NOVELTY - An isolated polynucleotide comprising (a) a nucleotide sequence having a defined sequence 1270 or 1201 base pairs (SEQ ID No. 1 or 13) given in the specification and nucleotide sequence having a defined sequence of any one of 1261 base pairs (SEQ ID No. 4, 6, 8, 9 or 11) given in the specification, or (b) a nucleotide sequence that hybridizes to a complementary sequence of SEQ ID No. 1 or its fragment, is new.    USE - The isolated polynucleotide is useful for producing genetically engineered microorganisms such as Jeotgalicoccus, Corynebacterium, Kokuria, Methylobacterium or Bacillus which is used for producing olefin used in biofuels such as biodiesel, gasoline or jet fuel. The olefin is terminal olefin including nonadecene, methylnonadecene, heptadecene, methylheptadecene, and pentadecene (all claimed).    ADVANTAGE - The isolated polynucleotide has excellent solubility and stability. The genetically engineered microorganism expresses an increased level of polypeptide encoded by the polynucleotide relative to a wild-type microorganism, and thus the olefin can be mass produced effectively. The method is eco-friendly.    DETAILED DESCRIPTION - An isolated polynucleotide comprising (a) a nucleotide sequence having a defined sequence 1270 or 1201 base pairs (SEQ ID No. 1 or 13) given in the specification and nucleotide sequence having a defined sequence of any one of 1261 base pairs (SEQ ID No. 4, 6, 8, 9 or 11) given in the specification, (b) a nucleotide sequence exhibiting at least 70% homology to SEQ ID No. 1, 4, 6, 8, 9, 11 or 13, and encoding a polypeptide comprising a defined sequence of 430 or 361 amino acids (SEQ ID No. 2 or 14) given in the specification or a defined sequence of any one of 421 amino acids (SEQ ID No. 5, 7, 10 or 12) given in the specification, or (c) a sequence encoding a polypeptide having the same biological activity as a polypeptide comprising the amino acid sequence of SEQ ID No. 2, 5, 7, 10, 12 or 14, where the polynucleotide comprises the nucleotide sequence of SEQ ID No. 1 or its fragment, or a nucleotide sequence that hybridizes to a complementary sequence of SEQ ID No. 1 or its fragment, is new. INDEPENDENT CLAIMS are included for the following:    (1) isolated polypeptide having fatty acid decarboxylase activity comprising (a) amino acid sequence of SEQ ID No. 2, 5, 7, 10, 12 or 14, (b) amino acid sequence of SEQ ID No. 2, 5, 7, 10, 12, or 14 with one or more amino acid substitutions, additions, insertions, or deletions, (c) amino acid sequence Phe-X-X-Glu-(VI)-(Arg-Lys)-Arg-X-Tyr-Pro-Phe-(F)-Pro-X-(LIV), where X is any amino acid, and (F) is any amino acid except Phe, (d) amino acid sequence Pro-X(6)-(Leu-Ile)-X(4)-(G)-(VI)-(His-Gln-Met)-X-(Met-Leu-Val)-Asp-Gly-X(2)-His-X(2)-Arg-Lys, where X(n) is X repeated n times, and (G) is any amino acids except Gly, (e) amino acid sequence (Ala-Cys)-(Ala-Gly)-(IV)-(Asp-Glu)-(Ile-Leu)-X-Asn-X(2)-Arg-Pro-X-(VI)-Ala-X(3)-(Phe-Tyr)-X(2)-F-X(3)-Ala-(Leu-Met-Val)-X-(Asp-Glu), (f) amino acid sequence (RK)-X(6)-(Leu-Met-Val)-X(4)-(Ala-Cys)-(Ala-Gly)-(IV)-(Asp-Glu)-(Ile-Leu)-X-Asn-X(2)-Arg-Pro-X-(VI)-Ala-X(3)-(Phe-Tyr)-X(2)-Phe-X(3)-Ala-(Lys-Met-Val)-X-(Asp-Glu), where (RK) is any amino acid except Arg and Lys, or (g) fragment of the above polypeptide including at least 50 amino acids;    (2) recombinant vector comprising the above polynucleotide;    (3) host cell comprising the recombinant vector;    (4) genetically engineered microorganism comprising an exogenous control sequence stably incorporated into the genomic DNA of the microorganism upstream of a polynucleotide comprising a nucleotide sequence having at least 70% sequence identity to SEQ ID No. 1, 4, 6, 8, 9, 11 or 13;    (5) polypeptide produced by the above host cell;    (6) method of producing an olefin, involves culturing the host cell under conditions sufficient to allow expression of the polypeptide, contacting a substrate with an isolated polypeptide having the same biological activity as a polypeptide comprising the amino acid sequence of SEQ ID No. 2, 5, 7, 10, 12, or 14, or contacting a substrate with an isolated polypeptide encoded by the above polynucleotide; and    (7) olefin produced by the above method.