Influence of microorganisms of fleece on the structure, physical properties, amino acid and mineral composition of sheep wool
Abstract
Wool is an irreplaceable raw material for the textile industry. However, a significant amount of woolen raw material is of low quality. In particular, microbiological destruction of fibers is the most widespread type of damage to wool. In view of this, the aim of our work was to clarify the role of the microflora of sheep fleece in the processes of degradation of the fiber structure and to establish the degree of their chemical and physical changes. The study focused on the wool of ewes from the Askanian fine-wool breed. Microbial analysis was performed by culturing samples on solid nutrient media. The structure was studied using transmission electron microscopy. The keratoses content was determined through the oxidation of wool with superacids. The amino acid composition was analyzed via ion chromatography using an AAA-400 amino acid analyzer. The mineral compos i tion was assessed with an atomic absorption spectrophotometer, model S-115 PC. Fineness was measured using a micrometer, and the tensile strength of the wool was evaluated using a DSh-3M apparatus. It is shown that as a result of the vital activity of the fleece microflora, damage t o the structure of wool fibers occurs, which is accompanied by changes in the surface of the cuticular layer, which is indicated by a probable increase in beta-kerat oses . In such wool, the total amount of amino acids decreases (by 25.6 g/kg, or 2.7%) due decreases in arginine, valine, histidine, lysine and cystine. The reduction of histidine and lysine may be related to the highest content of these amino acids in the cuticular layer, which undergoes significant changes. Wool damaged by microflora is characterized by a reduced level of such mineral elements as c opper and s ulfur. A decrease in the latter with a d e crease in cystine may indicate the destruction of disulfide bonds in the fiber by proteolytic enzymes of microorganisms. This ultimately leads to the deterioration of the physical properties of such wool, in particular, a decrease in strength by 20.5% (8.3 versus 6.6 cN/tex) and fineness by 7.9% (23.9 versus 22.0 μm). These data provide the opportunity to improve the quality of wool raw materials, but do not reveal the enzymatic mechanisms of the effect of microorganisms on wool fiber, which requires further research.References
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