Motoi Minagawa

Studies on applications of lipolytic enzyme in detergency I. Effect of lipase fromCandida cylindracea on removal of olive oil from cotton fabric

To investigate the effect of lipolytic enzyme on removal of triglyceride soils in laundry, the removal of olive oil from cotton fabric was examined by washing with an aqueous solution of lipase fromCandida cylindracea with and without surfactants at various washing temperatures and times.It was proved that, at optimum conditions, the removal of olive oil with the addition of lipase was 15 to 20% higher than without lipase. Therefore, it might be expected that lipase will be applied in the laundry detergents in practice.

Quantitative determination of Tri-, Di-,monooleins and free oleic acid by the thin layer chromatography-flame lonization detector system using internal standards and boric acid impregnated chromarod.

The separation conditions for hydrolysates of triglycerides by lipase and their quantitative determination are discussed for a thin layer chromatography-flame ionization detector system utilizing internal standards. The complete separation of glyceride hydrolysis mixtures (triolein 1,3-diolein, 1,2-diolein, 1-monoolein and oleic acid) was achieved on a 3% boric acid-impregnated Chromarod S-II by development with benzene/chloroform/acetic acid (70∶30∶2, v/v/v) (mobile phase A) or hexane/ ether/acetic acid (70∶30∶1, v/v/v) (mobile phase B). Mobile phase B had an advantage over mobile phase A in terms of free space to add internal standards for simultaneous quantitation and was employed.p-Hydroxybenzoic acid andp-carboethoxy benzyl alcohol, which appeared between 1,2-diolein and 1-moloolein, were adopted as the internal standards. The calibration curves relating internal standards to each glyceride were all approximated by the equations Y=aXb giving high correlations. The method was applied to hydrolysis of triolein by pancreatic lipase.

Studies on applications of lypolytic enzymes in detergency II. Evaluation of adaptability of various kinds of lipases in practical laundry conditions

Kinetic parameter of hydrolysis, degree of hydrolysis, pH and temperature characteristics and positional specificity of hydrolysis of seven kinds of lipases from various microorganisms and a pancreatic lipase were examined for triolein or olive oil emulsion as a substrate and the adaptability of lipases for laundry systems was evaluated on the basis of these properties.As a result, it was found that lipases from yeast ofCandida cylindracea (Lipase MY® and OF®) were excellent in kinetic parameter and degree of hydrolysis and temperature characteristics and had no positional specificity, and that lipases from mold ofMucor (Lipase M-AP® and SP®) were excellent in pH and temperature characteristics and had positional specificity. On the viewpoint of the present laundry practice under alkaline conditions and the tendency toward low temperature washing, lipases fromCandida andMucor seem to be more suitable for laundry systems in comparison with lipases from other microorganisms and a pancreatic lipase.The effect of positional specificity in hydrolysis of lipase will be discussed on the basis of examination on the removal of triglyceride and its hydrolysates by surfactant solution in a subsequent paper.

Spreading of Liquids in Textile Assemblies Part II: Effects of Softening on Capillary Spreading

The effects of softening agents on the wetting of textiles were investigated by mea suring the capillary spreading of liquid as a function of time. The values of the exponent n during phase II of the capillary spreading of softened fabrics increased in comparison with those of unsoftened fabrics owing to the adsorption of the softening agent, which made the fiber surface more hydrophobic and produced a larger advancing contact angle of the fiber to the water (θ A ). Based on experiments with DTAC as a softening agent for nylon, the following quantitative relationship was found between the value of the exponent n and the advancing contact angle of water (θ A ): n = (4.62 X 10-3)θ A , - 0.001. From this, reasonable advancing contact angles were also estimated for other fabrics.

Fluoroalkylation of polyester by end-capped fluoroalkyl-functional silanes

The surface modification of polyester was examined using both monomeric and oligomeric silanes having end-capped fluoroalkyl groups. From contact angle measurements, the surface free energies of polyester were reduced to 15-20 mJ/m2 for the dispersive component and 1 -3 mJ/m2 for the polar component, respectively, and all the surfaces were shown to be both highly water- and oil-repellent. By XPS (X-ray photoelectron spectroscopy) measurements, using the C l.s peak attributable to the C=O of polyester, the thickness of the siloxane layer on the surface was shown to be less than 5 nm. The solvent durability (resistance) of the modified surfaces was evaluated using contact angle and XPS measurements. Although all the modified surfaces showed durability against dodecane, xylene, ethyl acetate, tetrachloroethylene, and hydrochloric acid, long-time immersion in fluorine-containing solvents reduced the oil repellency of some of the surfaces modified with monomeric or oligomeric silanes having short fluoroalkyls....

Acrylic Acid Grafted Polyester Surface: Surface Free Energies, FT-IR(ATR), and ESCA Characterization:

The surface of polyester grafted with acrylic acid has been characterized using contact angle measurements of a two-liquid phase system and FT-IR and ESCA spectroscopy as a function of the concentration of acrylic acid on grafting. The COOH groups on the polymer surface influence only the polar component γs p of surface energy and not the dispersive one γs d. Both the FT-IR and ESCA characterizations, showing the transformation of COOH to COONa by alkaline treatment, provide information with a high degree of surface sensitivity, comparable to that of contact angle measurements. The relative area ratios of the COONa peak to the COOR peak by FT-IR ( A surface) and of the Na1 s peak to the C1 s peak by ESCA are linearly correlated to γs p.

Repellency of Textile Assemblies Part I: Apparent Contact Angle of Wax-Coated Monofilament Mesh Screen

In a series of studies on the wettability of textile assemblies, apparent contact angles (ϕ) of wax-coated monofilament nylon and polyester mesh screens to water were measured to investigate the effect of the woven structure on the repellency of textiles. Expressions for the liquid-solid and liquid-air interfaces per unit of macroscopic surface area in the Cassie-Baxter equation (f 1 and f2, respectively) have been derived for mesh screens using several models to calculate the apparent contact angles (ϕ A ) theoretically. Comparison with experimental data has shown that the apparent advancing contact angles of water on wax-coated mesh screens can be quantitatively predicted by the Cassie-Baxter equation when the geometrical structure of the surface is accurately defined.

Novel Fluoroalkylation of Polyester Surfaces: Grafting with Perfluoroalkanoyl Peroxides

Perfluoroalkanoyl peroxides such as (C3F7COO)2 have been found to react with polyester film only on the surface. The modified polyester surfaces were characterized by contact angle measurements using a two-liquid phase system and by ESCA spec troscopy. These provided surface free energy values and surface atom content values as a function of reaction time. Perfluoroalkyl groups substituted on the aromatic rings of the polyester surface influenced both the dispersive component γs d of surface free energy and the polar one γS p. The surface free energies decreased with the reaction time and reached a plateau at about 1 hour. There was a large decrease in γS d. Based on the ESCA characterization, the area ratio of the F1 s peak to the O 1 s peak was linearly correlated not only to γ S d but also to γS p.

The effect of builders on the activity of protease enzymes

The effect of builders on the stability of protease enzyme activity was studied in an effort to identify superior builders which are soluble in water and compatible with enzymes formulated into heavy duty laundry powders. Various poly(styrenesulfonate-methacrylate) copolymers, polyacrylate and tripolyphosphate anionic builders, as well as various poly(vinylalcohol-vinylacetate) nonionic copolymers, namely PVAs, were used. Zeolite 4A was also used as a typical nonphosphate particulate builder in the detergents. The protease used is frombacillus stearothermophilus. The calcium content was determined to be 16.7 mole/mole of protease by atomic spectrophotometry.In binary systems composed of a fixed concentration of 10 U/mL protease and varied concentrations of compound, builder or surfacant, it was found that compounds having the larger calcium ion binding capacity (C.B.C.) lowered the relative activity of protease enzyme. The activity of protease enzyme alone was lowered about 20% by addition of 0.02% sodium dodecylbenzene sulfonate (DBS).The anionic builders added to the binary system of fixed 10 U/mL protease and 0.02% DBS reduce the protease enzyme activity in proportion to the magnitude of their C.B.C. Addition of anionic builders further lowered the protease enzyme activity. The nonionic builders and the nonionic surfactant can enhance the protease enzyme activity by protection of protease against the inhibitor, DBS.It is certain that calcium atoms contained in the protease must play an important role for the protease enzyme activity and its stability. Calcium atoms must have a great influence on the formation of protease-substrate complex, protease-compound complex and substrate-compound complex, because the protease, protein substrate and anionic compound would all be negatively charged in alkaline solutions. Builders for enzyme-containing detergents should be constructed to be insensitive to calcium ion.

Surface modification of glass by end-capped fluoroalkyl-functional silanes

Novel oligomeric silanes having end-capped fluoroalkyl groups have been synthesized. The glass surface was modified by oligomeric as well as by monomeric silanes. From contact angle measurements, the surface free energies were determined and the surface was shown to be both highly water- and oil-repellent. Oligomeric-type silanes were more reactive and effective than monomeric-type silanes. A linear correlation was observed between the area ratio of the F 1s peak to the Si 2p peak. The structure of the siloxane layer is discussed in terms of a network interphase model.