Diamine Biosynthesis: Research Progress and Application Prospects

Abstract

Diamines are important monomers for polyamide plastics; they include 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, and 1,6-diaminohexane, among others. With increasing attention on environmental problems and green sustainable development, utilizing renewable raw materials for the synthesis of diamines is crucial for the establishment of a sustainable plastics industry. Recently, high-performance microbial factories, such as Escherichia coli and Corynebacterium glutamicum, have been widely used in the production of diamines. In particular, several synthetic pathways of 1,6-diaminohexane have been proposed based on glutamate or adipic acid. Here, we reviewed approaches for the biosynthesis of diamines, including metabolic engineering and biocatalysis, and the application of bio-based diamines in nylon materials. The related challenges and opportunities in the development of renewable bio-based diamines and nylon materials are also discussed.

Keywords: biosynthesis; diamines; metabolic engineering; nylon.

FIG 1

Microbial metabolic C₄ pathways for diamine production. Orange arrows represent metabolic pathways of 1,3-diaminopropane; yellow arrows represent metabolic pathways of 1,5-diaminopentane; black arrows represent conventional metabolic pathways; dashed lines represent multistep reactions. PfkA/PfkB, 6-phosphofructokinase; FbaA/B, fructose-bisphosphate aldolase; GapA/C, glyceraldehyde-3-phosphate dehydrogenase; PykF, pyruvate kinase I; PykA, pyruvate kinase II; Pfo, pyruvate-flavodoxin oxidoreductase; AceE/AceF, pyruvate dehydrogenase; Pyc, pyruvate carboxylase; GltA, citrate synthase; AcnAB, aconitate hydratase; Icd, isocitrate dehydrogenase; SucAB, α-ketoglutarate dehydrogenase; SucCD, succinyl-CoA synthetase; Frd, fumarate reductase; Sdh, succinate dehydrogenase; Fum, fumarate hydratase; Mdh, l-malate-NAD⁺ oxidoreductase; Mqo, l-malate-quinone oxidoreductase; Pck, phosphoenolpyruvate carboxykinase; Ppc, the phosphoenolpyruvate carboxylase; AspC, aspartate aminotransferase; LysC, aspartate kinase; Asd, aspartate-semialdehyde dehydrogenase; Dat, diaminobutyrate-2-oxoglutarate transaminase; Ddc, l-2,4-diaminobutyrate decarboxylase; DapA, dihydrodipicolinic acid synthase; DapB, 4-hydroxy-tetrahydrodipicolinate reductase; Ddh, meso-diaminopimelate dehydrogenase; LysA, diaminopimelic acid decarboxylase; LdcC, l-lysine decarboxylase II; CadA, l-lysine decarboxylase I; YgjG, putrescine/α-ketoglutarate aminotransferase; PuuA, γ-glutamylputrescine synthase; PuuP, putrescine importer; SpeE, spermidine synthase; SpeG, spermidine N-acetyltransferase; NCgl1469, 1,5-diaminopentane acetyltransferase; CadB, 1,5-diaminopentane/l-lysine antiporter; CgmA, putrescine/1,5-diaminopentane exporter.

FIG 2

Microbial metabolic C₅ pathways for diamine production. Orange arrows represent metabolic pathways of 1,3-diaminopropane; blue arrows represent metabolic pathways of putrescine; black arrows represent conventional metabolic pathways; dashed lines represent multistep reactions. AspC, aspartate aminotransferase; AlaA, glutamate-pyruvate aminotransferase; ProB, glutamate 5-kinase; ArgA, amino acid N-acetyltransferase; ArgB, acetylglutamate kinase; ArgR, transcriptional regulator of arginine metabolism; ArgC, N-acetyl-gamma-glutamylphosphate reductase; ArgD, N-acetyl-l-ornithine aminotransferase; ArgE, acetylornithine deacetylase; ArgJ, l-glutamate N-acetyltransferase; GlnA, glutamine synthetase; CarAB, carbamoyl-phosphate synthetase; ArgI, ornithine carbamoyltransferase 1; ArgF, N-acetylornithine carbamoyltransferase; SpeC, ornithine decarboxylase; SpeF, ornithine decarboxylase isozyme; ArgG, citrulline-aspartate ligase; ArgH, arginosuccinase; SpeA, l-arginine decarboxylase; SpeB, agmatine ureohydrolase; AstA, arginine succinyltransferase; PotE, putrescine/l-ornithine antiporter; PatA, putrescine aminotransferase; SpdH, spermidine dehydrogenase; MTA, methylthioadenosine.

FIG 3

Metabolic pathways for 1,6-diaminohexane. The black arrow represents route 1. The orange arrow represents route 2. The blue arrow represents route 3. Key enzymes were as follows: hydrogenase, 1; hydrolase, 2; aminase, 3; oxidase, 4; reductive aminase, 5; hydrodeoxygenase, 6; glutamyl-CoA transferase and/or ligase, 7; beta-ketothiolase, 8; 2-oxo-acid reductase, 9; dehydratase, 10; acyl-CoA dehydrogenase, 11; dehydrogenase, 12; amine dehydrogenase, 13; homolysine decarboxylase, 14; carboxylic acid reductases, 15; transaminase, 16.

FIG 4

The biological enzymatic synthesis of dapdiamide with two amide bonds. DdaG, adenylate-forming ligases; DdaH, amidotransferase; DdaF, ATP-grasp enzyme.