Synergies of phenolic-acids' surface-modified titanate nanotubes (TiNT) for enhanced photo-catalytic activities.

The adsorption of chemically similar but differently oxygen reactive phenolic-acid derivatives on the Ti-nanotubes (TiNTs) surfaces to increase and/or broaden their photo-induced activity was studied using Raman and X-ray photoelectron spectroscopies combined with zeta-potential analyses. Photo-catalytic activities and stabilities of newly synthesized particles were evaluated by using high-resolution capillary electrophoresis in combination with cyclic voltammetry and spin-trapping EPR spectroscopy. The modification with caffeic acid (CA) resulted in well-oriented and dense but oxygen semi-stable thin layer (1-3 nm) of self-assembled mono-molecular and/or bi-dentate coordinated molecules on the TiNTs' surfaces, which narrowed the band gap from 2.9 eV (for un-modified TiNTs) to 1.55 eV, but however restrict the hydroxyl radicals generation under both UV (320 nm) and VIS (450 nm) source radiations. On the other hand, the gallic acid (GA) resulted in situ polymerized GA layer through bi-dentate binding as highly-oxygen-stabilized surface structure, yielding narrower band gap of 2.25 eV and increased hydroxyl radical's generation under both exposure lights. The third tested hydroxybenzoic acid (HA), resulted to an unstable layer bonded thorough single-hydrogen bonding mechanism. This work offers a new modification strategy for stable (oxygen and photo-induction related) and highly visible-light responded TiNTs as photocatalyst.

Laccase-induced grafting on plasma-pretreated polypropylene.

A new environmentally friendly strategy for the sustainable functionalization of inert man-made polymer surfaces is mapped out for the first time using a combination of plasma pretreatment and enzymatic postgrafting. The efficiency of enzymatic covalent binding is investigated by grafting methacrylate monomers possessing different amino groups, primary, tertiary, and quaternary, onto a polypropylene surface using plasma pretreatment. Subsequent enzymatic grafting, using laccase and guaiacol sulfonic acid (GSA), is determined by surface analytical techniques, such as attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The grafting of GSA in the presence of a laccase is proven by a 10-fold increase in sulfur compared to the control. The covalent coupling between GSA and primary amine groups is determined by HPLC-MS using hexylamine as a model substrate. The advantage of technology is in the strong covalent binding of functional groups onto the synthetic polymer's surface, which could then be suitably tailored by enzymes possessing substrate specificity and regional selectivity.

Enzymatic reduction of azo and indigoid compounds.

A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy.

A new cuticle scale hydrolysing protease from Beauveria brongniartii.

From a screening for the production of new proteases specific for cuticle scales, Beauveria brongniartii was selected producing an alkaline Ca(++) dependent protease. The purified had a molecular weight of 27 kDa and a pI value of 8.0. Substrate specificities of model substrates (wool with partially removed cuticles treated with SDS) were analyzed by protein release, dissolved organic carbon (DOC) and nitrogen analysis. The C/N ratio of released material turned out to be a good parameter to determine the site of action of proteases on fibres. Compared to other enzymes, the fungal protease preferentially hydrolyzed cuticle scales and has thus a potential for anti-shrinking pre-treatment of wool fabrics.