In vivo and in vitro studies on the carotenoid cleavage oxygenases from Sphingopyxis alaskensis RB2256 and Plesiocystis pacifica SIR-1 revealed their substrate specificities and non-retinal-forming cleavage activities.

Carotenoid cleavage oxygenases are nonheme iron enzymes that specifically cleave carbon-carbon double bonds of carotenoids. Their apocarotenoid cleavage products serve as important signaling molecules that are involved in various biological processes. A database search revealed the presence of putative carotenoid cleavage oxygenase genes in the genomes of Sphingopyxis alaskensis RB2256 and Plesiocystis pacifica SIR-1.

Thiol-functionalization of acrylic ester monomers catalyzed by immobilized Humicola insolens cutinase.

Immobilized cutinase HiC from the ascomycete Humicola insolens was applied as a novel biocatalyst for the synthesis of functionalized acryclic esters by transesterification. As a model reaction, transesterification of methyl acrylate with 6-mercapto-1-hexanol at a high molar ratio in a solvent free system was chosen. Besides two minor Michael-addition by-products, 6-mercaptohexyl acrylic ester was identified as the main product with the thiol as the functional end group.

Biosynthesis of zeaxanthin in recombinant Pseudomonas putida.

Pseudomonas putida KT2440 strain was investigated for biosynthesis of the valuable xanthophyll zeaxanthin. A new plasmid was constructed harboring five carotenogenic genes from Pantoea ananatis and three genes from Escherichia coli under control of an L: -rhamnose-inducible promoter. Pseudomonas putida KT2440 wild type hardly tolerated the plasmids for carotenoid production.

Identification of the GDP-N-acetyl-d-perosamine producing enzymes from Escherichia coli O157:H7.

GDP-N-acetyl-d-perosamine is a precursor of the LPS-O-antigen biosynthesis in Escherichia coli O157:H7. Like other GDP-6-deoxyhexoses, GDP-N-acetyl-d-perosamine is supposed to be synthesized via GDP-4-keto-6-deoxy-d-mannose, followed by a transamination- and an acetylation-reaction catalyzed by PerA and PerB. In this study, we have overproduced and purified PerA and PerB from E.