Wan C.Chen S.Wen L.Liu X.Lee D.-J.Yang X.2019-05-142019-05-14201620462069https://scholars.lib.ntu.edu.tw/handle/123456789/408229This study newly isolated a bacterial stain of Bacillus flexus S1 which had abilities of synthesizing lipopeptides without any inductive operations, and thus it could effectively save operational procedures or cost. This microorganism produced 1.53 g L-1 of lipopeptides with a basal medium, which was 2.59-fold higher than that with an inductive medium. Meanwhile, the sfp gene was highly expressed under non-inductive conditions. The results firstly noted micellization characteristics of a biosurfactant, including a 46.04 mg L-1 critical micelle concentration, the main chemical structure, and micelles mainly distributing at 30.2-52.5 nm and 181.9-239.9 nm. The lipopeptides indicated good stability over a temperature range of 30-50 ¢XC and pH range of 6-9. Furthermore, monatomic (K+ and Na+) and divalent (Ca2+ and Mg2+) ions respectively alleviated generating smaller and bigger micellar aggregates. The lipopeptides could effectively increase the solubility of hydrophobic organic carbons. As the lipopeptides were adopted together with oil-degrading bacteria, it increased the hydrophobicity of bacterial cells by 1.92-3.04 fold, and had low toxicity to bacterial cells. This study not only provided a new lipopeptides producing bacterium which did not need any conductive operations, but also systematically investigated the characteristics of lipopeptides, providing impactful significance for commercial application. ? 2016 The Royal Society of Chemistry.journal article10.1039/c6ra17510d2-s2.0-84987652768https://www.scopus.com/inward/record.uri?eid=2-s2.0-84987652768&doi=10.1039%2fc6ra17510d&partnerID=40&md5=3d9699ebc6843bcbec3d7e5376f660ac