Bio-based Production of Adipic Acid from Sugars

Introduction

Adipic acid (hexanedioic acid) is a key industrial dicarboxylic acid primarily used in the production of nylon-6,6, polyurethanes, plasticizers, and resins. Conventionally produced from petroleum-based cyclohexane via oxidation, this process emits significant quantities of nitrous oxide (N₂O)—a potent greenhouse gas.

In the push toward decarbonization and sustainable materials, researchers and companies are exploring the bio-based production of adipic acid from renewable sugars, including glucose, fructose, and lignocellulose-derived hydrolysates. Using engineered microbes, synthetic metabolic pathways, and green chemistry, this approach enables low-carbon, renewable alternatives for high-volume polymer feedstocks.

What Products Are Produced?

Bio-based Adipic Acid

• Used in nylon-6,6 polymer production
• Precursors for polyurethanes and plasticizers
• Used in coatings, solvents, and food additives

Derivatives:

• Adipate esters – Phthalate-free plasticizers
• PBS blends – Bioplastics with improved flexibility

Pathways and Production Methods

1. Reverse Adipate Degradation Pathway (RADP)

• Glucose → Acetyl-CoA + Succinyl-CoA → 6-carbon intermediate → Adipic acid
• Engineered in E. coli and Thermobifida fusca

2. Muconic Acid Intermediate Route

• Glucose → Shikimate pathway → cis,cis-muconic acid → Hydrogenation → Adipic acid

3. α-Ketoadipate Pathway

• Lignin-derived aromatics → Protocatechuate → α-ketoadipate → Reduction → Adipic acid

4. Fatty Acid β-Oxidation Modification

• Tailoring chain-shortened fatty acids through oxidation and decarboxylation

Catalysts and Key Tools Used

Engineered Microorganisms:

• E. coli, Corynebacterium glutamicum, Pseudomonas putida – Sugar-based routes
• Saccharomyces cerevisiae – Shikimate to muconate conversions
• Thermobifida fusca – Hosts for thermophilic RADP implementation

Key Enzymes:

• 2-oxoadipate dehydrogenase, adipyl-CoA synthetase
• Muconate cycloisomerase, muconate reductase
• Dehydrogenases, transferases, and isomerases for synthetic pathway tuning

Bioprocess Tools:

• Fed-batch glucose fermentation
• pH-controlled bioreactors for acid stability
• In situ product removal to minimize toxicity

Case Study: Verdezyne (USA) – Bio-Adipic Acid from Palm-Derived Glycerol

Highlights

• Engineered Candida yeast to produce adipic acid from glycerol and sugars
• Used proprietary synthetic pathway with high yield
• Targeted nylon, plasticizer, and solvent markets
• Demonstrated cost parity with fossil adipic acid

Timeline

• 2010 – Lab-scale development of engineered yeast
• 2014 – Pilot-scale production validated
• 2017 – Commercial demonstration plant initiated in Malaysia
• 2019 – Company assets acquired for process integration

Global and Indian Startups Working in This Area

Global

• Verdezyne (USA/Malaysia) – Bio-adipic acid from glycerol and sugars
• Genomatica (USA) – Developing sugar-based pathways to C6 dicarboxylic acids
• DSM (Netherlands) – Shikimate-based adipic acid pathways
• AFYREN (France) – Producing volatile fatty acids including adipate precursors

India

• CSIR-NIIST, Trivandrum – Lignocellulose to muconic acid route
• IIT Delhi, ICT Mumbai – Engineering E. coli for sugar-to-adipate conversion
• BIRAC-supported biotech startups – Focusing on fermentation of C6 acids
• Godavari Biorefineries – Evaluating adipic acid integration into nylon-6,6 chain

Market and Demand

The global adipic acid market was valued at USD 6.1 billion in 2023, projected to reach USD 8.4 billion by 2030, with bio-based adipic acid expected to grow at ~12% CAGR, driven by nylon manufacturers, green construction, and automotive plastics.

Major End-Use Segments:

• Nylon-6,6 fibers and plastics – Automotive, textiles
• Polyurethanes – Foams, adhesives
• Plasticizers and solvents – PVC replacement
• Food & pharma – Acidity regulator, buffering agent

Key Growth Drivers

• Regulatory pressure to eliminate N₂O emissions from fossil processes
• Abundant supply of renewable sugars and glycerol
• Demand for drop-in bio-based nylon
• Interest in non-phthalate plasticizers
• Integration with biorefineries and agro-waste valorization

Challenges to Address

• Low productivity and titers in microbial hosts
• Product toxicity and feedback inhibition
• Hydrogenation step (muconic acid route) adds chemical complexity
• Need for integrated biorefineries for economic viability
• Scale-up and downstream purification challenges

Progress Indicators

• 2010 – First microbial conversion of sugars to adipic acid reported
• 2015 – Pilot-scale muconate-to-adipate conversion
• 2017 – First bio-adipic demonstration plant (Verdezyne)
• 2022 – India develops sugar-to-adipate fermentation at lab scale
• 2024 – BIRAC and DBT initiate technology transfer for biobased adipate

Bio-based adipic acid production is at TRL 7–8 globally, with pre-commercial demonstration completed; in India, the process is at TRL 4–5, with lab-scale and pilot fermentation optimization ongoing.

Conclusion

The bio-based production of adipic acid from sugars represents a critical innovation for sustainable polymer production, reducing reliance on fossil fuels and curbing greenhouse gas emissions. With applications in nylon, coatings, and bioplastics, it has the potential to reshape supply chains in automotive, textile, and chemical industries.

As India invests in sugar-based biorefineries and green nylon development, bio-adipic acid can become a core building block for a circular, low-carbon material economy.

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