At Sylphium Life Sciences Two approaches are in use to produce enzyme libraries. The first method is by making mutants of an enzyme. This can be done by making random mutation in the DNA encoding the whole enzyme. Or by making only random or specific mutations in those regions of the DNA that are known or assumed to be directly involved in the catalytic activity of the enzyme. Also known as site specific (random) mutagenesis. An other approach for obtaining enzyme libraries is by making metagenome libraries from micro-organisms. One of the advantages of metagenome libraries is that without any knowledge of the genome of an organism an expression library can be made in a relatively short period of time.