Investigation of fatty aldehyde and alcohol synthesis from fatty acids by αDox- or CAR-expressing Escherichia coli

Publication date: Available online 17 August 2019Source: Journal of BiotechnologyAuthor(s): Susanne Maurer, Hendrik Schewe, Jens Schrader, Markus BuchhauptAbstractFatty aldehydes are among the most important flavor and fragrance compounds. Most biotechnological production approaches make use of the one step conversion of fatty acids from renewable sources by the enzymes α-dioxygenase (αDox) or carboxylic acid reductase (CAR). Their reaction mechanisms and cofactor dependencies are very different. In contrast to heme-containing αDox which requires only oxygen as cosubstrate, CAR needs NADPH and ATP, which is a clear argument for the application of a whole cell catalyst. Therefore we compared fatty acid biotransformations with growing Escherichia coli cells expressing αDox or CAR to investigate their suitability for fatty aldehyde and also fatty alcohol production. Our results show the main product of fatty acid conversions with αDox-expressing cells to be the expected Cn-1 aldehyde. However, 14 % of the products consist of the corresponding alcohol, but in addition, 17 % of the products consist of further shortened aldehydes, alcohols and acids that result from the consecutive activity of αDox and a putative endogenous fatty aldehyde dehydrogenase activity in E. coli. Conversely, CAR-expressing cells produced only the unshortened fatty aldehyde and alcohol, whereby the latter surprisingly accounts for at least 80 % of the products. The considerably higher extend of aldeh...
Source: Journal of Biotechnology - Category: Biotechnology Source Type: research