The high cost of biosurfactant production is an obstacle for widespread commercial applications. Cost-effective generation of biosurfactants could be achieved using industrial wastes and by-products as substrates and tailoring cultural conditions. In this work, waste streams including refined waste cooking oil and crude glycerol were compared to each other and to commercial carbon sources. Based on this assessment, the waste cooking oil was selected for further studies. A response surface methodology (RSM) was then used to study biosurfactant production by Acinetobacter calcoaceticus P1-1A strain (a strain indigenous to the North Atlantic Ocean) using the refined waste cooking oil as the sole carbon source. The concentrations of carbon, nitrogen, and NaCl, as well as the initial pH and temperature were varied. The emulsification index was measured as the response. The cultural conditions to reach the maximum emulsification index (68.17%) were 0.0435 v/v (4.35 vol.%) refined waste cooking oil, 6.5 g/L ammonium sulphate, 13.5 g/L NaCl, initial pH of 7.7, and temperature of 34.8°C. The experimental validation of the predicted response under optimum conditions was performed with 862 mg/L of the biosurfactant product generated. The product showed high thermal, pH, and salinity stability. The use of this indigenous bacteria combined with the use of a no-cost carbon source from waste has the potential to not only reduce costs associated with biosurfactant production but also to produce a biosurfactant better suited to treat oil spills in the harsh environment of the North Atlantic and other cold waters.

中文翻译：

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使用废碳源通过天然海洋细菌（醋酸钙不动杆菌 P1-1A）生产生物表面活性剂：工艺条件的影响

生物表面活性剂生产的高成本是广泛商业应用的障碍。使用工业废物和副产品作为基质并定制培养条件，可以实现具有成本效益的生物表面活性剂生产。在这项工作中，包括精炼废食用油和粗甘油在内的废物流相互比较，并与商业碳源进行了比较。基于此评估，选择废食用油进行进一步研究。然后使用响应面方法 (RSM) 研究醋酸钙不动杆菌生产生物表面活性剂P1-1A 菌株（一种原产于北大西洋的菌株）使用精制废食用油作为唯一碳源。碳、氮和 NaCl 的浓度以及初始 pH 值和温度都不同。测量乳化指数作为响应。达到最大乳化指数 (68.17%) 的培养条件是 0.0435 v/v (4.35 vol.%) 精制废食用油、6.5 g/L 硫酸铵、13.5 g/L NaCl、初始 pH 值为 7.7、温度为34.8°C。对最佳条件下的预测响应进行了实验验证，生成的生物表面活性剂产品为 862 mg/L。该产品显示出高的热稳定性、pH 稳定性和盐度稳定性。