Improving Product Specificity of Whole-Cell Alkane Oxidation in Nonconventional Media: A Multivariate Analysis Approach.

Two-liquid-phase reaction media have long been used in bioconversions to supply or remove hydrophobic organic reaction substrates and products to reduce inhibitory and toxic effects on biocatalysts. In case of the terminal oxyfunctionalization of linear alkanes by the AlkBGT monooxygenase the excess alkane substrate is often used as a second phase to extract the alcohol, aldehyde, and acid products. However, the selection of other carrier phases or surfactants is complex due to a large number of parameters that are involved, such as biocompatibility, substrate bioavailability, and product extraction selectivity.

Customized microscale approach for optimizing two-phase bio-oxidations of alkanes with high reproducibility.

Background: Numerous challenges remain to achieve industrially competitive space-time yields for bio-oxidations. The ability to rapidly screen bioconversion reactions for characterization and optimization is of major importance in bioprocess development and biocatalyst selection; studies at conventional lab scale are time consuming and labor intensive with low experimental throughput. The direct ω-oxyfunctionalization of aliphatic alkanes in a regio- and chemoselective manner is efficiently catalyzed by monooxygenases such as the AlkBGT enzyme complex from Pseudomonas putida under mild conditions.

Scalable preparation of -biocatalysts by use of a fluidized-bed reactor.

-biocatalysts are immobilized enzyme preparations with an outstanding robustness against leaching and mechanical stress and therefore promising tools for technical synthesis. They consist of a composite material made from a solid enzyme carrier and silicone. In this study, a method has been found to enable provision of these catalysts in large scale.

The Power of Biocatalysis: A One-Pot Total Synthesis of Rhamnolipids from Butane as the Sole Carbon and Energy Source.

Microbially derived surfactants, so-called biosurfactants, have drawn much attention in recent years and are expected to replace current petrochemical surfactants, owing to their environmental and toxicological benefits. One strategy to support that goal is to reduce production costs by replacing relatively expensive sugars with cheaper raw materials, such as short-chain alkanes. Herein, we report the successful one-pot total synthesis of rhamnolipids, a class of biosurfactants with 12 stereocenters, from butane as sole carbon and energy source through the design of a tailored whole-cell biocatalyst.

Immobilised lipases in the cosmetics industry.

Commercial products for personal care, generally perceived as cosmetics, have an important impact on everyday life worldwide. Accordingly, the market for both consumer products and specialty chemicals comprising their ingredients is considerable. Lipases have started to play a minor role as active ingredients in so-called 'functional cosmetics' as well as a major role as catalysts for the industrial production of various specialty esters, aroma compounds and active agents.

The metagenome-derived enzymes LipS and LipT increase the diversity of known lipases.

Triacylglycerol lipases (EC 3.1.1.

Simultaneous determination of mono-, di-, and triglycerides in multiphase systems by online Fourier transform infrared spectroscopy.

Glycerides are of significant value for industry as ingredients with different purposes in food or cosmetics. The analysis of glycerides is mainly performed by gas chromatography (GC) or high-pressure liquid chromatography (HPLC), which demonstrate limitations in dealing with multiphase systems. In this article, an in situ differentiation between mono-, di-, and triglycerides in multiphase systems by Fourier transform infrared (FT-IR) spectroscopy is demonstrated.

Online monitoring of biotransformations in high viscous multiphase systems by means of FT-IR and chemometrics.

In unstable emulsion systems, the determination of concentrations is a challenge. The use of standard methods like GC, HPLC, or titration is highly inaccurate and makes the acquisition of precise data for these systems complex. In addition, the handicap of high viscosity often comes into play.

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 versatile toolbox for variable DNA functionalization at high density.

To broaden the applicability of chemically modified DNAs in nano- and biotechnology, material science, sensor development, and molecular recognition, strategies are required for introducing a large variety of different modifications into the same nucleic acid sequence at once. Here, we investigate the scope and limits for obtaining functionalized dsDNA by primer extension and PCR, using a broad variety of chemically modified deoxynucleotide triphosphates (dNTPs), DNA polymerases, and templates. All natural nucleobases in each strand were substituted with up to four different base-modified analogues.

Functional tuning of nucleic acids by chemical modifications: tailored oligonucleotides as drugs, devices, and diagnostics.

Chemical modifications of nucleic acids present vast opportunities for extending the functions and properties of these biomolecules. In general, efforts invested in this direction pertain to the introduction of reactive functional groups for further derivatizations of oligonucleotides with numerous reporter groups and for equipping nucleic acids with catalytic chemical moieties. This review deals with representative chemical modifications in the nucleobases, sugars, and the phosphate ester backbone and their application from novel catalytic RNA selection to nucleic acid-based biosensors.

Functionalized DNA: A New Replicable Biopolymer.

New DNA: By enzymatic polymerization of base-modified nucleoside triphosphates, a functionalized DNA (fDNA; see picture) was generated in which every base bears an additional amino acid like residue, thus mimicking the functional group repertoire of peptides on a nucleic acid backbone. These modified oligonucleotides can in turn serve as templates for polymerase chain reaction amplification, thus utilizing fDNA as a novel class of biopolymers for in vitro selection techniques.