Process engineering for bioflavour production with metabolically active yeasts - a mini-review Magnus Carlquist, Brian Gibson, Yonca Karagul Yuceer, Adamantini Paraskevopoulou, Mari Sandell, Angel I. Angelov, Velitchka Gotcheva, Angel D. Angelov, Marlene Etschmann, Gustavo de Billerbeck, et al. To cite this version: Magnus Carlquist, Brian Gibson, Yonca Karagul Yuceer, Adamantini Paraskevopoulou, Mari Sandell, et al.. Process engineering for bioflavour production with metabolically active yeasts - a mini-review. Yeast, Wiley, 2015, 32 (1), pp.123 - 143. 10.1002/yea.3058. hal-01269072 HAL Id: hal-01269072 https://hal.archives-ouvertes.fr/hal-01269072 Submitted on 28 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Yeast Yeast 2015; 32: 123–143. Published online 16 December 2014 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/yea.3058 Special Issue Article Process engineering for bioflavour production with metabolically active yeasts – a mini-review Magnus Carlquist1, Brian Gibson2, Yonca Karagul Yuceer3, Adamantini Paraskevopoulou4, Mari Sandell5, Angel I. Angelov6, Velitchka Gotcheva6, Angel D. Angelov6, Marlene Etschmann7, Gustavo M. de Billerbeck8,9,10,11 and Gunnar Lidén12* 1Division of Applied Microbiology, Department of Chemistry, Lund University, Sweden 2VTT Technical Research Centre of Finland, Espoo, Finland 3Department of Food Engineering, Faculty of Engineering – Architecture, Canakkale Onsekiz Mart University, Terzioglu Campus, Canakkale, Turkey 4Laboratory of Food Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, Greece 5University of Turku, Functional Foods Forum, Turku, Finland 6Department of Biotechnology, University of Food Technologies, Plovdiv, Bulgaria 7DECHEMA Research Institute, Frankfurt am Main, Germany 8Université de Toulouse, INSA, UPS, INP, LISBP, Toulouse, France 9INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France 10CNRS, UMR5504, Toulouse, France 11INP-ENSAT, Castanet-Tolosan, France 12Department of Chemical Engineering, Lund University, Sweden *Correspondence to: Abstract G. Lidén, Department of Chemical Engineering, Lund University, PO Flavours are biologically active molecules of large commercial interest in the food, fl Box 124, SE-22100 Lund, cosmetics, detergent and pharmaceutical industries. The production of avours can take Sweden. place by either extraction from plant materials, chemical synthesis, biological conversion E-mail: [email protected] of precursor molecules or de novo biosynthesis. The latter alternatives are gaining importance through the rapidly growing fields of systems biology and metabolic engineering, giving efficient production hosts for the so-called ’bioflavours’, which are natural flavour and/or fragrance compounds obtained with cell factories or enzymatic systems. Yeasts are potential production hosts for bioflavours. In this mini-review, we give an overview of bioflavour production in yeasts from the process-engineering perspective. Two specific examples, production of 2-phenylethanol and vanillin, are used to illustrate the process challenges and strategies used. Copyright © 2014 John Wiley & Sons, Ltd. Received: 30 June 2014 Accepted: 1 September 2014 Purpose and scope of this review tongue distinguishing salt, sweet, bitter, sour and umami, and smell, which is detected by sometimes Flavours and fragrances are products of wide- amazingly sensitive receptors in the olfactory sys- spread use in food, detergents, cosmetics and phar- tem in the nose. The chemical diversity in flavour maceuticals. The world market was estimated to be composition is quite large, but in order to generate close to $24 billion in 2013 (www.leffingwell. a smell, the compound must be sufficiently volatile com), so the economic importance of these com- that it can reach the sensory system in the upper pounds is quite significant. part of the nose (Buck and Axel, 1991; Lundström The concept of flavour is complex and involves et al., 2011). Chemical synthesis and extraction most of our senses (Barham et al., 2010). How- from plant cells are the most common procedures ever, the central components most often discussed for producing flavour compounds. Extraction- are taste, which is sensed by receptors on the dependent production has disadvantages, such as Copyright © 2014 John Wiley & Sons, Ltd. 124 M. Carlquist et al. seasonal variation, risk of plant diseases, stability flavour and fragrance compounds via biochemical of the compound and trade restrictions. Chemical pathways. Alternatively, bioconversion of a pre- synthesis, on the other hand, will give compounds cursor in a single-step (or a few steps) enzyme- that, according to EU regulation (EC 1334/2008), catalysed process may also occur. Flavour and will be termed ’flavouring substances’. The term fragrance compounds that can be formed by yeasts ’nature-identical’, which was used in EC Directive include ketones, aldehydes, alcohols, carboxylic 88/388 as a distinction from ’artificial’, no longer acids, esters, lactones and terpenoids (Figure 1). applies. Since consumers typically favour ’natural’ compounds, the price levels are substantially higher for these (Schrader, 2007). The European COST Ac- fl – Flavours as an integrated part of a tion Bio avour (Yeast Flavour Production New fermented product Biocatalysts and Novel Molecular Mechanisms) was initiated to promote the development of biotech- fl nological and eco-efficient production of natural fla- The biological functions of avours in food are vour compounds. This mini-review aims to provide manifold. They may, for example, attract ani- a background to bioflavour production in yeasts from mals to improve seed dispersal and propagation, an applied perspective, including flavour analysis and or warn that the food is spoilt. Flavour com- pounds play an important role in consumer pref- sensory evaluation aspects. Production of two spe- erence and acceptance of food products, and cific flavour compounds, 2-phenylethanol (2-PE) consumers typically prefer natural over synthetic and vanillin, will be used to exemplify process chal- flavour compounds. Odour- and taste-stimulating lenges and possible solutions from a process- components can be classified in the following engineering perspective. groups (Reineccius, 1999): • Volatiles and non-volatiles formed during nor- mal plant metabolism and remaining in the plant The flavour chemistry of yeasts after harvest, e.g. essential oils, fruits and vege- table flavours. Yeasts are microbes with large synthetic capacity • Flavour compounds produced by enzymatic that are able to convert simple carbohydrates and reactions. nitrogen sources into many complex molecules, in- • Flavours developed by microorganisms and fer- cluding many flavour compounds, via enzyme- mentation (wines and dairy products). catalysed reactions. Control of yeast-derived • Flavour compounds resulting from processing flavour compounds as part of fermented beverages (heat treatment, cooking, etc.). has been of interest to producers of beer, wine, Fermentation processes provide wide varieties of sake and other fermented beverages, as long as fl these processes have existed. Tailoring of process avour compounds in, for example, cheese, yogurt, fi kefir, beers, wines, soy sauce, sausages, sauerkraut, conditions to develop speci c organoleptic charac- fi teristics occurred over time through artisanal ob- kimchi and fermented sh products. Flavour may servation and trial-and-error approaches. Latterly, be generated by biochemical reactions of microbial more accurate analytical methods and an improved metabolism or by the activities of residual enzymes understanding of the biochemical mechanisms that after microorganisms have lysed (Reineccius, fl 1999). The use of metabolically active yeasts for determine avour production have enabled more fl fi rapid development of process conditions, via integrated avour production is exempli ed below hypothesis-driven research, to achieve desired fla- by the production of alcoholic beverages, e.g. beer vour characteristics for particular products. A fla- and wine. vour compound can thus be an integrated part of fermented liquors or food, but it can also be a ded- Beverages icated product in itself. Flavour and fragrance compounds can be produced de novo, i.e. simple Yeast is historically linked to the production of sugars and nutrients can be metabolized into fermented beverages. One aspect is, of course, that Copyright © 2014 John Wiley & Sons, Ltd. Yeast 2015; 32: 123–143. DOI: 10.1002/yea Bioflavour production with yeasts – a mini-review 125 Figure 1. Flavour and fragrance compounds produced by yeast de novo from sugars, or via biotransformation of precursors (source: Wang et al., 2011b: 404–407) the fermentations give rise to ethanol in the bever- ethanol and other fusel alcohols is determined not age – thereby preserving it. However, equally im- only by the substrate concentration but also by the portant for the enjoyment of the beverage are the various factors that influence uptake and assimila-