NOVELTY - Method for performing biosynthetic production of 1-alkenes, involves culturing an engineered microorganism in a culture medium, where the engineered microorganism comprises a recombinant 1-alkene synthase comprising an amino acid sequence exhibiting at least 95% sequence identity to a 2720 amino acid sequence (SEQ ID NO: 2) fully defined in the specification.    USE - The method is useful for performing biosynthetic production of 1-alkenes, olefin and alkenes comprising 1-alkenes, where the 1-alkenes are chosen from 1-nonadecene and 1-octadecene, preferably 1-nonadecene (all claimed) which are used as fuel.    ADVANTAGE - The method enables to provide increased yield of 1-alkenes with high purity, and is suitable for industrial production.    DETAILED DESCRIPTION - Method for performing biosynthetic production of 1-alkenes, involves culturing an engineered microorganism in a culture medium, where the engineered microorganism comprises a recombinant 1-alkene synthase comprising an amino acid sequence exhibiting at least 95% sequence identity to a 2720 amino acid sequence (SEQ ID NO: 2) fully defined in the specification, and the amount of the 1-alkenes produced by the engineered microorganism is greater than the amount that produced by an other identical microorganism, cultured under identical conditions, but lacking the recombinant 1-alkene synthase. INDEPENDENT CLAIMS are included for the following:    (1) method for biosynthetic production of an olefin, involves culturing a Cyanobacteria having 1-alkene synthase activity in a culture medium, where the culture medium comprises an exogenous fatty acid, and exposing the engineered Cyanobacteria to light and carbon dioxide for production of an olefin, where the amount of the olefin produced is greater than the amount produced by an other identical Cyanobacteria, cultured under identical conditions but in the absence of the exogenous fatty acid; and    (2) method for biosynthetic production of alkenes, involves culturing an engineered microorganism in a culture medium, where the engineered microorganism comprises a modification which reduces the activity of a hydrolase having an amino acid sequence exhibiting at least 95% sequence identity to a 299 amino acid sequence (SEQ ID NO: 4) fully defined in the specification, and exposing the engineered microorganism to light and carbon dioxide, where the exposure results in the production of alkenes by the engineered microogransims, the alkenes comprise 1-alkenes, and the amount of 1-alkenes produced is greater than the amount produced by an other identical microorganism, cultured under identical conditions, but lacking the modification.