Limonene and its derivatives have great market potential with diverse applications in food, pharmaceuticals, cosmetics, etc. Commercial production of limonene and its derivatives through extraction from plants suffers from the unstable market supply, while chemical synthesis of these compounds is hindered by high energy consumption and pollutant emission. Microbial biosynthesis provides a promising alternative approach for the sustainable supply of limonene and its derivatives. However, low efficiency and specificity of the biosynthetic enzymes and pathways in heterologous hosts make it still challenging for the commercialization of microbial limonene production. On the other hand, the limonene toxicity heavily reduces cellular fitness, which poses a serious challenge for improving limonene titer. Here, we critically review the recent progresses in engineering microbes for limonene biosynthesis and derivation with the emphasis on enzyme characterization and pathway optimization. In particular, we introduce the current trends in microbial limonene decoration for the biosynthesis of bio-active molecules such as α-terpineol and perillyl alcohol. We also discuss the feasible strategies for relieving limonene toxicity and enhancing the robustness of microbial cell factories.

柠檬烯及其衍生物具有巨大的市场潜力，在食品，药品，化妆品等领域具有广泛的应用。通过从植物中提取柠檬烯及其衍生物的商业生产遭受不稳定的市场供应的困扰，而这些化合物的化学合成受到高能耗和污染物排放的阻碍。微生物生物合成为柠檬烯及其衍生物的可持续供应提供了一种有前途的替代方法。然而，异源宿主中生物合成酶和途径的低效率和特异性使其对于微生物柠檬烯生产的商业化仍然具有挑战性。另一方面，柠檬烯的毒性严重降低了细胞的适应性，这对改善柠檬烯的滴度提出了严峻的挑战。这里，我们批判性地回顾了柠檬烯生物合成和衍生工程微生物的最新进展，重点是酶的表征和途径优化。特别是，我们介绍了微生物柠檬烯装饰的当前趋势，以用于生物活性分子的生物合成，例如α-松油醇和紫苏醇。我们还讨论了减轻柠檬烯毒性并增强微生物细胞工厂的稳健性的可行策略。