Bioproduction of 2-Phenylethanol through Yeast Fermentation on Synthetic Media and on Agro-Industrial Waste and By-Products: A Review

Abstract

Due to its pleasant rosy scent, the aromatic alcohol 2-phenylethanol (2-PE) has a huge market demand. Since this valuable compound is used in food, cosmetics and pharmaceuticals, consumers and safety regulations tend to prefer natural methods for its production rather than the synthetic ones. Natural 2-PE can be either produced through the extraction of essential oils from various flowers, including roses, hyacinths and jasmine, or through biotechnological routes. In fact, the rarity of natural 2-PE in flowers has led to the inability to satisfy the large market demand and to a high selling price. Hence, there is a need to develop a more efficient, economic, and environmentally friendly biotechnological approach as an alternative to the conventional industrial one. The most promising method is through microbial fermentation, particularly using yeasts. Numerous yeasts have the ability to produce 2-PE using l-Phe as precursor. Some agro-industrial waste and by-products have the particularity of a high nutritional value, making them suitable media for microbial growth, including the production of 2-PE through yeast fermentation. This review summarizes the biotechnological production of 2-PE through the fermentation of different yeasts on synthetic media and on various agro-industrial waste and by-products.

Optimization of 2-Phenylethanol Production from Sweet Whey Fermentation Using Kluyveromyces marxianus

“…Optimizing the use of waste in the raw state (undiluted), to produce value-added metabolites, has operational and economic advantages. At an operational level, it allows lower operating volumes and, as observed in this study, it contributes to the remediation of sweet whey, with which a significant economic benefit could be obtained [6].…”

“…As pointed out in the introduction, few studies explore the use of industrial waste to produce aromatic compounds, especially using them crude, that is, undiluted. The review carried out by [6] presents an analysis of the investigations that have used agro-industrial residues. Like the grape must, where the production of 2-PhEtOH was 0.39 g/L with 3 g/L of precursor in 84 h of culture.…”

“…Since the production by chemical synthesis (Friedel-Crafts and Gringnard) and plant extraction, generates corrosive and toxic waste for humans and the environment [1-4] and makes difficult the use of aroma in the food industry where aroma legally labeled "natural" are required [5]. 2-Phenylethanol (2-PhEtOH) is a higher alcohol with a pleasant rosy aroma, whose demand increases between 10 and 15% each year and when it comes from natural sources, its market value may be higher than USD 1000 dollars/kg [6]. It is important to note that its production is limited due to adverse effects linked to chemical synthesis, which makes it attractive to obtain by fermentation [7].…”

Multi-Strain and -Species Investigation of Volatile Metabolites Emitted from Planktonic and Biofilm Candida Cultures

“…Ethanol is typically derived from glucose metabolism and fermentation, while 1-butanol, 3-methyl- is produced from the downstream breakdown of leucine [ 25 ]. 2-phenylethyl alcohol is produced from the degradation of aromatic amino acids [ 6 ] via the shikimate pathway [ 26 ]. These core alcohols that both Candida species emitted are not characteristic and are common metabolic products that are widely emitted across both bacterial and fungal kingdoms [ 6 , 11 , 22 , 27 ].…”

Valorization of Brewers’ Spent Grains: Pretreatments and Fermentation, a Review

“…Particularly, microbial fermentation is a promising biovalorization method for this highvolume industrial byproduct [2]. For instance, it was reported that this cheap feedstock was used to naturally produce the valuable aromatic compound 2-phenylethanol through microbial fermentation mainly using yeasts, competing with the conventional, environmentally unfriendly, chemical synthesis routes [15]. A simplified scheme of the brewing process, BSG constituents, and their uses, is illustrated in Figure 1.…”