Lipid and Poly‐Unsaturated Fatty Acid Production by Oleaginous Microorganisms Cultivated on Hydrophobic Substrates

Exploring the Impact of Solid-State Fermentation on Macronutrient Profile and Digestibility in Chia (Salvia hispanica) and Sesame (Sesamum Indicum) Seeds

“…These authors related the excess of lipids in the substrate to their use by the microorganism to produce more phospholipids, which are generally rich in unsaturated fatty acids. Moreover, Tzirita, Quilty & Papanikolaou (2020) note that the oleaginous microorganisms, which are able to use lipids as substrates, may produce de novo lipidic species with a polyunsaturated profile [21]. Overall, the results of the present study relate to an increase especially in linoleic acid, which could likely be related to the fact that this fatty acid represents around 60-75% of the fat fraction of the fungus [20].…”

“…In addition, in the presence of a fat-rich substrate as chia and sesame, another possible explanation for increased total lipid content could be related to the de novo synthesis and accumulation of lipidic species. This is a documented phenomenon occurring when oleaginous microorganisms are able to utilize lipids in hydrophobic and lipid-rich substrates [21]. When looking into the lipidic species (Figure 2a), as expected, the control chia and sesame flours were composed solely of triglycerides with residual proportions of the other species, but fermentation accounted for the conversion of approximately 5% of the triglycerides into 1,3 and 1,2-diglycerides and fatty acids.…”

Insights into hydrophobic waste valorization for the production of value‐added oleochemicals

“…In the case of ex‐novo synthesis, hydrophobic substrates are first converted to free fatty acids through various microbial lipolytic mechanisms, followed by active transportation inside the microbial cells (Papanikolaou & Aggelis, 2011 ). The availability of only hydrophobic substrates to the microorganism in an external medium makes the process growth‐oriented and does not require nitrogen limitations (Tzirita et al, 2020 ).…”

“…In general, heterotrophic oleaginous microorganisms that are capable of growing on a hydrophobic substrate and producing lipases will consume the substrate in three major steps; (1) emulsification (contact between the substrate and cells via surfactant or liposan emulsifier production) or adhesion of cells to hydrophobic substrate droplets, (2) Hydrolysis by expression of lipolytic enzymes and (3) Uptake of the free fatty acids using active transport inside the cells (Fickers et al, 2005 ; Thevenieau et al, 2018 ; Tzirita et al, 2020 ). The length of the carbon chain as well as the degree of unsaturation influence fatty acid transport into cells (Thevenieau et al, 2018 ).…”

“…When fatty acids are available in the growth medium, the de‐novo pathway is blocked by the inhibition of important enzymes such as fatty acid synthase (FAS) and ATP‐Citrate lyase (ACL) (Papanikolaou & Aggelis, 2011 ; Tzirita et al, 2020 ). Oleochemicals such as DHA are synthesized via de‐novo synthesis and therefore it is challenging to select a microorganism that is capable of simultaneous de‐novo and ex‐novo synthesis.…”