This algal enzyme, characterized from the green algae Chlorella variabilis and Chlamydomonas reinhardtii, is dependent on blue light, which photooxidizes its FAD cofactor. The enzyme acts on fatty acids in the range of C12 to C22, with a higher efficiency for C16 to C17 chains, and forms an alkane product that is one carbon shorter than the substrate. The enzyme can also act on unsaturated fatty acids, forming the respective alkenes, but does not generate a new double bond.