May. 14, 2021
Cinnamyl alcohol is not only a flavor and fragrance but also a versatile chemical used in the production of various compounds. Currently, the preparation of cinnamyl alcohol depends on plant extraction and chemical synthesis, which has several drawbacks, including scalability, productivity, and limited environmental impact. Therefore, there is a need to develop an effective, green, and sustainable biosynthesis method. The Cinnamyl alcohol supplier will share it with you.
In recent years, due to the rapid consumption of fossil fuels and the growing demand for aromatic compounds, there has been an increasing interest in the production of these compounds from plant sources. Lignin monohydrates, units of plant lignin, are important aromatic compounds that can be used to produce a variety of commercially significant and high-value chemicals. They are of great interest along with the development of market demand. However, most natural monolignols are available in low concentrations in plants and their extraction is limited by plant growth and expensive downstream processing costs. Industrial biosynthesis offers a promising alternative approach as it allows the large-scale production of natural monolignols from biological resources.
Cinnamyl alcohol (a naturally occurring aromatic alcohol) is the backbone of monolignols. Cinnamyl alcohol is not only used in the food and cosmetic industries due to its sweet pungent odor and taste of cinnamon but also shows good anti-inflammatory and antibacterial activity. In addition, cinnamyl alcohol is a versatile chemical used in the synthesis of various valuable compounds such as cinnamate (which is a flavoring and aromatic agent), flunarizine (used in the treatment of fungal infections), paclitaxel (used in cancer treatment) drugs) and cinnamyl glycosides (for their immune-enhancing properties). Cinnamyl alcohol is also synthesized via the monolignol pathway in plants and biotechnology has been reported for the production of natural cinnamyl alcohol by introducing the plant monolignol pathway into microbial strains.
Higher concentrations of cinnamyl alcohol can be obtained through whole-cell biotransformation by introducing the M. trichocarpa pathway into E. coli.BL21 (DE3). However, the current production of cinnamyl alcohol using this strategy is still unsatisfactory, as most of the characterized 4CLs show low activity towards cinnamic acid. Therefore, a novel artificial approach was designed to mimic the microbial pathway and recombinant brewer's yeast strains expressing Arabidopsis PAL2 (AtPAL2), carboxylic acid reductase from Arabidopsis Nocardia (NoCAR), and pantotransferase from Pantothenic acid.
Escherichia coli (EcSFP) was designed to biotransform 1-phenylalanine to cinnamic alcohol. When using endogenous reductase in Saccharomyces cerevisiae, the maximum concentration of cinnamic alcohol was 0.83 mM when 1.35 mM cinnamic acid was added to the medium. Klumbys et al. established a three-step cascade reaction using PAL, CAR, and ADH to synthesize approximately 4.3 mM cinnamyl alcohol from 5 mM 1-phenylalanine after 27.5 hr. These findings suggest that the biosynthesis of cinnamyl alcohol from the CAR pathway via microorganisms is feasible and avoids the problems associated with 4CL. However, the reduction of cinnamic acid to cinnamyl alcohol remains the limiting module in the cinnamyl alcohol biosynthetic pathway. To our knowledge, enhanced biosynthetic strategies to overcome product inhibition have not been explored. There are no reports on the reduction of cinnamic acid to cinnamyl alcohol in E. coli using heterologous CAR and endogenous ADH or AKR.
Here, we report a novel, high-yield biphasic biotransformation for the one-pot, two-step biosynthesis of cinnamyl alcohol from cinnamic acid. Recombinant Escherichia coli strain BLCS, co-expressing CAR from Acinetobacter eikanoides (Nicar) and SFP from Bacillus subtilis (BsSFP), catalyzes the one-step reduction of cinnamic acid to cinnamic aldehyde. Cinnamic aldehyde was then converted to cinnamyl alcohol by endogenous ADH and AKR. Subsequently, cinnamyl alcohol was shown to exert a severe product inhibition on its biosynthesis and was overcome for the first time by in situ product removal using a biphasic system.