Abstract Sequential fill-and-draw fermentation strategy provides an approach to increase the productivity by replenishing nutrients and minimizing the toxic effects of by-products. In the present work, the same strategy was adopted using lignocellulosic industrial rice-straw C6 hydrolysate stream to produce rhamnolipids from Achromobacter sp. (PS1) in a 6 L bioreactor with a working-volume of 2 L. The production results showed overall rhamnolipid production of 22.03 g/L in 15 days observed at par with 19.35 g/L obtained under shake flask conditions in 18 days. At each sequential feed (2 % sugars), a rise in dissolved oxygen (D.O) concentration was observed in the range between 60–53 % which declined to 47–39 % with consecutive depletion in sugar concentration under no D.O control. For maximum extraction of rhamnolipids from culture broth, the synergistic effect of sweep floc-coagulation using FeCl3 at 0.4 % (w/v) followed by its acidification and solvent extraction was adopted which resulted in maximum recovery of 97.5 % compared to 89.05 % recovery obtained in simply acidification followed by solvent extraction. The characterization of partially purified biosurfactant using tandem-MS revealed six-congeners, Rha-C10-C10 and Rha-Rha-C10-C10 being the most abundant. Oil recovery of 92.21 % from motor-oil impregnated sand using crude rhamnolipid further added the value to the biosurfactant.

中文翻译：

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使用顺序（填充和抽吸）方法在生物反应器中使用扫絮絮凝和酸化工业木质纤维素水解产物生产的鼠李糖脂的协同提取

摘要 连续充填发酵策略提供了一种通过补充营养物质和尽量减少副产品的毒性影响来提高生产力的方法。在目前的工作中，采用相同的策略使用木质纤维素工业稻草 C6 水解产物流从无色杆菌属生产鼠李糖脂。(PS1) 在工作容积为 2 L 的 6 L 生物反应器中。生产结果显示在 15 天内观察到的总鼠李糖脂产量为 22.03 g/L，与在摇瓶条件下在 18 天内获得的 19.35 g/L 持平。在每次连续进料（2% 糖）时，观察到溶解氧 (DO) 浓度升高 60-53%，在没有 DO 控制的情况下，随着糖浓度的连续消耗，溶解氧 (DO) 浓度下降到 47-39%。为了最大限度地从培养液中提取鼠李糖脂，采用 0.4% (w/v) 的 FeCl3 进行吹扫絮凝，然后进行酸化和溶剂萃取的协同效应，与简单酸化后进行溶剂萃取的回收率 89.05% 相比，最大回收率为 97.5%。使用串联质谱对部分纯化的生物表面活性剂进行表征揭示了六种同源物，Rha-C10-C10 和 Rha-Rha-C10-C10 是最丰富的。使用粗鼠李糖脂从机油浸渍砂中的石油回收率为 92.21%，进一步增加了生物表面活性剂的价值。使用串联质谱对部分纯化的生物表面活性剂进行表征揭示了六种同源物，Rha-C10-C10 和 Rha-Rha-C10-C10 是最丰富的。使用粗鼠李糖脂从机油浸渍砂中的石油回收率为 92.21%，进一步增加了生物表面活性剂的价值。使用串联质谱对部分纯化的生物表面活性剂进行表征揭示了六种同源物，Rha-C10-C10 和 Rha-Rha-C10-C10 是最丰富的。使用粗鼠李糖脂从机油浸渍砂中的石油回收率为 92.21%，进一步增加了生物表面活性剂的价值。