# Biosynthetic acrylamide (flocculants & bio-acrylamide)

Enzymatic conversion of acrylonitrile to acrylamide via immobilized Rhodococcus rhodochrous cells, replacing copper-catalyzed synthesis for water-treatment, mining and papermaking flocculants.

Source: https://en.bioecon.ru/technology/biosynthetic-acrylamide-flocculants/
Updated: 2026-08-18



## Overview and value chain

Markers: [EC: Circular Bioeconomy Strategy & REACH Regulation | OECD: industrial-biotech | Regulator: EPA (US), REACH (EU), NMPA (CN)]

Biosynthetic acrylamide replaces the older sulfuric-acid and copper-catalyzed route to acrylamide with enzymatic biocatalysis: immobilized cells of *Rhodococcus rhodochrous*, carrying a highly active nitrile hydratase enzyme, hydrate acrylonitrile directly into acrylamide at greater than 99.9% yield without generating toxic copper-laden wastewater. The resulting bio-acrylamide is then polymerized — alone or with cationic comonomers — into high-molecular-weight polyacrylamide (PAM) flocculants used to dewater sludge, clarify mining process water and improve paper-sheet drainage. SNF Group markets its FLOMIN TFA line of solid-liquid separation aids for mining, spanning high-performance flocculants for thickening, inline flocculation and centrifugation. Kemira's Superfloc RH4821 anionic rheology modifier outperformed a previous flocculant in a full-scale tailings-thickening trial at a Brazilian mining site, and the company's Superfloc BioMB line applies a biomass-balanced approach to polyacrylamide flocculants for wastewater treatment. Kurita's Kuriflock Green Technology offers a new generation of biopolymer-based coagulants and flocculants as an alternative to fossil-based polymers, alongside the company's broader PFAS water-treatment portfolio. In China, ChemCubic manufactures polyacrylamide products for oilfield drilling, enhanced oil recovery and wastewater treatment.

The key directions of biosynthetic acrylamide are:
1. **Enzymatic acrylamide synthesis:** hydrating acrylonitrile to acrylamide with immobilized nitrile-hydratase-producing bacteria instead of copper or sulfuric-acid catalysis, eliminating toxic metal-laden waste streams.
2. **High-molecular-weight bio-PAM:** polymerizing bio-acrylamide, alone or with cationic comonomers, into polyacrylamide flocculants with molecular weights exceeding 15-20 million Daltons for water treatment, mining and papermaking.
3. **Natural cationic flocculants:** chitosan (from crustacean shells or fungal cell walls) and cationic-modified starches as biodegradable alternatives to synthetic PAM for sludge dewatering and effluent clarification.
4. **Ultra-low residual-monomer purity:** enzymatic synthesis routes engineered to leave near-zero unreacted acrylonitrile/acrylamide monomer, addressing the neurotoxicity and carcinogenicity concerns of the free monomer.

### Sectoral value chain

```
[Precursors & Feedstock] ──> [Biocatalysis & Synthesis] ──> [Gel Polymerization] ──> [Granulation & Drying]
                                                                                              │
                                                                                    (Water/mining/paper markets)
                                                                                              │
                                                                                              ▼
[Regulatory Compliance (EPA/REACH)] <─── [QA/QC: Residual Monomer, Molecular Weight]
```

### Value chain levels

| Level | Description | Key inputs/outputs |
|:---|:---|:---|
| **1. Feedstock and precursors** | Sourcing acrylonitrile and, for natural flocculants, crustacean chitin/chitosan or cationic starches. | **In:** Acrylonitrile, chitin/starch feedstock.<br>**Out:** Qualified reaction feedstock. |
| **2. Biocatalytic synthesis** | Hydrating acrylonitrile to acrylamide using immobilized nitrile-hydratase bacterial cells. | **In:** Acrylonitrile, immobilized *R. rhodochrous* catalyst, water.<br>**Out:** High-purity 50% aqueous acrylamide solution. |
| **3. Gel polymerization** | Polymerizing the acrylamide solution, with cationic comonomers, into a high-molecular-weight polymer gel. | **In:** Acrylamide solution, comonomers, redox/azo initiators.<br>**Out:** High-viscosity polyacrylamide gel. |
| **4. Granulation and drying** | Shredding the gel and drying it in a fluidized bed without thermal degradation. | **In:** Polymer gel, hot-air dryers.<br>**Out:** Dry polymer crumb. |
| **5. Milling and packaging** | Milling dried crumb into a fine powder and packaging for shipment. | **In:** Dry crumb, hammer mills.<br>**Out:** Packaged flocculant powder. |
| **6. Application and compliance** | Dosing the flocculant in water treatment, mining or papermaking, verified against EPA/REACH monomer limits. | **In:** Flocculant powder, process water/sludge/pulp.<br>**Out:** Clarified water, dewatered sludge, or improved sheet drainage. |

Cross-cutting technologies of the sector:
- **Immobilized nitrile-hydratase biocatalysis:** whole *Rhodococcus rhodochrous* cells, cross-linked and embedded in gel beads, catalyze acrylonitrile-to-acrylamide hydration at controlled low temperature (15-22°C) to prevent both enzyme inactivation and spontaneous monomer polymerization.
- **Adiabatic gel polymerization:** large insulated reactors that rely entirely on the exothermic polymerization reaction's own heat (rising from roughly 10°C to 90°C) to drive the reaction to a high-viscosity, high-molecular-weight polymer gel.
- **Chitosan and cationic-starch natural flocculants:** high-charge-density biopolymers that attract and settle negatively charged colloidal particles (clay, protein, organics) as a biodegradable alternative to synthetic PAM.

---

## US

The US market is shifting toward bio-acrylamide driven by strict EPA limits on residual monomer in drinking water and demand from shale-basin drilling operations.

### EPA residual-monomer limits, shale-basin friction reducers, municipal infrastructure demand
- **Regulatory driver:** EPA's limit on residual acrylamide monomer in treated drinking water (a strong neurotoxin and potential carcinogen at trace levels) has driven demand toward enzymatically produced bio-acrylamide with near-zero unreacted monomer.
- **Shale-basin demand:** oil and gas operations in basins such as the Permian and Bakken consume large volumes of PAM-based friction reducers for hydraulic fracturing, with state environmental requirements pushing operators toward bio-PAM and modified polysaccharides (cationic guar gum, starch derivatives).
- **Municipal infrastructure:** federal grants for municipal wastewater treatment upgrades support procurement of natural-origin cationic flocculants (chitosan-based) for activated-sludge dewatering.

---

## CN

China is the world's largest producer and consumer of acrylamide and polyacrylamide, having shifted its domestic industry to biocatalytic synthesis as part of a national chemical-industry decarbonization program.

### biocatalytic dominance, large-scale environmental applications, starch-graft flocculant development
- **ChemCubic:** manufactures polyacrylamide products for oilfield drilling, enhanced oil recovery and wastewater treatment.
- **Biocatalysis at scale:** Chinese chemical plants have shifted away from older sulfuric-acid and copper-catalyzed acrylamide synthesis toward microbiological synthesis using immobilized *Rhodococcus rhodochrous* cells, eliminating large volumes of toxic copper-bearing wastewater and reducing production energy use.
- **Environmental application scale:** China's municipal wastewater treatment and mine-tailings remediation programs require enormous flocculant volumes, and domestic producers export high-purity bio-acrylamide worldwide.

---

## EU

The EU's REACH regulation and Urban Waste Water Treatment Directive are pushing the flocculant industry toward full biodegradability and biocatalytic production.

### full-biodegradability push, industrial biocatalysis leadership, strict eco-compliance auditing
- **SNF Group:** markets its FLOMIN TFA line of solid-liquid separation aids for mining, spanning high-performance flocculants for thickening, inline flocculation and centrifugation, alongside specialized filtration aids.
- **Kemira:** its Superfloc RH4821 anionic rheology modifier outperformed a previous flocculant in a full-scale tailings-thickening trial at a Brazilian mining site, and its Superfloc BioMB line applies a biomass-balanced approach to polyacrylamide flocculants for sustainable wastewater treatment.
- **Kurita (Kurita Europe):** its Kuriflock Green Technology offers a new generation of biopolymer-based coagulants and flocculants as an alternative to conventional inorganic polymers and fossil-based polyacrylamides, alongside a dedicated PFAS water-treatment portfolio.

---

## Leading companies and research institutes

| Company / Institute | Country | Key products / platforms | Tech features | Status 2026 |
|:---|:---|:---|:---|:---|
| **SNF Group** | 🇫🇷 France | *FLOMIN TFA* mining separation aids | High-performance flocculants for thickening/centrifugation | commercial |
| **Kemira** | 🇫🇮 Finland | *Superfloc RH4821*, *Superfloc BioMB* | Biomass-balanced polyacrylamide, tailings rheology modifiers | commercial |
| **Kurita** | 🇯🇵 Japan | *Kuriflock Green Technology* | Biopolymer coagulants/flocculants, PFAS remediation | commercial |
| **ChemCubic** | 🇨🇳 China | Polyacrylamide for oilfield/EOR | Oilfield drilling and wastewater PAM manufacturing | commercial |

---

## Tech stack and innovations

The biosynthetic acrylamide stack combines enzymatic biocatalysis with large-scale polymer processing:

1. **Immobilized-cell nitrile hydratase biocatalysis:**
   - Whole *Rhodococcus rhodochrous* cells, cross-linked with glutaraldehyde and embedded in polyacrylamide or alginate gel beads, catalyze the hydration of acrylonitrile to acrylamide at greater than 99.9% yield, with a single catalyst charge remaining active for up to 180 days of continuous operation.
2. **Adiabatic gel polymerization reactors:**
   - Large insulated "thermos" reactors polymerize 50% bio-acrylamide solution with cationic comonomers under nitrogen deaeration, relying entirely on the exothermic reaction's own heat to drive polymerization to a dense, elastic gel.
3. **Fluidized-bed drying and milling:**
   - Shredded polymer gel crumb is dried on a multi-zone fluidized-bed belt at controlled temperatures (below 80°C) to avoid thermal crosslinking, then milled to a target particle size for the commercial flocculant powder.

---

## Value chains and production pipelines

### Industrial pipeline for continuous high-purity bio-acrylamide synthesis by enzymatic catalysis

```
┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Producer cultivation &  │ ───> │ 2. Continuous              │
│    biocatalyst prep        │      │    bioconversion reaction  │
└───────────────────────────┘      └───────────────────────────┘
                                                 │
                                                 ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Adiabatic gel           │ <─── │ 3. Biocatalyst separation │
│    polymerization (bio-PAM)│      │    & filtration             │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. Gel shredding, drying   │ ───> │ 6. Standardization,       │
│    & milling                │      │    QA/QC & packaging        │
└───────────────────────────┘      └───────────────────────────┘
```

#### Stage 1: Producer cultivation and biocatalyst preparation
*Rhodococcus rhodochrous* is grown in an aerobic fermenter at 28°C with urea (inducing nitrile hydratase expression) and cobalt salts (a cofactor for the enzyme's active site); harvested cells are cross-linked with dilute glutaraldehyde and encapsulated in polyacrylamide gel beads roughly 1.0-1.5mm in diameter.

#### Stage 2: Continuous bioconversion reaction
Immobilized catalyst beads are loaded into a cascade of 3-4 jacketed tubular reactors; demineralized water and purified acrylonitrile are fed continuously, with feed rate controlled to keep free acrylonitrile below 1.0% (excess substrate denatures the enzyme), while circulating brine holds the reaction at 18-20°C.

#### Stage 3: Biocatalyst separation and filtration
The clear 50% aqueous acrylamide solution exiting the reactor cascade passes through slotted screens that retain and recycle catalyst beads, then through activated-carbon columns to remove trace colored bacterial metabolites, yielding a polymerization-ready clear solution.

#### Stage 4: Adiabatic gel polymerization
The 50% bio-acrylamide is mixed with a cationic comonomer to a 35% total monomer concentration, treated with EDTA to chelate trace metal ions that could terminate chain growth, deaerated with high-purity nitrogen, and pumped into an insulated reactor where a redox/azo initiator system triggers polymerization, with the exothermic reaction driving the mix into a dense elastic gel.

#### Stage 5: Gel shredding, drying and milling
The finished gel block is extruded and shredded with a protective oil emulsion to prevent re-agglomeration, dried on a multi-zone fluidized-bed belt at controlled temperature to avoid thermal crosslinking, and milled to a target particle size in a hammer mill.

#### Stage 6: Standardization, QA/QC and packaging
Dried powder is tested for intrinsic viscosity (to calculate molecular weight, targeting 15+ million Daltons for premium flocculants) and residual free acrylamide monomer by HPLC, then packaged in moisture-barrier polypropylene bags for shipment.