In our first part of this series we explored how paper, one of humanity’s oldest inventions, remains vital in a digital world. But the story doesn’t end there — it turns a new page when biology steps into the mill. In this article, the narrative shifts from steam and steel to cells and enzymes.
With biosolutions taking the center stage, it’s the story of how an industry once defined by heavy machinery and chemical use began learning from the lightest touch in nature.
From its first known sheets in China, paper has played an indispensable role in human life, and for almost 1,800 years, the possible environmental and health impacts of its production went largely unnoticed.
By the 1980s, however, the pulp and paper industry faced growing scrutiny, as researchers began uncovering a concerning outcome of wood-based, large-scale paper production:
Highly toxic chemicals, known as dioxins, were appearing in rivers, fish, and even everyday products like diapers 1,3,5 — posing serious health risks, including cancer, reproductive disorders, and immune system damage. In 19872, the U.S. Environmental Protection Agency confirmed elevated dioxin levels downstream from pulp and paper mills, while in Sweden, fish in the Gulf of Bothnia showed skeletal deformities4.
One major source of concern was the use of elemental chlorine in bleaching. While cheap and effective, it reacted with wood’s natural compounds, producing toxic byproducts such as dioxins and furans, another harmful class of chemicals. Governments imposed stricter environmental standards, but global paper demand — already 61 million tonnes annually6 — did not pause. The industry turned to alternative chemical bleaching methods, including elemental chlorine free (ECF) with chlorine dioxide, and total chlorine free (TCF) using hydrogen peroxide or ozone, though these often affected paper quality.
As mills searched for a cleaner, affordable way to make high-quality paper, a solution emerged from an unexpected place: biology.
Researchers discovered that naturally occurring enzymes — particularly xylanase — could pre-bleach wood pulp. By breaking down natural carbohydrate bonds in the fibers, the enzyme allowed mills to achieve the same brightness with far less chemical bleach, dramatically reducing dioxin formation.
It was a small biological intervention but it marked the beginning of something much larger: The pulp and paper industry had taken its first step into a new era, one where nature itself began helping to make an industrial process less demanding on the planet.
The idea of using biology to make cleaner paper sounded revolutionary, but in practice it was anything but simple.
As enzymes are natural products (proteins), they do not perform well under high heat, pressure, or extreme pH levels — and the papermaking process is anything but mild. After wood is turned into pulp and ready for bleaching, the temperature of the pulp is around 100°C (212°F) and the pH level is about 107,8. This creates a very harsh environment for an enzyme.
(You’ll remember that pH is a measure of how acidic or alkaline a solution is. A pH of 7 sits right in the middle — neutral, like water. Anything below 7 is acidic, like lemon juice, and anything above 7 is alkaline, like soap).
This mismatch posed a major challenge for bringing enzymes into papermaking. To make them work, mills would have had to modify their process — cooling the pulp, adjusting the pH, and then reheating it for further processing — all of which meant more time, higher costs, and extra wastewater. Worse, these interruptions risked affecting paper quality. For an operation designed to run continuously, it was like asking a locomotive to stop for a tea break.
By all logic, the idea of using enzymes in papermaking should have been shelved. Instead, it became the start of a quiet revolution.
As biotechnology advanced through the late 1980s and early 1990s, scientists began exploring enzymes from microbes that thrived in extreme environments — places where heat, alkalinity, and pressure were part of daily life. Step by step, they learned how to make enzymes sturdier, more reliable, and better suited for industrial conditions. Pioneers, including those at Novonesis, developed enzymes that could tolerate and survive the intense conditions created during the papermaking process.
Now, biology could keep pace with industry. These new enzymes fit naturally into the existing process. Mills no longer had to redesign equipment or add extra steps to accommodate enzymes. It was more than a scientific breakthrough; it marked a shift in mindset.
Today, enzymes have made their way into nearly every stage of papermaking, resulting in improved paper quality, reduced energy use, and lowering the environmental impact of pulp and paper.
Let’s further explore how enzymes help in papermaking with some examples.
We already learned that xylanase helped make bleaching safer and cleaner. But how does this enzyme actually do its job?
To turn wood chips into paper, they are cooked in large, pressurized vessels called digesters, where heat and chemicals break down lignin — the tough natural glue that gives wood its strength and brown color. Most lignin is removed, leaving soft pulp, but some remains, trapped inside xylan, a gluey coating that even strong bleaches struggle to penetrate.
Traditionally, mills used extra chlorine dioxide to break through this barrier, but this was costly and created more chemical waste. Xylanase offers a better solution. Added before bleaching, it breaks down the xylan coating, exposing the remaining lignin so chlorine dioxide can work efficiently. Industrial trials show xylanase pre-bleaching can cut chlorine dioxide use by up to 30 percent9 while improving paper brightness. This reduces chemical, energy, and water consumption — and shields mills from volatile bleaching chemical costs, which make up nearly 17 percent of production10.
The xylanase used by the pulp and paper industry now can tolerate temperatures close to 90°C (194°F) and alkaline pH levels near 10 without losing activity11. This means they fit right into existing operations; no new equipment, no major process changes, just better performance for the mills including lower overall energy use and carbon emissions. A tiny biological actor, but one that continues to make a big difference — for both paper and the planet.
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After bleaching, the pulp is a mass of long fibers — stiff, smooth, and stubborn. Left alone, they barely stick together. To make strong paper, these fibers need to fray into tiny, hair-like strands called fibrils. The more fibrils, the more contact points, and the stronger the sheet.
Traditionally, mills relied on massive machines to do the job — pounding fibers into shape with brute force. It worked, but at a cost: huge energy use and frequent fiber damage. Then came cellulase, a quiet biological hero. This enzyme gently softens the fiber’s surface, making fibril formation easier and the refining process far gentler. The result: smoother control, less energy use, and stronger paper. One European mill using cellulase cut refining energy by half while boosting paper strength by 16%12.
Cellulase also enables more efficient use of fillers like calcium carbonate, which improve smoothness and brightness. By enhancing fiber bonding, mills can add up to 20% filler without weakening the paper13, stretching each tree’s potential.
While some enzymes strengthen fibers, others keep machines clean and running smoothly — quietly solving some of papermaking’s toughest operational headaches.
If you’ve ever scrubbed a greasy pan, you have a sense of what papermakers face — only their “pan” is a massive paper machine, often over 100 meters (300 feet) long, churning out hundreds of tonnes of paper every day.
A constant challenge inside these machines is sticky deposits. There are two main types: pitch and stickies. Pitch comes from the wood itself — natural resins and fats released during pulping that coat metal surfaces and build up over time12. Stickies, on the other hand, come from recycled paper — labels, tape, and adhesives that melt during processing and create stubborn, sticky contaminants12.
For decades, mills relied on harsh chemicals, acids, and dispersants to control these deposits, at the cost of energy, frequent shutdowns, and polluted wastewater12. Enzymes have changed that:
Lipase breaks down the fatty components of pitch into smaller, harmless compounds that either wash away with the pulp or lose their stickiness, while esterase targets synthetic stickies, neutralizing their tackiness12. Together, they allow paper machines to run longer between cleanings, improve paper quality, and reduce reliance on harsh chemical treatments12.
Alongside xylanase and cellulase, these enzymes enable mills to work smarter, cleaner, and more sustainably than ever12, 13. Other enzymes, such as alpha-amylase and laccase, have quietly joined the process, addressing starch and lignin residues. These newcomers illustrate how the enzyme palette is broadening, offering more precise, sustainable ways to tackle a wider range of challenges.
From a modest beginning in the 1980s, when the first xylanases offered a cleaner way to bleach pulp, enzymes have quietly reshaped the world of papermaking. What began as a response to an environmental challenge has evolved into a powerful industrial advantage.
Today, enzymes reduce chemical use, save energy, strengthen fibers, and improve recycling efficiency — all while maintaining quality. Originally a small experiment, each enzyme brings a touch of precision to a process once ruled by heat and force. These biosolutions are now essential to modern papermaking, pointing to a future where biology continues to inspire innovation.
You’re wearing the same science as your paper
The same enzymes that help make smoother, stronger paper are also working quietly in your laundry detergent. They’re called cellulases — enzymes that act on cellulose, the main building block of both wood and cotton fibers. In paper mills, cellulases gently reshape wood fibers so they bond better and make the paper feel smoother. In your washing machine, they smooth out tiny cotton fibers on clothes by removing fuzz and pills14, keeping fabrics looking fresh and bright15 longer.
Pizza has a papermaking cousin
Believe it or not, the same enzyme that keeps paper machines clean also helps give cheese its mouthwatering flavor. It’s called lipase, an enzyme that breaks down fats through a process called hydrolysis, turning them into free fatty acids. In paper mills, this reaction helps prevent sticky substances like pitch from gumming up the machines. In cheese-making, it is the same reaction — only this time, the milk fats are turned into free fatty acids which give cheese its rich flavors16.
What is common between paper mills, beer, and yoghurt?
Modern paper mills have something in common with your favorite yogurt and beer — microbes and fermentation. The enzymes used in papermaking are made by microbes that grow in giant fermentation tanks, much like the ones used to brew beer or culture yogurt. These tiny organisms naturally produce enzymes like xylanase and cellulase, which help mills make paper more efficiently and sustainably. In both cases — whether it is craft beer or craft paper — the magic happens because microbes do what they do best: ferment, transform, and create.
In our first part of this series we explored how paper, one of humanity’s oldest inventions, remains vital in a digital world.
Microbes and enzymes are tiny but mighty agents of change. For billions of years, they’ve enabled transformation in all living things through microbiology.
Biosolutions are fascinating but can be difficult to grasp. That's why we created the monthly Biosolutions Bulletin — to break down the science into easy-to-understand, engaging stories with beautiful hand-drawn illustrations.
Each issue dives deep into the science behind biosolutions and their roles in transforming everything from agriculture to industries and the products we use every day.
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References
1. Policy Vs. Consumer Pressure: Innovation and Diffusion of Alternative Bleaching Technologies in the Pulp Industry. https://www.nber.org/system/files/working_papers/w13439/w13439.pdf
2. Competitive Implications of Environmental Regulation. A Study of Six lndustries. The Management Institute for Environment and Business and U.S. Environmental Protection Agency. https://www.epa.gov/sites/default/files/2017-12/documents/ee-0045_all.pdf
3. Traces of Dioxin Found in Range Of Paper Goods. https://www.nytimes.com/1987/09/24/us/traces-of-dioxin-found-in-range-of-paper-goods.html
4. Physiological Disturbances in Fish Living in Coastal Water Polluted with Bleached Kraft Pulp Mill Effluents. https://cdnsciencepub.com/doi/10.1139/f88-181
5. Dioxins. Effects on human health. WHO. https://www.who.int/news-room/fact-sheets/detail/dioxins-and-their-effects-on-human-health
6. Pulp and Paper Capacity Survey. FAO. https://www.fao.org/4/aq088t/aq088t00.pdf
7. Pulp Bleaching. https://doi.org/10.1002/0471238961.1621121613030415.a01.pub3
8. Application of Xylanases in the Pulp and Paper Industry. https://www.sciencedirect.com/science/article/abs/pii/0960852494902224
9. Novonesis insights
10. FisherSolve 2025
11. Novonesis slide
12. Unlock the natural strength of paper and board. The clear benefits of FiberCare® - Novonesis Fiber modification
13. Novonesis FiberCare®. More filler, less fiber. Novonesis - Cut production costs in your paper mill
14. Want to put an end to fuzz and pills? Novonesis - Fabric & color care
15. Stop dirt redeposition with cleaning cellulases. Novonesis - Whiteness & brightness
16. Microbial lipases in cheese production: an in-depth review of their role in quality, texture, and flavor. https://pubmed.ncbi.nlm.nih.gov/40886725/