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

Agata Urszula Fabiszewska,Mariola Kozłowska,Patrycja Maria Mazurczak-Zieniuk,Małgorzata Wołoszynowska,Paulina Misiukiewicz-Stępień,Dorota Nowak,Bartłomiej Zieniuk

doi:10.3390/foods10020436

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/g d.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/g d.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.

Highlights

The decrease in the content of microbial oil in cells may be caused by its partial consumption and use for energy purposes by β-oxidation of fatty acids [20]
The nutritional value of the microbial oil obtained in Y. lipolytica yeast culture in waste fish oil medium resulting from the high content of unsaturated fatty acids including
DHA and eicosapentaenoic acid (EPA) and high polyphenols concentration, makes the lipid-rich yeast biomass a promising source of beneficious nutrients

Summary

Introduction

Fish consumption and seafood popularity have been growing because of the undeniably benefit to human health. Fish wastes are predicted to arise worldwide and they stand for one of the continuously gaining grounds for waste management fields [1,2]. There has been a constant increase in the exploitation of fish resources and the estimated quantity used for human consumption is 105.6 million tons (75% of the worldwide fish production). The remaining 25% (34.8 million tons) are considered as wastes. Solid waste represents 20–60% of the initial raw material [3]. Two conventional methods of waste utilization have been used nowadays. The wastes are being reused as either animal feed (composting, ensilation and fermentation of waste) or as a fertilizer [2]. Bioremediation and biostimulation are biotechnological strategies that eliminate environmental pollutants along with growth stimulation of indigenous microorganisms [4]

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Conclusion