Untitled

Abstract

Cell growth, lipid accumulation and cellular lipid composition of Yarrowia lipolytica growing on mixtures of industrial fats containing stearic, oleic, linoleic and palmitic acid have been studied. During growth, the strain incorporated oleic and linoleic acids more rapidly than the saturated fatty acids. Relatively high lipid accumulation (up to 0.44 g of lipids per g of dry matter) was observed when stearic acid was included in the culture medium. In contrast, substrates rich in oleic acid did not favor cellular lipid accumulation. The accumulated lipids, mainly composed of triacylglycerols (45-55% w/w), demonstrated a different total fatty acid composition compared with that of the substrate; in all cases, the microorganism showed the unusual capacity to increase its cellular stearic acid level, even if this fatty acid was not found in high concentrations in the substrate. This permitted the synthesis of interesting lipid profiles with high percentages of stearic acid and non-negligible percentages of palmitic and oleic acid, with a composition resembling that of cocoa-butter.

Cocoa-Butter-Equivalent Production from <i>Yarrowia lipolytica</i> by Optimization of Fermentation Technology

“…Hence, the main problem to solve is how to increase the level of total saturated fatty acids inside the yeast cells specially the content of C18:0 (Lipp and Anklam, 1998;Papanikolaou and Aggelis, 2010;Ratledge and Wynn, 2002). Numerous strategies have been explored to the increase of Saturated Fatty Acids (SFA), such as the genetic manipulation of oleaginous yeast (Ykema, 1989), inhibition of ∆ 9 and ∆ 12 dehydrogenase (Moreton, 1985), cultivation of yeasts on low-oxygenated media (Davies et al, 1990) and addition of stearic acid or derivative into the medium (Papanikolaou et al, 2001).…”

Conversion of Mutton Fat to Cocoa Butter Equivalent by Increasing the Unsaturated Fatty Acids at the Sn-2 Position of Triacylglycerol Through Fermentation by <i>Yarrowia Lipolytica</i>

“…Oleaginous yeasts, which are considered as ideal candidates for this application of the synthesis of microbial substitutes of CB (Ratledge and Wynn, 2002;Papanikolaou and Aggelis, 2010), have been utilized by many investigators due to the fact that these microorganisms reserve their lipids mostly in the form of TAGs esterified in the Sn-2 position by UFAs (Padley, 1994). Papanikolaou et al (2003) used stearin (an industrial derivative of animal fat composed of 100% free fatty acids), glycerol and glucose as co-substrates (Papanikolaou et al, 2003) or stearin and hydrolyzed rapeseed oil as co-substrates (Papanikolaou et al, 2001) for Y. lipolytica LGAM S(7)1 to synthesize a cocoa butter substitute, which contained large amount of stearic acid (from 40 to 80%, w/w). However, some research teams conducting the production of CBE by fermentation processing faced exactly the opposite problem (Moreton, 1985;Ykema et al, 1989;Gierhart, 1984;Roux et al, 1995), that is how to enhance stearic acid content, which is generally low in the oleaginous microorganisms and numerous methods have been used to achieve this target, such as inhibition of ∆9 and ∆12 desaturase (Moreton, 1985), genetic manipulation of oleaginous yeast (Ykema et al, 1989), addition of SFAs or derivative into the medium (Gierhart, 1984) and cultivation of yeasts on low oxygenation medium (Roux et al, 1995).…”

“…The information about the biochemical behavior of these microorganisms growing on fats is not very clear and also fat depletion from the growth media (Aggelis and Sourdis, 1997), the degradation of the storage lipids and the microbial fatty acid specificity (Papanikolaou et al, 2001), are not studied in details. Moreover, animal fat was generally added to the medium as substrate after being hydrolyzed to free fatty acids (Papanikolaou et al, 2003;Papanikolaou et al, 2001) instead of intact triglycerides owing to its lack of extracellular lipase of these microorganisms.…”

An Effective Method of Continuous Production of Erythritol from Glycerol by Yarrowia lipolytica MK1

“…Oleic acid was described as the main monounsaturated fatt y (36). In turn, using industrial fats in the process with yeast resulted in a different total fatt y acid composition, which was characterised by a high concentration of cellular stearic acid (37).…”