School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China.
J Agric Food Chem. 2020 Dec 30;68(52):15478-15489. doi: 10.1021/acs.jafc.0c05028. Epub 2020 Dec 15.
Rhamnolipid is the main group of biosurfactants predominantly produced by , a ubiquitous and opportunistic pathogen, which limits its large-scale exploitation. Thus, cost-effective rhamnolipid production from a newly isolated nonpathogenic . UJS-RC was investigated. The highest rhamnolipid production (4.4 ± 0.2 g/L) was achieved in a medium constituting agroindustrial wastes (sugarcane molasses and corn steep liquor) as substrates. Rhamnolipid exhibited reduced surface tension to 72-28 mN/m with an emulsification index of 75%. The structural analyses demonstrated the presence of methoxyl, carboxyl, and hydroxyl groups in rhamnolipid. Mass spectra indicated eight rhamnolipid congeners, where dirhamnolipid (/ 650.01) was the dominant congener. Rhamnolipid inhibited biofilm formation of in a dose-dependent manner, supported by scanning electron microscopy disclosing the disruption of the microcolony/exopolysaccharide matrix. Rhamnolipid's ability to generate reactive oxygen species has thrown light on the mechanism through which the killing of test bacteria may occur.
鼠李糖脂是生物表面活性剂的主要群组，主要由一种普遍存在且机会性的病原体 产生，这限制了其大规模开发。因此，研究了从新分离的非致病性 中经济有效地生产鼠李糖脂。在含有农业工业废物（甘蔗糖蜜和玉米浆）作为底物的培养基中，实现了最高的鼠李糖脂产量（4.4±0.2 g/L）。鼠李糖脂的表面张力降低至 72-28 mN/m，乳化指数为 75%。结构分析表明鼠李糖脂中存在甲氧基、羧基和羟基。质谱表明存在八种鼠李糖脂同系物，其中二鼠李糖脂（/ 650.01）是主要的同系物。鼠李糖脂以剂量依赖的方式抑制 的生物膜形成，扫描电子显微镜显示微菌落/胞外多糖基质被破坏，这为其提供了支持。鼠李糖脂产生活性氧的能力揭示了测试细菌可能被杀死的机制。
