Oleaginous yeasts from extreme environments in Patagonia and Antarctica. Screening and analysis of lipid production using micro-brewery effluents.

CAVALLINI L.; LIBKIND D.; TROCHINE A.; UTTARO AD.; FAVIER A.

Buenos Aires

Congreso; LIII Reunión anual de la SAIB; 2017

SAIC, SAIB, SAI, SAA, SAB, SAFE, SAFIS, SAH, SAP

OLEAGINOUS YEASTS FROM EXTREME ENVIRONMENTS IN PATAGONIA AND ANTARCTICA. SCREENING AND ANALYSIS OF LIPID PRODUCTION USING MICRO-BREWERY EFFLUENTSYeasts capable of accumulating more than 20% of their dry weight in lipids are considered oleaginous. These lipids are mainly stored in the form of triacylglycerids (TAGs) in intracellular lipid bodies and may 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 species of oily yeasts are known, some accumulating up to 70% of their dry weight in lipids. The aim of this work was to obtain information about the ability of a collection of extremophylic or extremotolerant yeast strains, isolated from Patagonia and Antarctica, to convert into the ?obese? phenotype. For this purpose, more than 100 yeast strains were cultured and analyzed with nile red staining, under both low and high C/N ratio. Nearly 50 strains showed lipid bodies in media containing excess C and low N. Subsequent analyses of lipid production (GMY medium, 5 day culture at 20°C) using gravimetric analysis showed many of these are oily yeasts, with lipids accumulations ranging from 20 to 65%; and lipid yields from 1 to 4 g lipids/L culture. The lipid profile of some of these yeasts was analyzed by GC-MS, and showed most are rich in oleic acid (30 to 44%), linoleic acid (15 to 29%), palmitic acid (14 to 24%) and stearic acid (4 to 16%). Some include linolenic acid ranging from 2 to 10%. In addition, six strains of the amylase secreting yeast G. pullulans were analyzed for growth and lipid production in beer effluents, including wort runoff and boil remainings. Beer effluents were tested at a density of 5 brix with no other nutrient supplementation. In both effluents all strains showed biomass and lipid accumulation (10-15 g/L biomass and 20-34% lipid on dry weight basis). As a conclusion a number of yeasts show potential for their use in lipid production, including yeasts with potential for consolidated bioprocessing using starch containing or starch derived substrates.Keywords: yeasts, oleaginous, lipids, brewery effluents