Enzyme, a kind of specialized protein is biocatalyst to accelerate the reaction in living Biosystems by reducing the required activation energy barrier. Without enzymes, any cellular Biosystems cannot sustain its life system anymore. The acceleration of reaction and specificity of enzymes seems almost miracle since reaction rate can be increased up to billion times higher. Nowadays enzymes can be applied for not only living Biosystems but also chemical industries. Very mild reaction conditions such as room temperature, aqueous phase is enough for the synthesis of many kinds of value-added compounds such as pharmaceuticals, cosmetic ingredients and even bulk chemicals by employing enzymes as biocatalysts. However, even though enzymes seem miracle-like, its stability and reaction charac￾teristics may be not optimized to be utilized for the chemical process. Our lab is actively trying to engineer these enzymes to be more optimized and superior biocatalysts capable of converting raw material to value-added compounds through rational and 3D structure-based design of biocatalysts.