revealed the presence of palmitic, stearic, and oleic acids; thus microbactan may be considered a glycolipoprotein. Microbactan emulsified aromatic hydrocarbons and oils to various extents; the highest emulsification index was recorded against motor oil (96%). The stability of the microbactan-motor oil emulsion model reached its highest level (94%) at 50 °C, pH 10 and 3.5% NaCl content. It was not toxic to Artemia salina nauplii. Microbactan is, therefore, a non-toxic and non-ionic bioemulsifier of high molecular weight with affinity for a range of oily substrates. Comparative phylogenetic assessment of the 16S rDNA gene of Microbacterium sp. MC3B-10 with genes derived from other marine Microbacterium species suggested that this genus is well represented in coastal zones. The chemical nature and stability of the bioemulsifier suggest its potential application in bioremediation of marine environments and in cosmetics.
一种先前报道的细菌生物乳化剂，在此称为 microbactan，进一步进行了分析，以表征其脂质成分、分子量、离子特性和毒性，以及其在一系列温度、盐度和 pH 值下对疏水性底物的生物乳化潜力。分析表明，microbactan 是一种高分子量（700 kDa）、非离子分子。脂质部分的气相色谱分析显示存在棕榈酸、硬脂酸和油酸；因此，microbactan 可以被认为是一种糖脂蛋白。microbactan 不同程度地乳化了芳烃和油类；对机油（96%）的乳化指数最高。microbactan-机油乳液模型的稳定性在 50°C、pH 值 10 和 3.5%NaCl 含量下达到最高水平（94%）。它对卤虫无节幼体无毒。因此，microbactan 是一种非毒性、非离子、高分子量的生物乳化剂，对多种油性底物具有亲和力。与其他海洋 Microbacterium 物种的基因相比，对 MC3B-10 海洋微杆菌 16S rDNA 基因的比较系统发育评估表明，该属在沿海地区有很好的代表性。生物乳化剂的化学性质和稳定性表明其在海洋环境生物修复和化妆品中的潜在应用。
