K. Jernejc
National Institute of Chemistry, Hajdrihova 19, SI-1115 Ljubljana, Slovenia; tel:(+386)(61) 1760200, fax:(+386)(61) 1259244, e-mail: katarina.jernejc@ki.si

ABSTRACT

Lipid synthesis by a citric acid producing Aspergillus niger A-60 strain and a pectolytic strain of Aspergillus niger A-138 carried out under the same cultivation conditions were compared. High production of individual pectolytic enzyme as well as relatively large amounts of citric acid were determined for the pectolytic strain, whereas citric acid producing strain grown in a pectolytic medium excreted two to four times less pectolytic enzymes with relatively low citric acid and two times more lipids present in fungal mycelia. Regarding lipid classes there were less neutral and more glycolipids determined with the pectolytic strain. A higher degree of fatty acid unsaturation with all lipid classes was observed with the citric acid A. niger strain. Both strains cultivated in a pectolytic substrate had similar lipid composition as the citric acid strain cultivated in a citric acid producing medium. On the other hand, citric acid producing strain cultivated in a pectolytic medium and in a citric acid nonaccumulating medium also synthesized a similar lipid pattern. Under conditions of metabolite production there was two times less lipids sinthesized with both A. niger strains examined.