ABSTRACT
2-Phenylethanol (2-PE) is an alcohol that emits an aroma of the fresh and delicate roses. Natural 2-PE is present in many plants, especially in the rose oil. Because of its delicate aroma and sweet taste, 2-PE is the second-most commonly used flavor after vanillin. 2-PE and its high valued derivatives can be used in food, tobacco, and cosmetics industries. The global annual output of 2-PE is nearly 10,000 tons in 2010. Chemical synthesis is the basic method used to produce 2-PE. However, benzene or styrene—the raw materials used to synthesize 2-PE—are regulated chemicals. Methods to produce natural 2322-PE include plant extraction and microbial transformation. The production of 2-PE through biotransformation presents broad application prospects. Several microorganisms can produce 2-PE. However, yeasts with generally recognized as safe (GRAS) designation Kluyveromyces marxianus and Saccharomyces cerevisiae stand out among them. The drawback of the biocatalytic process is the inhibition of yeast growth by the accumulating product. To overcome this challenging limitation, production strategies have been developed, including identification of highly productive microorganism, biocompatible in situ product removal techniques (ISPR), use of industrial wastes as substrates, and more recently, genetic modification of microorganisms.
