Bioreduction of α,β-unsaturated ketones and aldehydes by non-conventional yeast (NCY) whole-cells

Production and characterization of aroma compounds from apple pomace by solid-state fermentation with selected yeasts

“…From the technological point of view, it should be noted that during the period of 21e28 days of fermentation, the levels of the quantified unsaturated carbonyl compounds decreased (p < 0.01) in fermentations with both Hanseniaspora strains, sometimes up to 60% (Table 5). This decrease may be associated with the presence of carbonyl reductases, reported in species of the genus Hanseniaspora (Goretti et al, 2011).…”

Non-Conventional Yeasts as Sources of Ene-Reductases for the Bioreduction of Chalcones

“…It is worth noting that in any case, the screened NCYs did not exhibit any reduction of the C=O bond (Figure 2). In a previous study, we observed that many of the yeasts herein screened possess carbonyl reductase activity (alcohol dehydrogenase, ADH), being able to reduce the carbonyl group of molecules such as ketoisophorone [40]. The high chemoselectivity in the bioreduction of chalcones observed in the present study is probably not due to the lack of ADH activity in the yeast strains, rather to the steric hindrance given by the bulky phenyl substituents or to enzyme localization (not accessible to the substrates).…”

“…Thirteen NCY strains belonging to ascomycetous and basidiomycetous species (genera Candida, Cyberlindnera, Goffeauzyma, Hanseniaspora, Kazachstania, Naganishia, Pichia, Scheffersomyces, Solicoccozyma and Wickerhamomyces) were used. They were preliminarily selected from a few hundred of environmental strains isolated worldwide for their ability to catalyze the biotransformation of α,βunsaturated alkenes [39][40][41]. All strains are conserved at the Industrial Yeasts Collection DBVPG of The following microbiological culture media were used: YEPG: yeast extract 10 g L −1 , peptone 10 g L −1 , glucose 20 g L −1 and agar 15 g L −1 ; and Carvone Medium (CM) [39]: yeast extract 3 g L −1 , malt extract 3 g L −1 , peptone 5 g L −1 , glucose 10 g L −1 and pH 6.5.…”

“…Lyophilized NCYs whole-cells were obtained as previously reported [40]. Briefly, aliquots (200 µL) of 24 h cell suspensions, calibrated to A 580 = 0.5 (approx.…”

“…Recent studies revealed that Non-Conventional Yeasts (NCYs) are able to express a number of promising biotechnological properties [35][36][37], including the ability to express important ERs activities. In this framework, due to the presence of cofactor-recycling systems for NAD(P)H at the level of cell metabolism, biotransformation processes catalyzed by whole-cells of NCYs could be considered as useful and cheaper alternatives in place of using purified enzymes for reducing α,β-unsaturated alkenes including chalcones [38][39][40][41][42].…”