Cascade enzymatic synthesis of a statin side chain precursor - the role of reaction engineering in process optimization.

Statins are an important class of drugs used to lower blood cholesterol levels and are often used to combat cardiovascular disease. In view of the importance of safe and reliable supply and production of statins in modern medicine and the global need for sustainable processes, various biocatalytic strategies for their synthesis have been investigated. In this work, a novel biocatalytic route to a statin side chain precursor was investigated in a one-pot cascade reaction starting from the protected alcohol -(3-hydroxypropyl)-2-phenylacetamide, which is oxidized to the corresponding aldehyde in the first reaction step, and then reacts with two equivalents of acetaldehyde to form the final product -(2-((2,4,6)-4,6-dihydroxytetrahydro-2-pyran-2-yl)ethyl)-2-phenylacetamide (phenylacetamide-lactol).

A host-vector toolbox for improved secretory protein overproduction in Bacillus subtilis.

Target proteins in biotechnological applications are highly diverse. Therefore, versatile flexible expression systems for their functional overproduction are required. In order to find the right heterologous gene expression strategy, suitable host-vector systems, which combine different genetic circuits, are useful.

Combining Photo-Organo Redox- and Enzyme Catalysis Facilitates Asymmetric C-H Bond Functionalization.

In this study, we combined photo-organo redox catalysis and biocatalysis to achieve asymmetric C-H bond functionalization of simple alkane starting materials. The photo-organo catalyst anthraquinone sulfate (SAS) was employed to oxyfunctionalise alkanes to aldehydes and ketones. We coupled this light-driven reaction with asymmetric enzymatic functionalisations to yield chiral hydroxynitriles, amines, acyloins and α-chiral ketones with up to 99 % In addition, we demonstrate functional group interconversion to alcohols, esters and carboxylic acids.

Expanding the Halohydrin Dehalogenase Enzyme Family: Identification of Novel Enzymes by Database Mining.

Halohydrin dehalogenases are very rare enzymes that are naturally involved in the mineralization of halogenated xenobiotics. Due to their catalytic potential and promiscuity, many biocatalytic reactions have been described that have led to several interesting and industrially important applications. Nevertheless, only a few of these enzymes have been made available through recombinant techniques; hence, it is of general interest to expand the repertoire of these enzymes so as to enable novel biocatalytic applications.

Cloning, expression and characterization of a eukaryotic cycloalkanone monooxygenase from Cylindrocarpon radicicola ATCC 11011.

In this study, we have cloned and characterized a cycloalkanone monooxygenase (CAMO) from the ascomycete Cylindrocarpon radicicola ATCC 11011 (identical to Cylindrocarpon destructans DSM 837). The primary structure of this Baeyer-Villiger monooxygenase (BMVO) revealed 531 residues with around 45% sequence identity to known cyclohexanone monooxygenases. The enzyme was functionally overexpressed in Escherichia coli and investigated with respect to substrate spectrum and kinetic parameters.

Increasing the synthesis/hydrolysis ratio of aminoacylase 1 by site-directed mutagenesis.

Aminoacylase-1 from pig kidney (pAcy1) catalyzes the highly stereoselective acylation of amino acids, a useful conversion for the preparation of optically pure N-acyl-l-amino acids. The kinetic of this thermodynamically controlled conversion is determined by maximal velocities for synthesis (V(mS)) and hydrolysis (V(mH)) of the N-acyl-l-amino acid. To investigate which parameter affects maximal velocities, we focused on the proton acceptor potential of the catalytic base, E146, and studied the influence of the active site architecture on its contribution to the pKa of residue E146.

Functional expression of porcine aminoacylase 1 in E. coli using a codon optimized synthetic gene and molecular chaperones.

Efficient recombinant expression of N-acyl-L-aminoacylase 1 from pig kidney (pAcy1) was achieved in the prokaryotic host Escherichia coli. An optimized nucleotide sequence (codon adaptation index 0.95 for E.

A potential high-throughput method for the determination of lipase activity by potentiometric flow injection titrations.

Potentiometric FIA titrations were performed to determine enzyme activities of lipase type B from Candida antarctica, CAL-B. Two substrates, triacetin and tributyrin were hydrolyzed in phosphate buffer solutions, and the concentration change of the base component of the buffer was titrated in a carrier solution containing hydrochloric acid and potassium chloride. The system was calibrated with butyric acid and acetic acid, respectively.

Microbiosensors for measurement of microbially available dissolved organic carbon: sensor characteristics and preliminary environmental application.

Microbial respiration-based microbiosensors used for quantification of available dissolved organic carbon (ADOC) instantaneously respired by microorganisms are described. The sensing membranes contained aerobic seawater microorganisms immobilized in a polyurethane hydrogel. Molecular investigations revealed that the bacterial strain used was most closely related to Staphylococcus warneri.