Effect of essential oil of Citrus cinensis cv new hall – Citrus aurantium (indigenous in Greece) upon growth of Yarrowia lipolytica

Abstract

The effect of essential oil from Citrus cinensis cv new hall – Citrus aurantium (indigenous in Greece) upon growth of the dimorphic non-conventional yeast Yarrowia lipolytica strain ACA-DC 50109 was studied. The microorganism was aerobically cultivated in batch mode in carbon-limited media. The essential oil was added into the culture medium in different quantities while the control experiment was carried out without addition. The essential oil caused a relatively important decrease of the highest concentration of biomass produced. Additionally, biomass yield on glucose consumed was significantly decreased with the addition of the oil on the cultivation medium. Moreover, the addition of the essential oil considerably increased the lag time of the culture. In all trials, a remarkable drop the pH value of the medium was observed due to the biosynthesis of small amounts of organic acids. Given that one principal component of this membrane is the one of cellular lipids, it was assumed that the extraction and the analysis of cellular lipids could provide information about the microbial behaviour. Total lipids were extracted, methanolyzed and analyzed with the aid of G.L.C. In the control experiment, the culture conditions did not favour accumulation of storage lipid inside the yeast cells and, hence, lipid produced corresponded to 5–9% (wt/wt) in dry cell mass. Similar concentrations of cellular lipids were produced when essential oil was added in various amounts. When essential oils were added, an increase of lower aliphatic chain saturated fatty acids was observed, suggesting an alteration in the membrane function.