Methionine is an essential amino acid that cannot be synthesized in an animal’s body. It is widely used as a feed additive in livestock industry, mainly for poultry feed to increase productivity of chicken meat and eggs as poultry feed, which is made mainly from corn, often does not contain sufficient amounts of methionine. Adding methionine and producing a proper balance of amino acids in feed also helps the poultry to absorb the amino-acids efficiently, thus reducing nitrogen compounds in poultry excrement, which are a source of greenhouse gas emission.