Carboxylic acid reductases (CARs): An industrial perspective

•Carboxylic acid reductases (CARs) chemoselectively reduce carboxylic acids to aldehydes.•CARs are Mg2+, ATP and NADPH dependent and can be applied in vivo or in vitro with cofactor recycling.•CARs have been applied in a variety of biocatalytic cascades to date.•CARs are promising industrial biocatalysts although more development is required for robustness and scalability. Carboxylic acid reductases (CARs) are an emerging biocatalyst platform for the synthesis of a diverse array of aldehydes from carboxylic acids, operating chemoselectively and under mild aqueous conditions. As such, there is growing interest in the industrial application of these enzymes, both for the synthesis of aldehyde end-products, which are particularly prevalent in the flavor and fragrance industries, and aldehyde intermediates in multi-enzyme cascades. This perspective aims to review recent developments in the applications of CARs with a focus on the challenges and considerations involved in their implementation, as well as potential solutions with a view to increased industrial utility.