Sumner, J L (1968) Studies on thermophilic fungi with particular reference to their nitrogen nutrition and lipid composition. Doctoral thesis, Keele University.

[img]
Preview
Text
SumnerPhD1968.pdf

Download (21MB) | Preview

Abstract

Two aspects of the physiology of thermophilic fungi
have been investigated, their nitrogen nutrition and lipid composition. The main experimental material was the phycomycete fungus Mucor pusillus.
Preliminary experiments indicated that M. pusillus
grew and spored well in still culture at 45-50°, on a synthetic medium containing a nitrogen source at a concentration of 250mg. N/1. and a carbon source at 20g./l. These culture conditions were used in a study of the effect of different nitrogen sources on the growth and sporulation of this fungus. Nutritionally, M. pusillus proved extremely versatile, being able to grow and spore on a wide range of inorganic and organic nitrogen sources.
The fatty acid composition of the mycelial lipids of psychrophilic, mesophilic, thermotolerant and thermophilic fungi in the Mucorales was studied by gas-liquid chromatography (GLC), while the individual fatty acids were identified by combined mass spectrometry and gas chromatography. The lipids of thermophilic and thermotolerant fungi were found to be more saturated than those of psychrophilic and mesophilic fungi.
The effect of various environmental factors on the fatty
acid composition of the lipids of M. pusil1us were also studied by GLC. The mycelial lipids were found to be more unsaturated when the fungus was grown at a lower temperature, or when the nitrogen content of the medium was increased; increasing the carbon concentration of the medium resulted in increased synthesis of mycelial lipids. Electrometric determination of the oxygen
partial pressure (p02) in the medium of cultures of M. pusillus showed that at 50 the fungus grew under almost completely anaerobic conditions, and the possibility that the oxygen concentration may limit the biosynthesis of unsaturated fatty acids was investigated. Increasing the oxygen concentration of the gas phase above growing surface cultures resulted in only small increases in the degree of lipid unsaturation, and it is considered that significant increases in lipid unsaturation would require highly aerated submerged culture conditions.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Natural Sciences > School of Life Sciences
Depositing User: Lisa Bailey
Date Deposited: 01 Feb 2019 15:14
Last Modified: 01 Feb 2019 15:14
URI: http://eprints.keele.ac.uk/id/eprint/5746

Actions (login required)

View Item View Item