Pulp bleaching with xylanase enzyme pre-bleaching and ECF/TCF processes (oxygen, peroxide, ozone) — instead of elemental chlorine bleaching; with biological effluent treatment

Replaces: elemental chlorine and hypochlorite bleaching · Scope: pulp and paper industry · Evidence: high

The chemical problem#

Bleaching pulp with elemental chlorine creates chlorinated organics (AOX), including dioxins and furans, which were found in fish downstream of mills in the 1980s. In Russia, the Baikalsk Pulp and Paper Mill (operated 1966–2013) discharged effluents into Lake Baikal, a UNESCO World Heritage Site. It became a symbol of industrial pollution and was finally closed in 2013; its sludge ponds remain a remediation challenge.

Product overview#

1. Xylanase pre-bleaching (discovered in Finland at VTT; industrial since the early 1990s): hemicellulose-degrading enzymes open the pulp structure so that lignin is removed more easily, which cuts chlorine chemical demand by about 10–25 % (or boosts TCF brightness). It is used in many mills worldwide.
2. ECF (elemental chlorine free) bleaching with chlorine dioxide: the global standard, greatly reducing dioxins.
3. TCF (totally chlorine free): oxygen delignification, hydrogen peroxide, ozone. Common in the Nordic countries and for sensitive markets.
4. Biological effluent treatment (activated sludge, aerated lagoons, anaerobic reactors) to remove COD and remaining AOX.
5. Laccase-mediator systems (research/pilot) for further delignification.

Active ingredient / Composition#

Xylanases (endo-1,4-β-xylanases from fermentation), oxygen, hydrogen peroxide, ozone, chlorine dioxide (in ECF).

Key facts#

Advantages#

• Drastic reduction of dioxins and AOX.
• Lower chemical costs (xylanase).
• Market access to eco-labelled paper (FSC/EU Ecolabel/Nordic Swan require low AOX).

Mode of action#

Xylanases hydrolyse reprecipitated xylan on fibre surfaces, which improves the accessibility of residual lignin to bleaching chemicals. Oxygen, peroxide and ozone oxidize lignin without chlorination.

Application#

Limitations#

• TCF may give lower brightness and strength for some grades.
• ECF still uses chlorine dioxide (much less problematic than Cl₂, but still forms some AOX).
• Enzyme stages need pH and temperature control.

Evidence of displacement — D1: works, adoption not proven#

Assessment (hand-reviewed): Old process displaced by chemistry: ECF (chlorine dioxide) bleaching is >80% of world bleached pulp (CPI); the enzyme share is not shown.

Figures found (verified as quoted, but the assessment above explains why they do not count as displacement evidence for this substitution):

• displacement — Elemental chlorine-free (ECF) bleaching has become the main method for pulp bleaching and currently accounts for over 80% of the world production of bleached pulp. (global, current; industry association: thecpi.org.uk)
• displacement — In the United States, 90% of active mills had completely switched to ECF by 2002. (USA, 2002; government or intergovernmental: epa.gov)
• displacement — In Japan, about 90% of bleached pulp is produced by ECF bleaching. (Japan, 2012; peer-reviewed: exa.ai)
• displacement — In the United States, ECF bleaching accounted for approximately 33% of BCP production in 1994, rising to 57% in 1998. (United States, 1994-1998; weak: eucalyptus.com.br)

Suppliers — real products and services (from the vendor index)#

Companies below are active vendors in the vendor index whose own card (profile / official website) shows this product or service — matched 2026-09-28 by keyword and checked by hand against the card text. Being listed is not an endorsement; open each card for evidence, contacts and status.

Government funding signals#

Public grants for a specific technology are a leading indicator: governments fund what regulators want to replace and what is close to practical adoption. Searched on 2026-09-27 in: EU CORDIS (FP7, Horizon 2020, Horizon Europe), US federal awards (USAspending: USDA NIFA/ARS/APHIS/Forest Service, EPA, DOE, NOAA, USAID; plus NSF and NIH), UK UKRI Gateway to Research, Australian Research Council. Each grant below was reviewed by hand for relevance. China, Brazil and India are covered in the subsection below (publication-acknowledged grants). Not covered: Russia (RSF, FASIE — not reachable from the research environment) and national agencies outside these databases. Amounts are the funder’s contribution as recorded (US NIH/UKRI: per award or fiscal year).

Signal: Moderate. 1 relevant grant(s) · about €3.3M in total · jurisdictions: EU.

China, Brazil, India — national research grants acknowledged in publications#

Chinese, Brazilian and Indian funders have no open grant databases reachable here, so this measures scientific papers published since 2015 that acknowledge national government grants, taken from the grant numbers publishers deposit with Crossref. Only papers whose title contains this article’s key terms are counted (a conservative lower bound; “100+” = search window full). It shows research-funding intensity, not budgets. Funders: China — NSFC, National Key R&D Program, China Agriculture Research System; Brazil — CNPq, CAPES, FAPESP, Embrapa, FAPEMIG; India — DBT, DST, ICAR, SERB, CSIR, BIRAC. Rating per country: Strong ≥50 papers · Moderate 10–49 · Weak 1–9.

Scientific evidence#

• Viikari L, Kantelinen A, Sundquist J, Linko M (1994). Xylanases in bleaching: from an idea to the industry. FEMS Microbiology Reviews 13: 335–350.
• Bajpai P (2004). Biological bleaching of chemical pulps. Critical Reviews in Biotechnology 24: 1–58.
• Pokhrel D, Viraraghavan T (2004). Treatment of pulp and paper mill wastewater — a review. Science of the Total Environment 333: 37–58.

Bioeconomy value#

Enzymes and oxygen chemistry make the forest-fibre industry cleaner, a central part of the forest bioeconomy, and are relevant to Russian pulp mills near sensitive waters.