Synthesis of ethyl acetate from glucose by Kluyveromyces marxianus, Cyberlindnera jadinii and Wickerhamomyces anomalus depending on the induction mode

Abstract

Ethyl acetate is currently produced from fossil carbon resources. This ester could also be microbially synthesized from sugar‐rich wastes of the food industry. Wild‐type strains with GRAS status are preferred for such applications. Production of ethyl acetate by wild‐type yeasts has been repeatedly reported, but comparative studies with several strains at various induction modes are largely missing. Here, synthesis of ethyl acetate by three yeasts with GRAS status, Kluyveromyces marxianus DSM 5422, Cyberlindnera jadinii DSM 2361 and Wickerhamomyces anomalus DSM 6766, was studied under identical and well‐defined conditions in an aerated bioreactor, by inducing the ester synthesis via iron or oxygen limitation. Balancing the ester synthesis was based on measured concentrations of ethyl acetate in the exhaust gas, delivering masses of synthesized ester and synthesis rates in a high temporal resolution. All tested yeasts synthesized ethyl acetate under these conditions, but the intensity varied with the strain and induction mode. The highest yields were achieved under iron limitation with K. marxianus (0.182 g g–1) and under oxygen limitation with W. anomalus (0.053 g g–1). Iron limitation proved to be the better inducer for ester synthesis while oxygen limitation favored ethanol formation. K. marxianus DSM 5422 was the most potent producer of ethyl acetate exhibiting the highest biomass‐specific synthesis rate of 0.5 g g–1h–1 under moderate iron limitation.

Effect of Metabolic Regulators and Aeration on Isocitric Acid Synthesis by Yarrowia lipolytica Grown on Ester-Aldehyde Fraction

“…In addition, a significant amount of acetyl-CoA formed from glucose does not enter the TCA cycle but condenses with ethanol to form ethyl acetate. A similar effect has been also shown for yeast Kluyveromyces marxianus, which produce ethyl acetate in significant quantities under iron-limited conditions [53].…”

Spoilage Potential of Contaminating Yeast Species Kluyveromyces marxianus, Pichia kudriavzevii and Torulaspora delbrueckii during Cold Storage of Skyr

“…Esters composed the second largest group of aroma compounds produced by K. marxianus . Esters are formed by a condensation reaction between alcohols (ethanol or higher alcohols) and acetyl-CoA (for acetate esters) or acyl-CoA (for ethyl esters) [ 55 , 56 ]. It is well known that ester production is positively affected by precursor availability, i.e., the alcohols released by K. marxianus in this study, and the presence of lactose in skyr required for acetyl-CoA formation [ 43 , 57 ].…”

“…In this study, ethyl acetate (solvent aroma), ethyl butyrate (pineapple), ethyl hexanoate (aniseed, apple), ethyl octanoate (sour apple) and isoamylacetate (banana, pineapple) were produced in large quantities, close to or higher than the thresholds. The ability of K. marxianus strains to produce esters, in particular ethyl acetate, has been frequently reported [ 38 , 56 , 59 , 60 ]. Previously, Leclercq-Perlat et al identified similar aroma compounds produced by K. marxianus in a cheese medium (e.g., hexanal, 2 (3)-methylbutanal, butanol, 2 (3)-methylbutanol, 2-methylpropanol) and reported a link between the levels of isoamylacetate and ethyl acetate, and ester-like fruity odours [ 61 ].…”

Selection of Producer of α-Ketoglutaric Acid from Ethanol-Containing Wastes and Impact of Cultivation Conditions

“…In media with an iron shortage, microbial growth is limited by available energy resources in the cell [47]. Under iron deficiency, the conversion of organic substance falls; most acetyl-CoA does not enter the TCA cycle and is condensed with the formation of ethyl acetate [48]. As shown in the work [49], the increase in iron concentration in cultivation media activates the TCA cycle, respiratory chain and oxidative phosphorylation in Y. lipolytica.…”