Microbial Production of Renewable Acrylic Acid

Introduction

Acrylic acid is a high-demand industrial monomer used in superabsorbent polymers (SAPs), paints, coatings, adhesives, and textiles. Traditionally, it is produced via the oxidation of propylene, a fossil-based process that emits large quantities of CO₂ and relies heavily on petrochemical feedstocks.

With increasing emphasis on sustainability, there is growing momentum behind the renewable production of acrylic acid via engineered microbes, capable of converting sugars or biomass-derived intermediates into 3-hydroxypropionic acid (3-HP) or directly into acrylic acid. This microbial route offers a greener alternative, leveraging synthetic biology and metabolic engineering to create drop-in biobased substitutes for conventional acrylic acid

What Products Are Produced?

• Acrylic Acid (C₃H₄O₂) – Primary bio-based monomer
• 3-Hydroxypropionic Acid (3-HP) – Key intermediate
• Methyl Acrylate and Ethyl Acrylate – Esters derived from acrylic acid for adhesives and coatings
• Polyacrylics – SAPs, thickeners, and dispersants

Pathways and Production Methods

1. Fermentative Production of 3-Hydroxypropionic Acid (3-HP)

• Feedstocks: Glucose, glycerol, xylose
• Engineered microbes (e.g., E. coli, Klebsiella, Lactobacillus) produce 3-HP via:
• Malonyl-CoA pathway (from acetyl-CoA via malonyl-CoA reductase)
• β-alanine pathway (from L-aspartate via aspartate decarboxylase and β-alanine-pyruvate aminotransferase)

2. Catalytic Dehydration of 3-HP to Acrylic Acid

• Dehydration using acid catalysts (zeolites, metal oxides, supported phosphates)
• Typical yields >85% in optimized systems
• Hybrid process: fermentation followed by thermochemical conversion

3. One-Pot Microbial Acrylic Acid Synthesis

• Direct pathway engineering (experimental): insertion of decarboxylase and dehydratase modules into microbes
• Goal: Bypass intermediate separation and improve process efficiency

Catalysts and Key Tools Used

• Microbial Hosts:
• Escherichia coli, Klebsiella pneumoniae, Corynebacterium glutamicum, Saccharomyces cerevisiae
• Key Enzymes:
• Malonyl-CoA reductase (MCR)
• β-alanine-pyruvate aminotransferase
• Dehydratases for 3-HP → acrylic acid conversion
• Catalysts for Dehydration:
• Silica-alumina, ZrO₂, tungsten oxide, phosphoric acid-supported catalysts
• Techniques:
• Fed-batch fermentation, membrane separation, continuous catalytic dehydration reactors

Case Study: Cargill & Novozymes – BioAcrylic Project

Highlights

• Developed microbial fermentation route from glucose to 3-HP, followed by catalytic dehydration
• Yielded >80 g/L 3-HP in pilot fermentation
• Demonstrated bioacrylic acid with properties equivalent to fossil-derived acrylic acid
• Targeted application in baby diapers, paints, and hygiene products

Timeline

• 2011 – BioAcrylic joint venture initiated
• 2014 – Pilot production of 3-HP
• 2017 – Acrylic acid synthesized at 500 kg scale
• 2020 – Project paused; IP licensed to other companies for scaling

Global and Indian Startups Working in This Area

Global

• Cargill–Novozymes (USA/Denmark) – Fermentative 3-HP to acrylic acid
• OPX Biotechnologies (USA) – Engineered E. coli for 3-HP
• BASF – Investigated catalytic dehydration routes from biobased 3-HP
• Metabolic Explorer (France) – Commercial production of 3-HP from glycerol

India

• IIT Delhi & CSIR-IIP – Research on glycerol and sugar fermentation to 3-HP
• IIT Guwahati – Pilot studies on bioacrylic acid from renewable sugars
• Godavari Biorefineries – Exploring integration into biorefinery platform
• ICT Mumbai – Hybrid biocatalytic–thermocatalytic route under development

Market and Demand

The global acrylic acid market stood at USD 14.2 billion in 2023, with projections reaching USD 19.8 billion by 2030, growing at a CAGR of ~4.8%. The biobased segment is gaining traction due to demand from green superabsorbents and coatings.

Major Use Segments:

• Hygiene products – Diapers, adult incontinence, sanitary pads (SAPs)
• Paints and coatings – Emulsions, binders
• Adhesives and sealants – Pressure-sensitive adhesives
• Textile and leather – Finishing agents

Key Growth Drivers

• Volatile fossil propylene prices and supply issues
• Push for biodegradable and low-carbon SAPs
• Surplus glycerol and biomass sugars as feedstocks
• Consumer demand for eco-labels in hygiene products
• Regional policies banning high-emission monomers

Challenges to Address

• High cost of microbial fermentation at commercial scale
• Need for robust microbes with high 3-HP productivity
• Catalyst selectivity and deactivation in dehydration step
• Integration into existing acrylic acid infrastructure
• In India: Need for investment in pilot-scale biorefineries

Progress Indicators

• 2009–2012 – Identification of microbial 3-HP pathways
• 2014 – Pilot-scale fermentation by global consortia
• 2018 – Catalytic dehydration process optimization
• 2022 – Research resurgence as SAP companies seek green alternative
• 2024 – India starts evaluating biomass-to-3-HP bioplatforms

The microbial route to acrylic acid is at TRL 6–8 globally, with demo-scale production validated. In India, projects are at TRL 4–6, with key efforts focused on 3-HP production and catalytic integration.

Conclusion

The microbial production of renewable acrylic acid represents a promising pathway to decarbonize a high-volume monomer used in everyday products. Through engineered microbes, catalytic innovations, and hybrid processing, this route offers a cleaner alternative to fossil-derived acrylic acid.

As India’s biomanufacturing capacity expands, and global industries look for green SAPs and coatings, microbial acrylic acid could become a cornerstone of circular, climate-smart chemistry.

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