Kinetic study of lipid distribution after washing with lipases: Microscopy analysis
Kinetic study of lipid distribution after washing with lipases: Microscopy analysis
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用脂肪酶洗涤后脂质分布的动力学研究：显微镜分析
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Marianne Thellersen
中科院分区：
文献类型：
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作者：
S. Obendorf;R. Mejldal;Arindam Varanasi;Marianne Thellersen
采用放射性同位素和X-射线微区分析等方法，研究了脂肪酶对棉织物去污效果的影响。用四氧化三铯标记土壤进行显微镜观察。使用背投电子图像来研究棉纤维上、棉纤维内以及纱束纤维间的残留土壤。被猪油污染的样品在织物表面有大量沉积物；皱纹、次生壁和纤维的管腔中存在油污。用X射线微区分析测定了纤维结构中选定的形态位置和纤维表面的油的相对浓度。在0、5、10、20和60分钟从洗涤槽中立即用猪油弄脏并用四氧化二臭氧标记的标本提供了洗涤过程的快照。在纱线结构内部，在洗涤过程中形成了高含油量的区域。这些结构域没有吸附在纤维表面，而是包含在加捻纱结构中。脂肪酶的加入加速了洗涤过程，对于用脂肪酶洗涤20分钟和60分钟的纱线样品来说，污垢从纤维表面移走得更彻底。观察了土壤去除过程的三个主要阶段--水分和洗涤剂在基质上向土壤的输送，土壤和基质的分离，以及移出的土壤进入洗涤池。脂肪酶通过水解甘油三酯形成单甘酯和双甘油酯来发挥去污作用，脂肪酸在水中更容易溶解，可以形成肥皂，促进中间相的形成，并增加乳化度。用放射性同位素方法很好地确定了剩余油质量的量化。在洗涤周期的各个时间点(5、10、20、60分钟)观察脂肪酶对猪油污渍的去除效果。我们的数据符合指数衰减描述的土壤去除过程的经典动力学描述，在洗涤的早期(0-20min)，脂肪酶的存在极大地提高了除油速度。在洗涤浴中使用脂肪酶，10min后的去污量与仅用洗涤剂洗涤60min后的污垢去除量大致相同。洗涤可在加工初期更彻底地去除织物表面纤维和纱线上的污垢。位于纱线结构内的土壤通过洗涤来去除，但这需要更多的时间，而脂肪酶的使用大大提高了从这些纤维间毛细血管中去除猪油的能力。洗涤确实去除了棉纤维内部的泥土，即次生壁和管腔，这一点在使用脂肪酶时也更完整。在用洗涤剂清洗60分钟后，残留泥土浓度最高的是管腔，尽管浓度降低了两倍。管腔似乎是棉织物结构中最后一个需要通过洗涤来清洗的区域。在洗涤浴中使用脂肪酶可提高棉织物和纤维结构所有部位的去污率。
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. Backscattred 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 removal for all locations with the cotton fabric and fiber structures.