unsaturated fatty acid mutant of Aspergillus niger with partially defective Δ9-desaturase

• Published in: Canadian journal of microbiology Vol. 31; no. 4; pp. 346 - 351
• Main Authors: Chattopadhyay, Panchanon, Banerjee, Santu Kumar, Sen, Kalyani, Chakrabarti, Parul
• Format: Journal Article
• Language: English
• Published: NRC Research Press 01.04.1985
• Subjects: Aspergillus niger; auxotrophs; conidia; detergents; microsomes; monounsaturated fatty acids; mutagenicity; saturated fatty acids; stearoyl-CoA desaturase
• ISSN: 1480-3275; 1480-3275
• DOI: 10.1139/m85-066

The wild-type Aspergillus niger (V₃₅) does not require fatty acids for growth. Four unsaturated fatty acid auxotrophs designated as UFA₁, UFA₂, UFA₃, and UFA₄ have been produced from this organism by treating the conidia of the wild-type strain with a mutagen, N-methyl-N′-nitro-N-nitrosoguanidine, followed by isolation on media containing monounsaturated fatty acids and the nonionic detergent, Brij 58. Optimal growth of the mutants comparable with that of the wild type was achieved with medium supplemented with C₁₆ or C₁₈ unsaturated fatty acids containing at least one cis double bond at the Δ⁹ position. Some other fatty acids (18:1 Δ¹¹cis and 16:1 Δ⁹trans) support growth to some extent. The mutants do not grow at all in the presence of saturated fatty acids. Fatty acid analyses of the mutant, UFA₂, grown in the presence of different fatty acid supplements reveal that it may be defective in a desaturase system. Experiments with unlabeled and [1-¹⁴C]palmitoyl-CoA have shown that the microsomes of the mutant (UFA₂) contain a partially defective Δ⁹-desaturase system.