DECHEMA Research Institute, Frankfurt, Germany.
Phytowelt Greentechnologies GmbH, Nettetal, Germany.
Biotechnol Bioeng. 2021 Jul;118(7):2694-2702. doi: 10.1002/bit.27788. Epub 2021 May 5.
Terpenoids have an impressive structural diversity and provide valuable substances for a variety of industrial applications. Among terpenes, the sesquiterpenes (C ) are the largest subclass with bioactivities ranging from aroma to health promotion. In this article, we show a gram-scale production of the sesquiterpene α-humulene in final aqueous concentrations of 2 g L with the recombinant strain Cupriavidus necator pKR-hum in a fed-batch mode on fructose as carbon source and n-dodecane as an extracting organic phase for in situ product removal. Since C. necator is capable of both heterotrophic and autotrophic growth, we additionally modeled the theoretically possible yields of a heterotrophic versus an autotrophic process on CO in industrially relevant quantities. We compared the cost-effectiveness of both processes based on a production of 10 t α-humulene per year, with both processes performing equally with similar costs and gains. Furthermore, the expression and activity of 3-hydroxymethylglutaryl-CoA reductase (hmgR) from Myxococcus xanthus was identified as the main limitation of our constructed C. necator pKR-hum strain. Thus, we outlined possible solutions for further improvement of our production strain, for example, the replacement of the hmgR from M. xanthus by a plant-based variant to increase α-humulene production titers in the future.
萜类化合物具有令人印象深刻的结构多样性，并为各种工业应用提供了有价值的物质。在萜类化合物中，倍半萜（C ）是生物活性范围从香气到促进健康的最大亚类。在本文中，我们展示了在分批补料模式下，以果糖为碳源，正十二烷为原位产物去除的萃取有机相，在重组菌株 Cupriavidus necator pKR-hum 中以最终水浓度 2 g/L 的规模生产倍半萜 α-葎草烯。由于 C. necator 能够进行异养和自养生长，因此我们还对 CO 作为碳源的异养和自养过程的理论可能产率进行了建模，这在工业相关数量上是可行的。我们根据每年生产 10 t α-葎草烯的情况，比较了这两种工艺的成本效益，发现这两种工艺的成本和收益相当。此外，还确定了来自粘球菌的 3-羟甲基戊二酰辅酶 A 还原酶（hmgR）的表达和活性是我们构建的 C. necator pKR-hum 菌株的主要限制因素。因此，我们概述了进一步改进我们生产菌株的可能解决方案，例如，用植物来源的变体替代粘球菌的 hmgR，以提高未来 α-葎草烯的生产滴度。
