Waste-cooking oil (WCO) is defined as vegetable oil that has been used to fry food at high temperatures. The annual global generation of WCO is 41–67 million tons. Without proper treatment, most WCO is abandoned in sinks and the solid residue of WCO is disposed of in landfills, resulting in serious environmental problems. Recycling and valorizing WCO have received considerable attention to reduce its negative impact on ecosystems. To convert WCO into a high value-added compound, we aimed to produce sophorolipids (SLs) that are industrially important biosurfactants, using WCO as a hydrophobic substrate by the fed-batch fermentation of Starmerella bombicola. The SLs concentration was increased ~3.7-fold compared with flask culture (315.6 vs. 84.8 g/L), which is the highest value ever generated from WCO. To expand the applications of SLs, we prepared methyl hydroxy branched fatty acids (MHBFAs) from SLs, which are important chemicals for various industries yet difficult to produce by chemical methods, using a bio-chemical hybrid approach. We synthesized bio-based plastics using MHBFAs as co-monomers. Compared with the control polymer without MHBFAs, even the incorporation of 1 mol% into polymer chains improved mechanical properties (such as ultimate tensile strength, 1.1-fold increase; toughness, 1.3-fold increase). To the best of our knowledge, this is the first attempt to apply MHBFAs from SLs derived from WCO to building blocks of plastics. Thus, we extended the valorization areas of WCO to one of the world’s largest industries.

废烹饪油（WCO）定义为已用于高温油炸食物的植物油。世界海关组织的全球年发电量为4167万吨。未经适当处理，大多数WCO被丢弃在水槽中，WCO的固体残留物被丢弃在垃圾填埋场中，从而导致严重的环境问题。WCO的回收利用和增值已受到相当多的关注，以减少其对生态系统的负面影响。为了将WCO转化为高附加值的化合物，我们的目标是通过将Starcoella bombicola的分批分批发酵法使用WCO作为疏水性底物，生产具有工业重要性的生物表面活性剂槐糖脂（SL）。与烧瓶培养相比，SLs浓度增加了约3.7倍（315.6对84.8 g / L），这是WCO产生的最高值。为了扩大SL的应用范围，我们使用生化混合方法从SL制备了甲基羟基支化脂肪酸（MHBFA），这是各种行业的重要化学品，但化学方法难以生产。我们使用MHBFA作为共聚单体合成了生物基塑料。与没有MHBFA的对照聚合物相比，即使在聚合物链中掺入1 mol％的聚合物也可以改善机械性能（例如极限拉伸强度，增加1.1倍；韧性，增加1.3倍）。据我们所知，这是将源自WCO的SL中的MHBFA应用于塑料构件的首次尝试。因此，