A detergent composition, preferably a manual dishwashing detergent composition comprising a surfactant system and a fatty acid decarboxylase enzyme and method of manually washing soiled articles, comprising the step of: delivering a composition to a volume of water to form a wash liquor and immersing the soiled articles, in the wash liquor, or delivering a composition optionally in the presence of water, directly onto a soiled article, or onto a cleaning implement, and using the cleaning implement to clean the soiled article.