Influence of organic solvents on cutinase stability and accessibility to polyamide fibers

The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli

Escherichia coli (E. coli) was used to activate hydrolysis reaction along with biodegradation in natural and synthetic fibers to identify possibilities as alternative substitutes for textile wastes using chemical solutions and enzymes. To confirm the reaction between the bacterial infections of E. coli and the excessively abundant interstitial spaces of the fibers, various types of natural and synthetic fibers such as cotton, wool, polyethylene terephalate (PET), polyadmide (PA), polyethylene (PE), and polypropylene (PP) were used to confirm the physico-chemical reactions. Tensile strength analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle analysis were used to determine the physico-chemical property changes of the fiber by the bacteria. When biofilm was formed on the fiber surface, various physical changes such as the following were observed: (i) in the analysis of tensile strength, all except PA and PP were decreased and a decrease in cotton fibers was noticeable (ii) depending on the type of fibers, the degree of roughness was different, but generally the surface became rough. In this study, the change of roughness was the most severe on the cotton fiber surface and the change of PET and PA fiber was relatively small. It was found that the intensity peak of oxygen was increased, except for the in cases of PA and PP, through the change of chemical properties by XPS analysis. Changes in topographical properties on the surface through contact angle analysis were stronger in hydrophilic properties, and in the case of cotton, completely hydrophilic surfaces were formed. Through this study, PA and PP fibers, which are Olefin fibers, were theoretically free of physicochemical and topographical changes since there were no functional groups that could trigger the hydrolysis reaction.

Direct enzymatic acylation of cellulose pretreated in BMIMCl ionic liquid

Cellulose esters are an important class of functional biopolymers with great interest in the chemical industry. In this work the enzymatic acylation of Avicel cellulose with vinyl propionate, vinyl laurate and vinyl stearate, has been performed successfully in a solvent free reaction system. At first cellulose was putted into the ionic liquid BMIMCl (1-n-butyl-3-methylimidazolium chloride) in order to facilitate the unwrap of the structure of the polysaccharide molecule and make it accessible to the enzyme. Thus, after this pretreatment the enzymatic esterification reaction was performed using various hydrolases. The enzymes capable of catalyzing the acylation of cellulose were found to be the immobilized esterase from hog liver and the immobilized cutinase from Fusarium solani, while the lipases used did not show any catalytic activity. Cellulose esters of propionate, laurate and stearate were synthesized with a degree of esterification of 1.9%, 1.3% and 1.0%, respectively. It is the first successful direct enzymatic acylation of cellulose with long chain fatty acids.

Using a nitrilase for the surface modification of acrylic fibres

The surface of an acrylic fibre was modified with a commercial nitrilase (EC 3.5.5.1). The effect of fibre solvents and polyols on nitrilase catalysis efficiency and stability was investigated. The nitrilase action on the acrylic fabric was improved by the combined addition of 1 M sorbitol and 4% N, N-dimethylacetamide. The colour levels for samples treated with nitrilase increased 156% comparing to the control samples. When the additives were introduced in the treatment media, the colour levels increased 199%. The enzymatic conversion of nitrile groups into the corresponding carboxylic groups, on the fibre surface, was followed by the release of ammonia and polyacrylic acid. A surface erosion phenomenon took place and determined the "oscillatory" behaviour of the amount of dye uptake with time of treatment. These results showed that the outcome of the application of the nitrilase for the acrylic treatment is intimately dependent on reaction media parameters, such as time, enzyme activity and formulation.

New model substrates for enzymes hydrolysing polyethyleneterephthalate and polyamide fibres

Recently the potential of enzymes for surface hydrophilisation and/or functionalisation of polyethyleneterephthalate (PET) and polyamide (PA) has been discovered. However, there was no correlation between enzyme class/activity (e.g. esterase, lipase, cutinase) and surface hydrolysis of these polymers and consequently no simple assay to estimate this capability. Enzymes active on the model substrates bis (benzoyloxyethyl) terephthalate and adipic acid bishexyl-amide, were also capable of increasing the hydrophilicity of PET and PA. When dosed at the identical activity on 4-nitrophenyl butyrate, only enzymes from Thermobifida fusca, Aspergillus sp., Beauveria sp. and commercial enzymes (TEXAZYME PES sp5 and Lipase PS) increased the hydrophilicity of PET fibres while other esterases and lipases did not show any effect. Activity on PET correlated with the activity on the model substrate. Hydrophilicity of fibres was greatly improved based on increases in rising height of up to 4.3 cm and the relative decrease of water absorption time between control and sample of the water was up to 76%. Similarly, enzymes increasing the hydrophilicity of PA fibres such as from Nocardia sp., Beauveria sp. and F. solani hydrolysed the model substrate; however, there was no common enzyme activity (e.g. protease, esterase, amidase) which could be attributed to all these enzymes.

The effect of additives and mechanical agitation in surface modification of acrylic fibres by cutinase and esterase

The surface of an acrylic fibre containing about 7% of vinyl acetate was modified using Fusarium solani pisi cutinase and a commercial esterase, Texazym PES. The effect of acrylic solvents and stabilising polyols on cutinase operational stability was studied. The half-life time of cutinase increased by 3.5-fold with the addition of 15% N,N-dimethylacetamide (DMA) and by 3-fold with 1M glycerol. The impact of additives and mechanical agitation in the protein adsorption and in the hydrolysis of vinyl acetate from acrylic fabric was investigated. The hydroxyl groups produced on the surface of the fibre were able to react specifically with Remazol Brilliant Blue R (cotton reactive dye) and to increase the colour of the acrylic-treated fabric. The best staining level was obtained with a high level of mechanical agitation and with the addition of 1% DMA. Under these conditions, the raise in the acrylic fabric colour depth was 30% for cutinase and 25% for Texazym. The crystallinity degree, determined by X-ray diffraction, was not significantly changed between control samples and samples treated with cutinase. The results showed that the outcome of the application of these enzymes depends closely on the reaction media conditions.