New substrates for reliable enzymes: enzymatic modification of polymers

Recent studies clearly indicate that the modification of synthetic and natural polymers with enzymes is an environmentally friendly alternative to chemical methods using harsh conditions. New processes using lipases, proteases, nitrilases and glycosidases have been developed for the specific non-destructive functionalization of polymer surfaces. The specificity of enzymes has also been exploited in polymer synthesis; for example, lipases have been used for the production of optically active polyesters. Oxidoreductases have been used for the cross-linking and grafting of lignaceous materials and for the production of polymers from phenolics. Recent successes in this area are mainly attributable to advances in the design of reaction systems (e.g. biphasic systems and micellar solutions), while the enzymes are mainly from commercial sources

Enzymes go big : surface hydrolysis and functionalisation of synthetic polymers

Enzyme technology has progressed from the biotransformation of small substrates to biotransformation of synthetic polymers. Important breakthroughs have been the isolation and design of novel enzymes with enhanced activity on synthetic polymer substrates. These were made possible by efficient screening procedures and genetic engineering approaches based on an in-depth understanding of the mechanisms of enzymes on synthetic polymers. Enhancement of the hydrophilicity of synthetic polymers is a key requirement for many applications, ranging from electronics to functional textile production. This review focuses on enzymes that hydrolyse polyalkyleneterephthalates, polyamides or polyacrylonitriles, specifically on the polymer surface thereby replacing harsh chemical processes currently used for hydrophilisation

Enzymes in fibre processing

[Excerpt] Advances in enzymology, genetics and industrial enzyme production make existing technologies using enzymes for fibre processing more attractive and open up new possibilities such as the improvement of synthetic fibers. Together with increasing knowledge about fibre morphology, more efficient processing and higher product quality become feasible. The 3rd International Conference on Biotechnology in the Textile Industry INTB04 held in Graz, Austria from June 13 /16 2004 provided a thorough overview of the current and future focus of enzymology in the materials processing industry. It stimulated discussions between experts from universities, research organizations and industry worldwide. Over 150 participants from 32 countries in 4 continents (one third of all participants coming from industry) ensured that this meeting had a strong impact in the area of biotechnology in materials processing. [...](undefined

"In Situ" enzymatically prepared polymers for wool coloration

Phenolic compounds such as hydroquinone, catechol and ferulic acid can polymerise and therefore develop deep colours when treated with peroxidase and laccase enzymes. We have attempted to apply this phenomenon for wool dyeing. Wool was padded with phenolic compounds and deep colours were developed by enzymatic treatment in buffer solutions. Mordant with chromium compounds or heating under the conditions of acid catalysis was available for fixation of these coloured compounds on the wool fibres.Enzymatically dyed wool samples.[GRAPHICS

Hydrogen peroxide generation with immobilized glucose oxidase for textile bleaching

Glucose oxidase was covalently immobilized on commercially available alumina and glass supports, with a high level of protein recovery. The operational stability of the alumina carrier was an advantage over the glass support, though the rate of generation of hydrogen peroxide in the case of the latter was higher. The immobilization technique provided repeated application of the enzyme even in low concentration, and the hydrogen peroxide generated in the enzymatic reaction was successively used for textile bleaching

Protein interactions in enzymatic processes in textiles

Enzymes are the catalysts of all reactions in living systems. These reactions are catalysed in the active sites of globular proteins. The proteins are composed by amino acids with a variety of side chains ranging from non-polar aliphatic and aromatic to acidic, basic and neutral polar. This fact allows to a globular 3D protein to create in the active site all ranges of microenvironments for catalysis. Major advances in microbial technology and genetics allow recently the broad range of enzymatic applications in the industry. Enzymatic processes have been increasingly incorporated in textiles over the last years. Cotton, wool, flax or starches are natural materials used in textiles that can be processed with enzymes. Enzymes have been used for desizing, scouring, polishing, washing, degumming, peroxide degradation in bleaching baths as well as for decolourisation of dyehouse wastewaters, bleaching of released dyestuff and inhibiting dye transfer. Furthermore many new applications are under development such as natural and synthetic fibres modification, enzymatic dyeing, finishing etc. Most of the textile processes are heterogeneous where an auxiliary as a dye, enzyme, softener or oxidant have to be taken from the solution to the fibre. These processes require the presence of surface-active agents, ionic force “balancers”, buffers, stabilisers and others, and are characterized with high turbulence and mechanical agitation in the textile baths. In this paper it is intended to understand and discuss the major protein interactions within textile processes and to try to anticipate troubleshooting possibilities when enzymes are used. It can be expected that an enzyme protein can interact with all chemical agents in solution due to the large variety of side chains of the outer-amino-acids in the large 3D structure of the protein. Without the aim of being exhaustive various points will be discussed where protein interactions are important for textile processing

Bio-preparation of cotton fabrics

This study attempted to introduce the bio-processes in the conventional scouring and bleaching preparation of cotton. The scouring with two types of pectinases, acting under acidic and alkaline conditions respectively, was as efficient as the chemical process in terms of obtained adequate water absorbency of the fabrics. The necessity of surfactants application in scouring was outlined. Bleaching of the fabrics was performed with hydrogen peroxide, which was enzymatically produced by glucose oxidase during oxidation of glucose. The aeration plays an important role in the enhancement of the enzyme reaction, so that the quantity of generated peroxide is sufficient to overcome the stabilizing effect of the glucose and protein in the subsequent bleaching. A closed-loop process reusing starch containing desizing baths in a single step scouring/bleaching operation with enzyme-generated peroxide was performed. (C) 2001 Elsevier Science Inc. All rights reserved

Laccases to improve the whiteness in a conventional bleaching of cotton

This study reports for the first time on the enhancement of the bleaching effect achieved on cotton using laccase enzyme. Laccases applied in short-time batchwise or pad-dry processes prior to conventional peroxide bleaching, improved the end fabric whiteness. The whiteness level reached in the combined enzymatic/peroxide process was comparable to the whiteness in two consecutive peroxide bleaches. Effect of 10 min laccase pre-treatment at 60 8C, pH 5 on fabrics whiteness before and after a conventional hydrogen peroxide bleaching