Rhamnolipids are one of the most well-known classes of biosurfactants having wide applications in various industries due to low toxicity, high biodegradability, and environmentally friendly. Dissolved oxygen (DO) concentration has the crucial effect on rhamnolipids production, particularly through fed-batch cultivation. In this study, the effect of different levels of DO concentrations on rhamnolipid production by Pseudomonas aeruginosa in both batch and fed-batch fermentation was investigated in a lab-scale fermenter under precise DO control. A maximal rhamnolipid production of 22.5 g/l was obtained at a DO concentration of 40% in batch fermentation. In order to achieve the high rhamnolipid production, a fed-batch operation under tight DO control of 40% was conducted. As a result, the overall rhamnolipid production and productivity reached to 240 g/l and 0.9 (g/l h), corresponding to a 10.7 and 4.8-fold improvement compared to the batch experiments. The high level of rhamnolipid production via the fed-batch cultivation can be attributed to both DO concentration and the feeding strategy. This achievement is promising for the production of rhamnolipid in industrial scale.

中文翻译：

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在严格的DO控制下，在实验室规模的发酵罐中分批分批培养铜绿假单胞菌生产鼠李糖脂。

鼠李糖脂由于其低毒性，高生物降解性和环境友好性，是在各种工业中具有广泛应用的最著名的生物表面活性剂之一。溶解氧（DO）的浓度对鼠李糖脂的产生具有至关重要的作用，特别是通过分批分批培养。在这项研究中，不同水平的DO浓度对铜绿假单胞菌鼠李糖脂产生的影响在实验室规模的发酵罐中，在精确的溶解氧控制下，研究了分批发酵和分批补料发酵的过程。在分批发酵中，DO浓度为40％时，鼠李糖脂的最大产量为22.5 g / l。为了获得高鼠李糖脂产量，在40％的严格DO控制下进行了分批补料操作。结果，鼠李糖脂的总产量和生产率分别达到240 g / l和0.9（g / l h），与分批实验相比分别提高了10.7和4.8倍。通过补料分批培养生产鼠李糖脂的高水平可归因于DO浓度和补料策略。该成就对于工业规模鼠李糖脂的生产是有希望的。