Synthesis of Industrially Useful Phenolic Compounds Esters by Means of Biocatalysts Obtained Along with Waste Fish Oil Utilization

Bartłomiej Zieniuk,Małgorzata Wołoszynowska,Ewa Białecka-Florjańczyk,Agata Fabiszewska

doi:10.3390/su12145804

Abstract

The purpose of the study was to utilize the waste fish oil after fish smoking process in Y. lipolytica yeast batch cultures in order to assess its valorization to whole-cell biocatalysts with lipolytic properties. Almost 90% of the waste carbon source in medium was used and batch cultures of Y. lipolytica W29 were characterized with biomass yield of 18.59 g/dm3 and lipolytic activity of 53.41 U/g. The yeast biomass was used as a whole-cell biocatalyst in the synthesis of esters of selected phenolic compounds (acetates of 2-phenylethanol, tyrosol (2-(4-hydroxyphenyl) ethanol) and 3-phenyl-1-propanol, and ethyl esters of phenylacetic, 4-hydroxyphenylacetic, 3-phenylpropanoic, and 3-(4-hydroxyphenyl) propanoic acids). Y. lipolytica biomass was able to catalyze esterification of 3-phenylpropanoic acid (conversion of 95% after 24 h), but conversion of other acids to their esters was very weak, and in the case of transesterification of aromatic alcohols with vinyl acetate, conversions were 27%–63% after 24 h. Synthesized esters were tested prior potential activities as food additives. Esters of hydroxylated phenolic compounds showed activity of 2.5 mg/mL against Klebsiella pneumoniae and Citrobacter freundii, exhibited similar antioxidant properties to their precursors, and were better soluble in lipids, which increases the possibility of their use in the food industry.

Highlights

Fish meat is a valuable food product, being a source of long-chain polyunsaturated fatty acids, as well as proteins rich in essential amino acids and vitamins A, D, and E
Four strains of Y. lipolytica were compared for growth and production of intracInellpurlealrimlipinoalyryticsteundziyems,efsouinr astrmaeindsiuomf Yc.olinptoaliyntiincagwwearsetecofimshpoairleadsfaormgarionwctahrbaonndsporuordcuec(tFioignuoref i1n).tracellular lipolytic enzymes in a medium containing waste fish oil as a main carbon source (Figure 1)
It was proven that a waste fish oil could be a very good substrate for the production of Y. lipolytica yeast biomass with catalytic properties

Summary

Introduction

Fish meat is a valuable food product, being a source of long-chain polyunsaturated fatty acids, as well as proteins rich in essential amino acids and vitamins A, D, and E. The content of these chemical compounds is varied and depends on different factors, such as the species of fish, its age, or the type of food consumed [1,2]. Fats and oils that left the sewage plant after an incomplete wastewater treatment process can form a thin layer on the surface of water reservoirs, leading to a reduction in gas exchange, and after getting into the soil fats can block the pores and reduce microflora activity [9]

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