Study of lipids from a forest soil

in the Tangier area (north of Morocco)

 

A. Aassiri1, L. Lemée2, M. Khaddor1*, A. Amblès2

1 Laboratoire de Physico-Chimie des Matériaux, Substances Naturelles et Environnement,

Faculté des Sciences et Techniques, 90000,Tanger, Maroc

2 Laboratoire de Synthèse et Réactivité des Substances Naturelles, Faculté des Sciences, 82022 Poitiers , France

* Corresponding author. E-mail: mkhaddor@hotmail.com

Received: 22 February 2007; revised version accepted: 18 July 2007

 

Abstract

     The extractible organic matter of a forest soil from Tangier area (north of Morocco) which represents 2% of the total organic matter (TOM) was fractionated and characterised using gas chromatography coupled with mass spectrometry (GC/MS). The main lipidic components are hydrocarbons, fatty acids, fatty acids methyl esters and alcohols. The n-alkanes distribution dominated by long odd members (C21 to C35) is characteristic of a plant input. Long even carbon numbered n-alcohols (C14 to C32) also originates from higher plants. However the relatively high amount of long odd compounds indicates that alkanols partly originate from the biological reduction of acids. The exclusive presence of stanols which originate from hydrogenation of phytosterols is in agreement with the point. Fatty acids (C14-C34) and native methyl esters (C14-C32) present different distributions traducing different origins. Indeed fatty acids are mainly of plant origin whereas methyl esters testify of a high bacterial activity. Finally organic matter from the studied soil is mainly of plant origin but traduces a high microbial activity. Moreover the unusual observed distributions when compared to studied French soils associated with the low amount of total lipids confirms the strong turn-over of this pool probably due to the relatively high temperature.

 

Keywords: Forest soil; Extraction; Lipids; GC/MS.

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