A high throughput screening (HTS) methodology for evaluation of cellular lipid content based on Nile red fluorescence reads using black background 96-wells test plates and a plate reader equipment allowed the rapid intracellular lipid estimation of strains from a Brazilian phylloplane yeast collection. A new oleaginous yeast, Meyerozyma guilliermondii BI281A, was selected, for which the gravimetric determination of total lipids relative to dry weight was 52.38% for glucose or 34.97% for pure glycerol. The lipid production was optimized obtaining 108 mg/L of neutral lipids using pure glycerol as carbon source, and the strain proved capable of accumulating oil using raw glycerol from a biodiesel refinery. The lipid profile showed monounsaturated fatty acids (MUFA) varying between 56 or 74% in pure or raw glycerol, respectively. M. guilliermondii BI281A bears potential as a new biodiesel feedstock.

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We studied the biotechnological potential of the recently isolated yeast Meyerozyma guilliermondii BI281A to produce polyunsaturated fatty acids and ethanol, comparing products yields using glucose, raw glycerol from biodiesel synthesis, or whey permeate as substrates. The yeast metabolism was evaluated for different C/N ratios (100:1 and 50:1). Results found that M. guilliermondii BI281A was able to assimilate all tested substrates, and the most efficient conversion obtained was observed using raw glycerol as carbon source (C/N ratio 50:1), concerning biomass formation (5.67 g·L−1) and lipid production (1.04 g·L−1), representing 18% of dry cell weight. Bioreactors experiments under pH and aeration‐controlled conditions were conducted. Obtained fatty acids were composed of ~67% of unsaturated fatty acids, distributed as palmitoleic acid (C16:1, 9.4%), oleic acid (C18:1, 47.2%), linoleic acid (C18:2 n−6, 9.6%), and linolenic acid (C18:3 n−3, 1.3%). Showing fermentative metabolism, which is unusual for oleaginous yeasts, M. guilliermondii produced 13.7 g·L−1 of ethanol (yields of 0.27) when growing on glucose medium. These results suggest the promising use of this uncommonly studied yeast to produce unsaturated fatty acids and ethanol using cheap agro‐industrial residues as substrates in bioprocess.

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