OLEAGINOUS YEASTS FROM EXTREME ENVIRONMENTS IN PATAGONIA AND ANTARCTICA. SCREENING AND ANALYSIS OF LIPID PRODUCTION USING MICRO-BREWERY EFFLUENTS

TROCHINE, ANDREA; CAVALLINI, L.; FAVIER, A.; UTARO, A.; LIBKIND FRATI, D

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Yeasts capable of accumulating more than 20% of their dry weightin lipids are considered oleaginous. These lipids are mainly storedin the form of triacylglycerids (TAGs) in intracellular lipid bodies andmay serve in biodiesel production, animal and human nutrition,among others. Accumulation occurs under nutrient deprivation (e.g.N) in the presence of excess C. Up to date more than 100 speciesof oily yeasts are known, some accumulating up to 70% of their dryweight in lipids. The aim of this work was to obtain information aboutthe ability of a collection of extremophylic or extremotolerant yeaststrains, isolated from Patagonia and Antarctica, to convert into the?obese? phenotype. For this purpose, more than 100 yeast strainswere cultured and analyzed with nile red staining, under both lowand high C/N ratio. Nearly 50 strains showed lipid bodies in mediacontaining excess C and low N. Subsequent analyses of lipidproduction (GMY medium, 5 day culture at 20°C) using gravimetricanalysis showed many of these are oily yeasts, with lipids accumulationsranging from 20 to 65%; and lipid yields from 1 to 4 g lipids/Lculture. The lipid profile of some of these yeasts was analyzed byGC-MS, and showed most are rich in oleic acid (30 to 44%), linoleicacid (15 to 29%), palmitic acid (14 to 24%) and stearic acid (4 to16%). Some include linolenic acid ranging from 2 to 10%. In addition,six strains of the amylase secreting yeast G. pullulans wereanalyzed for growth and lipid production in beer effluents, includingwort runoff and boil remainings. Beer effluents were tested ata density of 5 brix with no other nutrient supplementation. In botheffluents all strains showed biomass and lipid accumulation (10-15g/L biomass and 20-34% lipid on dry weight basis). As a conclusiona number of yeasts show potential for their use in lipid production,including yeasts with potential for consolidated bioprocessing usingstarch containing or starch derived substrates