Studies on Upgradation of Waste Fish Oil to Lipid-Rich Yeast Biomass in Yarrowia lipolytica Batch Cultures

Abstract

The aim of the study was to evaluate the possibility to utilize a fish waste oil issued from the industrial smoking process in nitrogen-limited Yarrowia lipolytica yeast batch cultures. The waste carbon source was utilized by the yeast and stimulated the single cell oil production via an ex novo pathway. The yeast biomass contained lipids up to 0.227 g/gd.m.. Independently from culture conditions, high contents of very long chain fatty acids were quantified in yeast biomass including docosahexaenoic (DHA), eicosapentaenoic acid (EPA), eicosenic and erucic acids. The pH regulation did not influence the cellular lipids yield (0.234 g/gd.m.). Meanwhile, the intensification of the oxygenation of medium by changing the mixing speed (maximum concentration of lipids produced 4.64 g/dm3) and decreasing the amount of inoculum had a positive effect on the culture parameters in waste fish oil medium. Further work on upgradation of the original waste is advisable, especially because the oil indicated high content of polyphenols and lower susceptibility to oxidation than microbial oil derived from control olive oil medium.

Use of Non-Conventional Yeast Yarrowia lipolytica in Treatment or Upgradation of Hydrophobic Industry Wastes

“…Approximately 90% of the waste fish oil in the medium was used, and the obtained biomass served as a biocatalyst in the esterification of phenolic compounds with antimicrobial and/or antioxidant activities. Moreover, Fabiszewska et al [5] provided evidence for high nutritional value of the microbial oil obtained in Y. lipolytica KKP 379 yeast culture in waste fish oil medium resulting from the high content of unsaturated fatty acids including DHA and EPA and high polyphenols concentration, what makes the lipid-rich yeast biomass a promising source of beneficious nutrients.…”

“…γ-decalactone [19], carotenoidse.g. β-carotene [20], organic acids-α-ketoglutaric, succinic, citric and pyruvic acids [21], lipases-enzymes used in food production, for water purification or as an ingredient in detergents [22], SCP (Single Cell Protein)-proteins of microbiological origin that can be used as feed additives [23], SCO (Single Cell Oil)-microbiological oil which is a source of essential unsaturated fatty acids (EFA) with valuable properties for both humans and farm animals [5,24].…”

“…Hydrophobic industrial wastes are mainly a carbon source for cells. There is widespread confidence that yeasts utilize lipids from the substrate for energy purposes via the fatty acid β-oxidation process [5]. Waste disposal with the simultaneous synthesis of added value products is a double benefit of this approach.…”

Strategies for increasing lipid accumulation and recovery fromY. lipolytica: A review

“…Therefore, many studies have investigated the potential use of this yeast for the valorization of waste and by-products. Animal fats such as tallow (Papanikolaou et al, 2007) and pork fat (Patrignani et al, 2011), vegetable (Louhasakul et al, 2020), cooking (Lopes et al, 2019) and fish (Fabiszewska et al, 2021) oils waste have been used as substrates by Y. lipolytica to produce single cell oil via ex novo pathway. However, some hydrophobic substrates may be toxic to the cells according to their chain length.…”

“…When tallow, rich in saturated fatty acids, was used as a carbon source, the oil produced by Y. lipolytica was characterized by a high content in saturated FAs (78% of C18:0 and 17% of C16:0) and only small amounts of unsaturated FA (5% of D9 C18:1) (Papanikolaou et al, 2007). Likewise, when fish oil was used as carbon source, the content of lipids accumulated in the cells was comparable to the substrate and was characterized by the presence of very long chain FAs (Fabiszewska et al, 2021). Similarly, when stearin and hydrolyzed oleic rapeseed oil were used as carbon sources, saturated FAs were the most prevalent and their percentage proportionally increased with that of stearin.…”