β‐caryophyllene is a plant‐derived sesquiterpene and is regarded as a promising ingredient for aviation fuels. Microalgae can convert CO2 into energy‐rich bioproducts through photosynthesis, making them potential platforms for the sustainable production of sesquiterpenes. However, heterologous sesquiterpene engineering in microalgae is still in its infancy, and β‐caryophyllene production in eukaryotic photosynthetic microorganisms has not been reported. In this study, we succeeded in producing β‐caryophyllene in the model eukaryotic microalga Chlamydomonas reinhardtii by heterologously expressing a β‐caryophyllene synthase (QHS). Furthermore, overexpressing the key enzyme of the 2‐C‐methyl‐D‐erythritol 4‐phosphate pathway in the QHS‐expressing strain (QHS‐DXS‐HDR−18) resulted in a 17‐fold higher β‐caryophyllene production compared to the single expression of QHS (QHS−28). Additionally, when isopentenyl diphosphate isomerase (CrIDI) was overexpressed, the β‐caryophyllene production was up to 480.6 μg/L in QHS‐DXS‐HDR‐CrIDI−16 and increased by 1.8‐fold compared to the parental strain QHS‐DXS‐HDR−18. Under photoautotrophic and photomixotrophic conditions in photobioreactors, the β‐caryophyllene production in QHS‐DXS‐HDR‐CrIDI−16 reached 854.7 and 1016.8 μg/L, respectively. Noticeably, all the β‐caryophyllene‐producing strains generated in this study did not exhibit adverse effects on cell growth and photosynthesis activity compared to the untransformed strain. This study demonstrates the first successful attempt to produce β‐caryophyllene in the eukaryotic microalga C. reinhardtii and develops a novel strategy for increasing sesquiterpene production in eukaryotic photosynthetic microorganisms.

中文翻译：

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真核绿色微藻 Chlamydomonas reinhardtii 的航空燃料 β-石竹烯的光生产


β-石竹烯是一种植物来源的倍半萜，被认为是航空燃料的一种很有前途的成分。微藻可以通过光合作用将 CO2 转化为富含能量的生物产品，使其成为可持续生产倍半萜的潜在平台。然而，微藻中的异源倍半萜工程仍处于起步阶段，真核光合微生物中 β-石竹烯的产生尚未报道。在这项研究中，我们通过异源表达 β β-石竹烯合酶 （QHS） 成功地在模型真核微藻 Chlamydomonas reinhardtii 中产生了 -石竹烯。此外，在表达 QHS 的菌株 （QHS-DXS-HDR-18） 中过表达 2-C-甲基-D-赤藓糖醇 4-磷酸途径的关键酶导致 β-石竹烯的产生比 QHS 的单一表达 （QHS-28） 高 17 倍。此外，当异戊烯基二磷酸异构酶 （CrIDI） 过表达时，QHS-DXS-HDR-CrIDI-16 中 β-石竹烯的产量高达 480.6 μg/L，与亲本菌株 QHS-DXS-HDR-18 相比增加了 1.8 倍。在光生物反应器的光合自养和光混合营养条件下，QHS-DXS-HDR-CrIDI-16 中的 β-石竹烯产量分别达到 854.7 和 1016.8 μg/L。值得注意的是，与未转化的菌株相比，本研究中产生的所有产生 β-石竹烯的菌株均未对细胞生长和光合作用活性产生不利影响。本研究展示了在真核微藻 C. reinhardtii 中生产 β-石竹烯的首次成功尝试，并开发了一种增加真核光合微生物中倍半萜产量的新策略。