The combination of metal-based catalysts and enzymes represents an inexpensive and environmentally attractive research area 202 . Also, combining transition metal catalysts with engineered or artificial metalloenzymes expands the range of catalyzed reactions and improves their reactivities. The use of olefin metathesis catalyst (Ru complex) in combination with a cytochrome P450 enzyme greatly improved the epoxidation selectivity. Transition metal complexes biocompatible with living organisms were reported to be efficient biocatalysts. For example, iron(III) phthalocyanine facilitates olefin cyclopropanation in the presence of E. coli living microorganisms. Enzymes that attracted the most attention as potential biocatalysts are shown in Figure . Among them are triacylglycerol lipase and lipase CaLB. The hydrolases and oxireductases such as peroxidase, laccase, glucose oxidase, alcohol/glucose dehydrogenase, and carbonyl reductase contribute to this field significantly. Carbon-based materials and transition metals (Ni, Fe, Pt, Cu, Co) are widely used to optimize enzymatic systems which makes them attractive. Nickel and cobalt coordinated covalent organic frameworks were found to exhibit oxidase like properties. Nickel and iron containing metal organic framework nanozymes showed peroxidase like activity for biosensing applications. NiFe hydrogenase catalysts which are immune to inhibition by oxygen were studied recently for hydrogen oxidation reactions, which are traditionally catalyzed by expensive Pt catalysts. This trend shows that the hydrolases and oxireductases are two primary types of biocatalysts and the combination between biocatalysts and metal catalysts is another approach in this field. Nickel and iron metal organic frameworks containing nanozymes showed peroxidase like activity for biosensing applications. Successful application of NiFe hydrogenase enzymes for hydrogen oxidation reaction traditionally catalyzed by expensive Pt had been reported. The substance classes used in biocatalysis are presented in Figure . Enzymes dominate other classes of compounds in both journal and patent publications. Immobilized enzymes are in second place. Immobilizing enzymes provide several benefits such as minimizing enzymes inhibition by the products, reusing the catalysts without the need for separation of the used biocatalysts, and enables establishing continuous flow biocatalysis. Most of the patents involve the application of enzymes and encapsulated enzymes for the synthesis of organic and biomolecules Most of the patents involve the application of enzymes and encapsulated enzymes for the synthesis of organic and biomolecules and conversion of biomass. The other substances broadly used as biocatalysts are porphyrins, enzyme mimics, hemoglobins, and co-enzymes. Porphyrins including metalloporphyrins, their analogues and derivatives exhibit enzyme like properties. Porphyrins are commonly used in electrocatalytic applications. The visible light absorption ability of porphyrin-based compounds enables their application in photocatalytic and photosensitizer applications. Vitreoscilla hemoglobin has been reported as an efficient biocatalyst for organic synthesis. The class of coenzymes represents a special case. Coenzyme includes an organic molecule that binds to the active sites of certain enzymes assisting catalytic reactions. The patent to journal ratio for coenzymes is the highest among the substance classes, showing high commercial interest towards these biocatalysts. The most reported reactions in the biocatalyst publications and their patent-to-journal ratio are shown in Figure . The top reported biocatalyzed reactions are enantioselective synthesis, transesterification, and oxidation. Enantioselective reactions plays a crucial role in synthesis of specific organic molecules, whereas transesterfication has applications in biodiesel and food industry. Biomass hydrolysis and electrochemical reduction are also top reactions catalyzed by enzymes.