Fusion proteins, understood as those created by joining two or more genes that originally encoded independent proteins, have numerous applications in biotechnology, from analytical methods to metabolic engineering. The use of fusion enzymes in biocatalysis may be even more interesting due to the physical connection of enzymes catalyzing successive reactions into covalently linked complexes. The proximity of the active sites of two enzymes in multi-enzyme complexes can make a significant contribution to the catalytic efficiency of the reaction. However, the physical proximity of the active sites does not guarantee this result. Other aspects, such as the nature and length of the linker used for the fusion or the order in which the enzymes are fused, must be considered and optimized to achieve the expected increase in catalytic efficiency. In this review, we will relate the new advances in the design, creation, and use of fused enzymes with those achieved in biocatalysis over the past 20 years. Thus, we will discuss some examples of genetically fused enzymes and their application in carbon‑carbon bond formation and oxidative reactions, generation of chiral amines, synthesis of carbohydrates, biodegradation of plant biomass and plastics, and in the preparation of other high-value products.

融合蛋白，被理解为通过连接两个或多个最初编码独立蛋白质的基因而产生的蛋白质，在生物技术中具有许多应用，从分析方法到代谢工程。由于催化连续反应成共价连接复合物的酶的物理连接，在生物催化中使用融合酶可能更有趣。多酶复合物中两种酶的活性位点接近可以对反应的催化效率做出重大贡献。然而，活动站点的物理接近并不能保证这个结果。必须考虑和优化其他方面，例如用于融合的接头的性质和长度或酶融合的顺序，以实现预期的催化效率增加。在这篇综述中，我们将把融合酶的设计、创造和使用方面的新进展与过去 20 年在生物催化领域取得的进展联系起来。因此，我们将讨论一些基因融合酶的例子及其在碳-碳键形成和氧化反应、手性胺的生成、碳水化合物的合成、植物生物质和塑料的生物降解以及其他高价值产品的制备中的应用.