Degradation of Sterols, Triacylglycerol, and Phospholipids by Soil Microorganisms

Abstract

Cholesterol, β-sitosterol, triolein, and a mixture of phospholipids were added to aliquots of garden soil and recovered by extraction after 11, 17, and 23 weeks. Degradation of these lipids occurred in fresh aliquots of soil but not in those that had been sterilized by autoclaving. The half-life times of the different lipid compounds in soil comprised about 4 to 6 months. In response to the treatment of soil with lipids, both the numbers and the identities of bacteria and fungi therein changed dramatically. We isolated and identified several microorganisms, including one mesophilic Streptomyces sp., two thermophilic Bacillus spp., and two thermophilic Mycobacterium spp., as well as seven species of fungi belonging to the genera Penicillium, Aspergillus , and Cladosporium , that all were able to utilize lipids as sole sources of carbon in their nutrition. Cholesterin, β-Sitosterin, Triolein und ein Gemisch von Phospholipiden wurden jeweils Gartenerde zugegeben und nach 11, 17 und 23 Wochen wieder extrahiert. Zersetzung dieser Lipide erfolgte in frischer, jedoch nicht in vorher autoklavierter Erde. Die Halbwertzeiten der verschiedenen Verbindungen betrugen 4 – 6 Monate. Nach Zugabe der Lipide variierten die Bakterien und Pilze in der Gartenerde quantitativ und qualitativ. Eine mesophile Streptomyces -Art, zwei thefmophile Bacillus-Arten, zwei thermophile Mycobacterium -Arten und sieben Arten von Pilzen der Gattungen Penicillium, Aspergillus und Cladosporium , die in der Lage waren, Lipide als alleinige Kohlenstoff quelle zu verwerten, wurden identifiziert.