Advances in biosynthesis of 2-phenylethanol by yeasts / 生物工程学报

2-Phenylethanol (2-PE) is an aromatic alcohol with a pleasant rose-like fragrance. It has been widely used in food, cosmetic, and pharmaceutical industry. Most of 2-PE is produced by chemical synthesis, but the use of chemically synthesized product is restricted in some fields. 2-PE from plant extraction is natural but its production is very low. Microbial biotransformation is a promising process to produce natural 2-PE. In this paper, we review recent research progress in the synthetic metabolic pathways and regulatory processes of 2-PE in yeast, and strategies for improving 2-PE production. Moreover, we discuss the limitation of current progress and future research directions.

Effects of aroma quality on the biotransformation of natural 2-phenylethanol produced using ascorbic acid

Background Natural 2-phenylethanol (2-PE) is an important flavoring that emits the aroma of roses. During biotransformation, the aroma quality of natural 2-PE is affected by its main by-products, which include butanol, isobutyric acid, butyric acid, and isovaleric acid. Thus, controlling undesirable by-product formation can reduce the effect of odor on 2-PE aroma quality. Results 2-PE was produced through biotransformation using l-phenylalanine as a substrate and glucose as a carbon source. Ascorbic acid was added to the system to improve the redox reaction and suppress the generation of by-products. Principal component analysis of the aroma quality of 2-PE was performed using an electronic nose. Similarity analysis revealed that the effects of four by-products on 2-PE aroma quality may be ranked in the following order: isovaleric acid > butyric acid > isobutyric acid > butanol. The sample that exhibited the best similarity to the standard 2-PE sample (99.19%) was the sample to which ascorbic acid had been added during glucose metabolism. Conclusions 2-PE produced through the addition of ascorbic acid exhibited the closest aroma similarity to the standard 2-PE sample.