Institute for Biological Interfaces 1, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.
Department of Microbiology, University of Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22138-22150. doi: 10.1021/acsami.2c03337. Epub 2022 May 4.
Biocatalysis in flow reactor systems is of increasing importance for the transformation of the chemical industry. However, the necessary immobilization of biocatalysts remains a challenge. We here demonstrate that biogenic magnetic nanoparticles, so-called magnetosomes, represent an attractive alternative for the development of nanoscale particle formulations to enable high and stable conversion rates in biocatalytic flow processes. In addition to their intriguing material characteristics, such as high crystallinity, stable magnetic moments, and narrow particle size distribution, magnetosomes offer the unbeatable advantage over chemically synthesized nanoparticles that foreign protein "cargo" can be immobilized on the enveloping membrane via genetic engineering and thus, stably presented on the particle surface. To exploit these advantages, we develop a modular connector system in which abundant magnetosome membrane anchors are genetically fused with SpyCatcher coupling groups, allowing efficient covalent coupling with complementary SpyTag-functionalized proteins. The versatility of this approach is demonstrated by immobilizing a dimeric phenolic acid decarboxylase to SpyCatcher magnetosomes. The functionalized magnetosomes outperform similarly functionalized commercial particles by exhibiting stable substrate conversion during a 60 h period, with an average space-time yield of 49.2 mmol L h. Overall, our results demonstrate that SpyCatcher magnetosomes significantly expand the genetic toolbox for particle surface functionalization and increase their application potential as nano-biocatalysts.
生物催化在流动反应器系统中对于化学工业的转化越来越重要。然而，生物催化剂的必要固定化仍然是一个挑战。我们在这里证明，生物磁纳米粒子，即所谓的磁小体，是开发纳米级颗粒制剂的一种有吸引力的选择，可以在生物催化流动过程中实现高且稳定的转化率。除了具有高结晶度、稳定的磁矩和窄的颗粒尺寸分布等有趣的材料特性外，磁小体相对于化学合成的纳米颗粒具有无与伦比的优势，即可以通过遗传工程将外来蛋白质“货物”固定在包膜上，从而稳定地呈现于颗粒表面。为了利用这些优势，我们开发了一种模块化连接器系统，其中丰富的磁小体膜锚通过 SpyCatcher 偶联基团进行基因融合，允许与互补的 SpyTag 功能化蛋白进行有效的共价偶联。这种方法的多功能性通过将二聚酚酸脱羧酶固定到 SpyCatcher 磁小体上得到证明。功能化的磁小体表现出稳定的底物转化，在 60 小时内的时空产率为 49.2 mmol L h，优于同样功能化的商业颗粒，证明了其性能更优。总的来说，我们的结果表明，SpyCatcher 磁小体显著扩展了颗粒表面功能化的遗传工具包，并增加了它们作为纳米生物催化剂的应用潜力。
