Nitrogen‐Neutral Amino Acids Refinery: Deamination of Amino Acids for Bio‐Alcohol and Ammonia Production

Abstract

Amino acids are a valuable bioresource that contains both the acid form of carbon and the amine group of nitrogen. Amino acids not only constitute proteins and the building blocks for living organisms but also provide a key intermediate for controlling the nitrogen balance in cells. The production of amino acids using microorganisms has, along with the development of biotechnology, created a large market for biochemicals. In parallel, there have been various biochemical production methods using pulmonary proteins or direct amino acids as biomass through enzymatic bioconversion or whole‐cell biotransformation. The deamination of amino acids facilitated the applications of 2‐keto and acrylic acids, in particular, for biofuels of bio alcohol, pharmaceuticals, cosmetics, as building blocks for polymers, and other versatile industrial chemicals. In this review, we report on the application of amino acids derived from biochemicals initiated by deamination reactions using deaminase, ammonia‐lyase, and oxidase enzymes for biotechnology applications.

Selective Biocatalytic Defunctionalization of Raw Materials

“…Among the various enzymes involved in formally removing nitrogen from amino acids, the amino acid lyases are straightforward to use in N-defunctionalizations, as they are the only ones that do not require oxygen, an external nicotinamide adenine dinucleotide (NAD + ) cofactor, or an amine acceptor. [148] The reversible elimination of nitrogen from l-amino acids, in the form of ammonia, is catalyzed by l-amino acid ammonia lyases, which have attracted much interest for applications in the reverse direction. [149,150] On the other hand, making available selected l-amino acids, α,ω-dicarboxylic acids, and α,β-unsaturated carboxylic acids from l-amino acids may not only provide opportunities for valorizing biobased raw materials, [148,151] but also for N-defunctionalization applications (see Scheme 11).…”

“…Carbon‐nitrogen lyases ( C ‐ N ‐lyases) catalyzing the elimination of ammonia are important for maintaining nitrogen metabolism and health. Among the various enzymes involved in formally removing nitrogen from amino acids, the amino acid lyases are straightforward to use in N ‐defunctionalizations, as they are the only ones that do not require oxygen, an external nicotinamide adenine dinucleotide (NAD + ) cofactor, or an amine acceptor [148] . The reversible elimination of nitrogen from l ‐amino acids, in the form of ammonia, is catalyzed by l ‐amino acid ammonia lyases, which have attracted much interest for applications in the reverse direction [149,150] .…”

“…[148] The reversible elimination of nitrogen from l-amino acids, in the form of ammonia, is catalyzed by l-amino acid ammonia lyases, which have attracted much interest for applications in the reverse direction. [149,150] On the other hand, making available selected l-amino acids, α,ω-dicarboxylic acids, and α,β-unsaturated carboxylic acids from l-amino acids may not only provide opportunities for valorizing biobased raw materials, [148,151] but also for N-defunctionalization applications (see Scheme 11). Aromatic amino acid ammonia lyases are valuable for the sustainable preparation of phenylpropanoids, for example, in the synthesis of trans-cinnamic acid and p-coumaric acid, [152] also as starting reaction in a biocatalytic reaction cascade in one-pot to valuable chiral chemicals.…”

Toward bioproduction of oxo chemicals from C1 feedstocks using isobutyraldehyde as an example

“…To address this issue, an ideal way is to utilize protein-based refinery to recycle the nitrogen source from the protein-rich residuals while realizing carbon–neutral biomanufacturing. Protein-based refinery is also termed as nitrogen–neutral amino acids refinery, which uses a deamination or transamination process to release carbon skeletons for chemicals production while recycling nitrogen in the form of ammonia [ 64 ]. Specifically, enzymes converting amino acids to the corresponding α-keto acids or tricarboxylic acid (TCA) cycle intermediates were introduced into the hosts to generate the precursors for chemical production.…”

Construction of Co/Ni-tcbpe Crystalline Framework Structures and the Inspiration for Fluorescence “Turn-On” Behavior toward Asp

“…Amino acid is the basic unit of protein. , Aspartic acid is a common acidic amino acid, belonging to one of the nonessential amino acids of the human body. In medicine, aspartic acid can be used to treat heart disease, hypertension, etc.…”