Production of Biobased Caprolactam via Fermentation

Introduction

Caprolactam is a vital intermediate chemical used almost exclusively for manufacturing nylon-6, a widely used engineering polymer in textiles, automotive, industrial fibers, and packaging. Traditional production methods are petrochemical-intensive, relying on cyclohexanone and ammonia derived from benzene, releasing significant greenhouse gases and waste.

To transition toward green polymers, the fermentative production of biobased caprolactam has emerged as a strategic pathway. Leveraging metabolic engineering, synthetic biology, and bio-process innovation, researchers aim to convert renewable sugars or biomass-derived intermediates into caprolactam using engineered microbes, offering a drop-in alternative for nylon-6 production.

What Products Are Produced?

Biobased Caprolactam

• Feedstock for nylon-6 fibers and films
• Used in textiles, carpets, automotive plastics, electronics
• Potential platform for biobased polyamide copolymers

Pathways and Production Methods

1. 6-Aminocaproic Acid (6-ACA) Pathway

• Glucose → L-lysine → 6-ACA → Caprolactam (via cyclization)
• Involves lysine monooxygenase, caprolactam synthase
• Cyclization step can be enzymatic or chemical

2. Muconic Acid to Caprolactam

• Glucose → Shikimate → cis,cis-Muconic acid → Adipic acid → Caprolactam
• Multi-step fermentation followed by catalytic ring closure

3. Hybrid Routes

• Fermentative production of precursors (e.g., 6-ACA or ε-aminocaproic acid), then chemoenzymatic conversion to caprolactam

Catalysts and Key Tools Used

Engineered Microorganisms:

• Corynebacterium glutamicum, E. coli – L-lysine and 6-ACA production
• Saccharomyces cerevisiae – Shikimate and muconic acid pathways
• Bacillus megaterium – For ε-caprolactam analogs

Key Enzymes:

• Lysine monooxygenase (LMO) – Converts lysine to 6-ACA
• 6-ACA cyclase – Cyclizes to caprolactam
• Muconate cycloisomerase – In shikimate-to-adipate route

Process Enhancements:

• Fed-batch fermentation with pH and oxygen control
• Pathway modularization to reduce feedback inhibition
• Integrated purification and recovery of lactam

Case Study: DSM & Genomatica – Biobased Caprolactam Pilot

Highlights

• Created engineered E. coli to convert glucose to 6-ACA and caprolactam
• Achieved high selectivity in caprolactam cyclization
• Targeted nylon-6 fibers for sustainable textiles
• Demonstrated feasibility at demo scale

Timeline

• 2013 – Pathway design and early proof-of-concept
• 2016 – 6-ACA yields optimized using Corynebacterium
• 2019 – Pilot plant run for biobased caprolactam
• 2023 – Nylon-6 yarns tested for commercial integration

Global and Indian Startups Working in This Area

Global

• Genomatica (USA) – Bio-caprolactam pathway R&D
• DSM (Netherlands) – Collaborating on bio-nylon value chain
• Evonik (Germany) – L-lysine to ε-lactam work
• Metabolic Explorer (France) – Pilot scale for polyamide monomers

India

• ICT Mumbai – Fermentative conversion of lysine to lactams
• IIT Kharagpur & CSIR-IICT – Enzyme development for lactam cyclization
• Biotech startups via BIRAC – Exploring bio-nylon supply chain integration
• Godavari Biorefineries – Investigating lysine-based monomer streams

Market and Demand

The global caprolactam market was valued at USD 15.2 billion in 2023, expected to reach USD 21.5 billion by 2030, growing at CAGR ~5.1%. Biobased caprolactam is expected to grow faster (~13% CAGR) due to sustainability mandates in textiles, automotive, and industrial fibers.

Major End-Use Segments:

• Nylon-6 fibers and yarns – Apparel, carpets, sportswear
• Automotive plastics – Engine covers, under-the-hood parts
• Engineering resins – Electrical and electronic casings
• Industrial packaging and films

Key Growth Drivers

• Demand for green and circular textiles
• Push for decarbonized engineering polymers
• Abundant glucose and lysine as feedstocks
• Compatibility with existing nylon-6 infrastructure
• Supportive policies for green chemistry and biobased materials

Challenges to Address

• Low titers and productivity of 6-ACA in microbes
• Incomplete cyclization efficiency in vivo
• Scale-up of integrated fermentation and ring-closure
• High purification costs for polymer-grade caprolactam
• India-specific: Need for downstream buyers in nylon-6 fiber markets

Progress Indicators

• 2013–2015 – First successful conversion of lysine to 6-ACA
• 2017 – Lab-scale microbial cyclization to caprolactam
• 2019 – Pilot plant trials of fermentation route
• 2021 – Indian labs initiate pathway replication
• 2024 – Ongoing tech transfer discussions with fiber manufacturers

Biobased caprolactam is at TRL 6–7 globally, with demo-scale validation and early product testing; in India, it is at TRL 4–5, with lab and pilot pathway development ongoing.

Conclusion

Fermentation-based production of caprolactam represents a pivotal leap in making nylon-6 truly sustainable, replacing benzene-derived fossil inputs with renewable sugar-based pathways. By engineering microbes to produce 6-ACA and cyclize it to caprolactam, the industry is closing the loop on low-emission, high-performance polymers.

For India, tapping into this domain aligns with its textile leadership, sugar economy, and growing biopolymer innovation ecosystem—marking the next chapter in bio-based manufacturing at scale.

Wish to have bio-innovations industry or market research support from specialists for climate & environment? Talk to BioBiz team – Call Muthu at +91-9952910083 or send a note to ask@biobiz.in