When a century ago researchers started to work with enzymes, microorganisms, or cell extracts as biocatalysts (i.e., biochemical catalysts) they never imagined that this field will become one of the most exciting and innovative research subjects in the last years. Biocatalysts were originally described as natural substances (i.e., enzymes) that initiate or modify the rate of a chemical reaction in a live body. Nowadays,this term is far broader because the use of protein engineering techniques to assist in the creation of enzymes for unusual intermediates in synthetic chemistry, as well as the advance of molecular biology, high-throughput tools, and bioinformatics that help to overcome new complex issues. Science progresses quickly in areas related to the development of novel biocatalytic methods, including biocatalytic retro synthesis, modular biocatalysts, bioinformatics, molecular biology, nanoscale methodologies, protein engineering, molecular design, and advanced X-ray techniques. Biocatalysts play a prominent role in the quest for new solutions to existing problems such as new vaccines for chronic diseases, decrease of environmental pollution, new environmentally friendly fuels, stronger and biodegradable materials, and purification of contaminated water.