Short branched-chain fatty acids (SBCFAs) are multi-functional platform chemicals used in many fields. Currently, SBCFAs are produced mainly by chemical synthesis, which is high cost and lead to environmental pollution. The aim of this study was to achieve high-level production of SBCFAs from waste materials, bean dreg and crude glycerol. The Bacillus licheniformis DWc9n∗ was genetically modified by overexpression of SBCFAs synthesis genes via replacement of native promoter of bkd operon, the mutant strain DWc9n∗-PbacA produced 4.68 g/L of SBCFAs, increasing by 1.98-fold compared to wild-type strain. SBCFAs concentration was further increased to 7.85 g/L through process optimization. In a 5-L batch fermenter, the mutant showed SBCFAs production with high concentration (8.37 g/L) and productivity (0.20 g/L/h), which is the highest level of SBCFAs production based on low-value substrates fermentation. This is the first study describing efficient SBCFAs production by the modified B. licheniformis strain from bean dreg and crude glycerol.

短支链脂肪酸（SBCFA）是在许多领域中使用的多功能平台化学品。当前，SBCFA主要通过化学合成来生产，这成本高并且导致环境污染。这项研究的目的是从废料，豆渣和粗甘油中大量生产SBCFA。的地衣芽孢杆菌DWc9n *基因上通过的SBCFAs合成的基因的过表达通过置换天然启动子的修饰BKD操纵子中，突变菌株DWc9n * -PbacA产生4.68 g / L的SBCFA，与野生型菌株相比增加了1.98倍。通过工艺优化，SBCFAs的浓度进一步提高到7.85 g / L。在一个5 L的分批发酵罐中，该突变体显示出高浓度（8.37 g / L）和高生产率（0.20 g / L / h）的SBCFAs产量，这是基于低价值底物发酵的最高水平的SBCFAs产量。这是描述由豆渣和粗甘油经改良的地衣芽孢杆菌菌株高效生产SBCFA的第一项研究。