Internal lipids and their fatty acids composition in a sheep wool fiber under biodestruction with fleece microorganisms

Abstract

Microbiological destruction of fibers is a common damage to sheep’s wool. Considering the defining role of internal lipids in the formation of wool fibers surface the aim of the work was to study the structure and lipid composition of the normal and damaged wool. The research was carried out on ewes of the Askanian fine-wool breed. The content of microorganisms was estimated after sowing on dense nutrient environments. Wool fibers surface was studied by scanning electron microscopy, the content of internal lipids by thin layer chromatography after preliminary alkaline hydrolysis of the fiber, and fatty acids composition by gas-liquid chromatography. Biodestructed wool was shown to contain almost three times more bacteria, as well as higher levels of actinomycetes and mushrooms compared to intact wool. The violation of the cuticular layer was detected as the result of the fleece microflora activity. In a defective wool the content of the free internal lipids and non-esterified fatty acids was increased while the content of protein-bound lipids and esterified cholesterol as well as of ceramides was decreased as compared to normal wool. The level of 18-methyleicosanoic acid in the protein-bound lipids of damaged wool was decreased, indicating the destruction of the thioester bonds by which structural lipids are covalently linked to proteins through 18-methyleicosanoic acid. Keywords: 18-methyleicosanoic acid, biodestruction, fatty acids, internal lipids, microorganisms, protein-bound lipids, sheep’s wool fiber