ANTARCTIC FUNGI: A BIO-SOURCE ALTERNATIVE TO PRODUCE POLYUNSATURATED FATTY ACIDS (PUFAs)

Abstract

The Antarctic ecosystem is a combination of conditions including extremely low values of temperature. The environmental temperature is one of the parameters thoroughly affecting the structure and composition of fungal membranes lipids. The psychrophilic fungi generally increase the disorder within macromolecules to maintain membrane fluidity at low temperatures. The strategy adopted by Antarctic fungi is to increase the proportion of unsaturated fatty acid that allows maintaining a semi-fluid state of the membranes. This ecological feature might be exploited for using Antarctic fungi as potential alternative source of polyunsaturated fatty acids (PUFAs) for human diet. This study provides both the characterization of fungal strains isolated from Antarctica by lipidomic analysis and the laboratory/large-scale production of fungal biomass with high content of beneficial PUFAs. In detail, three fungal species isolated from environmental matrices from Antarctica were tested and identified at genome level. Growth experiments to evaluate the influence of temperature and substrate in the yield in biomass and unsaturated fatty acid (UFA) were conducted. The results showed that the selected fungi have a high percentage of UFA compared to saturated ones; low growth temperatures increase the yield in linolenic fatty acid (C18:3); the biomass yield depends on the composition of the growth substrate and a satisfying qualitative-quantitative yield has also been obtained by using an agri-food chain waste product as growth substrate. IMPORTANCEThe presence of polyunsaturated fatty acids (PUFAs) in human and animal diet is gaining attention because PUFAs have several recognized functional properties: they modulate immune response, have anti-allergic and anti-inflammatory activity, cardio-protective effect and reduce blood LDL cholesterol levels. Human diets typically do not contain sufficient PUFAs because foods rich in PUFAs are few and it is therefore necessary to supplement this diet. Food supplements with these types of fatty acid currently commercially available come from marine fish oils and this source is no longer sustainable. It is necessary to develop efficient industrial processes capable of producing good quality PUFAs and in quantity, even using as carbon and nitrogen sources agro-industrial chains (in our case spent yeast from brewing and whey waste) waste products. Like microorganisms we used Antarctic fungi because they are adapted at very low temperature increasing the proportion of unsaturated fatty acid that allows maintaining a semi-fluid state of the membranes.