Effect of lipase on removal of lard from a cotton fabric by detergency was studied in detail by radioisotope and X-ray microanalysis over 60-min washing. Osmium tetroxide was used to label the soil for microscopy. Backscattered electron images were used to study residual soil present on and within the cotton fibers and in the interfiber spaces of the yarn bundle. Lard-soiled samples had large deposits on the fabric surfaces; oil was present in the crenulation, secondary walls, and the lumen of the fibers. Relative concentrations of oil were determined for selected morphological locations within the fiber structure and at the fiber surface using X-ray microanalysis. Specimens soiled with lard and tagged with osmium tetroxide immediately from the wash bath at 0, 5, 10, 20, and 60 min provide snapshots of the washing process. Within the yarn structure, domains with high oil concentration developed during washing. These domains were not adsorbed onto the fiber surfaces, but were contained within the twisted yarn structure. The inclusion of lipase "accelerates" the washing process with the dislodgment of the soil from the fiber surface being more complete for the yarn specimens washed with lipase for 20 and 60 min. The three main stages of the soil-removal process-transport of water and detergent to the soil on the substrate, separation of soil and substrate, and transport of dislodged soil into the wash bath-were observed. Lipase functions in detergency by hydrolysis of triglycerides forming mono-and diglycerides and fatty acids that are more soluble in water, can undergo soap formation, enhance mesomorphic phase formation, and increase emulsification. The quantification of the mass of the residual oil is well-defined using the radioisotope methodology. The effectiveness of lipase on removal of lard stains is observed at all points in the washing cycle (5, 10, 20, 60 min). Our data fit a classical kinetic description of the soil-removal process described by an exponential decay, with the presence of lipase greatly increasing the rate of oil removal during the early period of washing (0 to 20 min). With the use of lipase in the washing bath, the amount of soil removal after 10 min is about the same as observed after washing 60 min with detergent only. Washing removes soil located on the fibers and yarns on the fabric surfaces early in the process and more completely. Soil that is located within the yarn structure is removed by washing but this requires more time, and lard removal from these interfiber capillaries is greatly enhanced by use of lipase. Washing does remove soil from within the cotton fiber, i.e., secondary wall and lumen, and this is also more complete with the use of lipase. After washing with a detergent for 60 min, the highest concentration of residual soil is in the lumen, although the concentration has been reduced by a factor of two. It appears that the lumen is the last region of the cotton fabric structure to be cleaned by laundering. The use of lipase in the wash bath increased the rate of soil ...
Fatty stain removal is enhanced by the inclusion of lipase in washing compounds and leads to increased lipid removal from within the fibers. Cotton fabrics with varied morphology/chemistry were investigated to study the accessibility of soil in textiles to detergent and lipase. Three cotton fabrics (untreated, mercerized, and carboxymethylated cotton), differing in chemical accessibility, and Tencel™ lyocell fabric, a microdenier manufactured cellulosic fiber, were subjected to three treatments-unwashed, washed with detergent, and washed with lipase-so as to understand further the effects of fiber morphology on lipase effectiveness. Both detergents and lipase removed more soil from the more chemically accessible and hydrophilic textiles. Lipase increased lipid removal for all fabrics and all morphological locations on the fiber, including fiber surfaces, interfiber capillaries, small capillaries, and the center of the yarn bundle. Lipase removed significant quantities of soil from the lumen in untreated and mercerized cottons; these fabrics showed the largest total increases in amount of lipid removed by lipase. When the fiber surfaces were smoother and the fiber structure was less open and not carboxymethylated, i.e., the mercerized cotton fabric, more lipase benefit was observed (72% of the residual soil left after washing with detergent was removed when lipase was added). The total soil removal from the mercerized cotton fabric by use of lipase was equal to that observed for the more open, hydrophilic carboxymethylated fabric and for the Tencel, which has no lumen or other morphological features of natural cotton such as crenulations. Lipase appeared to enhance lipid removal under conditions where removal by the detergent surfactant system was limited. Furthermore, we concluded that lipase acted to remove lipid soil from within the fibers by functioning at the interior surfaces of microfibrils and pores within the fiber structure at the lipid-water interface.Lipases are added to laundry detergents to enhance removal of lipid soils from fabric by catalyzing the breakdown of fats and oils with subsequent release of fatty acids, diacylglycerols, monoglycerols, and glycerol. New methods of lipase modification by genetic engineering have resulted in improved performance of lipases in detergency (1,2). In our joint research, the overall objective was to evaluate the distribution of lipid on fiber with respect to washing with lipase. We have been concerned with the removal of selected fatty stains from cotton (3) and the efficiency of the lipase during the time of the washing (4) with the purpose of further understanding the functioning of lipase in lipid soil removal in laundry.In the evaluation of three lipid soils, we found high concentrations of lard, artificial sebum, and olive oil in the interfiber capillaries of the yarn structure (3). The three soils were distributed differently owing to their wicking properties. Washing with detergent lowered the concentration of oily soil on the fiber surfaces and in the in...
Background:: Microbial phytases are added to animal feed to hydrolyze phytic acid (myo-inositol hexakisphos-phate, IP6) and phytate (salt of phytic acid), increasing phosphorus bioavailability. Novel phytases with enhanced bio-effi-cacy are being developed. Objective:: To characterize the biochemical and enzymatic properties of a novel consensus bacterial 6-phytase and its variant (PhyG), produced in Trichoderma reesei. Methods:: The in vitro specific activity, kinetic parameters, pH-activity profiles (relative to pH5.5), IP6 degradation, hydrol-ysis products and phosphate release of the phytases was determined using sodium phytate substrate. Melting point (Tm) was determined by differential scanning calorimetry and thermostability assessed by measurement of residual activity at different temperatures. In vivo effects of PhyG supplementation at 0 to 1,000 FTU/kg on ileal IP6 digestibility and IP ester concentrations were determined in piglets. Results:: Both phytases exhibited pH optima of 3.5–4.5, high relative activity over a wide pH range (pH2.0-5.0), and sub-stantial relative activity at pH1.5. At pH3.0, the specific activity of the PhyG variant was 1487 U/mg protein and at pH3.5 the kinetic constants were 240 μM (Km) and 1873 s-1 (Kcat). Hydrolysis of IP6 by both phytases was rapid. The major initial hydrolysis product was DL-I(1,2,3,4,5)P5, designating the phytases as bacterial 6-phytases (EC 3.1.3.26). Hydrolysis oc-curred at the D-3 (L-1) position in ~30% of instances, indicating a dual-specificity. Both phytases showed high thermosta-bility compared to wild type and existing commercial bacterial 6-phytases; PhyG exhibited 95% residual activity after 20 min incubation at 85.4ºC (pH5.5), Tm50 of ~93.2ºC and Tm of 98.8ºC. In vivo, PhyG at 1,000 FTU/kg achieved an ileal digestibility of IP6 of 89.3%.
Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross‐sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X‐ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.