TL;DR
- Neutral cellulase can replace much of the pumice abrasion in a denim wash. The risk is that the same enzyme that fades and softens the surface will keep cutting cotton cellulose if dose, time and stopping are not controlled.
- Strength is protected by three levers: the dose (% on weight of garment, owg), the contact time, and a hard stop of enzyme activity at the end of the cycle.
- Our neutral denim grades list a dose of 0.1–0.3% owg with 45–60 minutes for two grades. Another lists 0.2–0.3% owg for 45–90 minutes. A higher-dose grade lists 0.5–1.5% owg for 20–40 minutes. Dose is not comparable between grades without checking each grade’s activity and unit definition.
- The reaction can be stopped by holding the bath above 80 °C for 10 minutes or above pH 8.0 for 10 minutes. This is the practical brake on over-hydrolysis.
- No tensile or tear-strength figures are published in our product data. Strength retention has to be measured in your own trial on your own fabric.
How do you get stone-wash fading without losing fabric strength?
Denim makers want the worn, faded, soft look that stone-wash (pumice) processing used to give. Pumice and acid washes are the general industry alternatives; our product data does not document their machine wear, residue, or effluent impact, so no comparison to them is made here. Neutral cellulase does the abrasion chemically at the fibre surface, so the aim is a controlled, superficial attack.
The trade-off is that cellulase works on the same polymer that gives cotton its strength. Our product data states the goal — “designed to enzymatically abrade denim without harming the fabric” — and lists “optimum strength retention” as a benefit for V999 and A6, without publishing tensile or tear numbers. The risk that pushing dose, time or stop too far keeps cutting cellulose and weakens fabric is general enzymology, not a line from our data, and is the reason a stop step matters. So the process question is how to stop at the surface.
Buyers also want this without adding steps or upsetting the existing dye and wash workflow. Our neutral grades list an active pH range (5.5–7.5 for N-3000, 5.0–7.0 for TM600); the data does not state how much, if any, re-buffering a normal wash bath needs, so confirm that in your own trial.
How does neutral cellulase act on denim?
Cellulose is a glucose polymer linked by β-1,4-glycosidic bonds. Our cellulase data describes a three-part system: endoglucanase (random internal cuts), cellobiohydrolase (works from chain ends, releasing cellobiose) and β-glucosidase (splits cellobiose into glucose). These act together on cellulose.
For denim, the useful action is at the fabric surface, where fibre ends and the dyed outer layer are most accessible. Mechanical action in the machine, plus the enzyme, removes weakened surface material and exposes lighter fibre beneath — the abrasion and fading effect, a softer hand, and less fuzz.
The same product data also names cotton, hemp, viscose, yarn and lyocell as fibres N-3000, TM600 and V999 can be used on (not stated for A6). Regenerated cellulosics such as viscose and lyocell are generally more accessible to enzyme than cotton, so they need their own trial rather than reuse of a cotton recipe. That is general industry knowledge, not one of our product specs.
Which operating variables control the outcome?
The data for our neutral denim grades gives the following. Figures are per grade, as published.
| Grade | Declared activity | Temperature | pH | Liquor ratio | Dose (owg) | Time |
|---|---|---|---|---|---|---|
| N-3000 powder | 4,000 u/g | Active 20–70 °C, optimum 40–60 °C | Active 5.5–7.5, optimum 6.0–7.0 | 5:1–20:1 | 0.1–0.3% | 45–60 min |
| TM600 granulate | 1,700 u/g | Active 40–60 °C, optimum 50 °C | Active 5.0–7.0, optimum 5.0–6.0 | 5:1–20:1 | 0.1–0.3% | 45–60 min |
| V999 powder | 2,000 u/g | Not published | Not published | 5:1–20:1 | 0.2–0.3% | 45–90 min |
| Deni WT A6 | ≥4,000 u/g | ”Wide range” (no figures in text) | Not published in text | 7:1–10:1 | 0.5–1.5% | 20–40 min |
Points to read carefully:
- Units. One unit is the amount of enzyme that releases 1 µg of reducing sugar (as glucose) from CMC-Na per minute at 50 °C and pH 6.0. Our feed cellulases use a different definition (1 µmol, 37 °C, pH 5.5) — do not compare u/g across families.
- Dose. Because activity, unit and recommended dose differ, a higher u/g number does not simply mean a lower dose. Start from each grade’s own published range.
- Liquor ratio. Bath volume affects mechanical action and enzyme concentration. Keep it fixed during a dose trial so you change one variable at a time.
- pH and temperature. Staying inside the optimum window gives predictable speed; drifting out slows the reaction. That is not a safe way to control strength, since the drift is uncontrolled.
- No per-grade time-versus-strength curve. Find the time at which your target fade is reached and treat any time beyond that as pure risk.
How do you stop the enzyme once the look is right?
This is the most direct control over over-hydrolysis. The product data for the neutral grades states that holding the bath above 80 °C for 10 minutes, or above pH 8.0 for 10 minutes, completely inactivates the enzyme.
In practice, build the stop into the recipe rather than relying on rinse dilution: a defined temperature or pH shift at the end of the contact time, verified by a bath check, and logged. A wash that carries active enzyme into a later stage keeps working on the garments. Slight sedimentation in the stored product is described as acceptable and does not affect performance, so it is not a reason to change dose.
Limitations and trade-offs
- Strength is the cost of overdosing. Our product pages for V999 and A6 list “optimum strength retention”, and the general cellulase pages list “higher strength of fabric” with no comparison to any other process. These are qualitative statements. No tensile, tear or weight-loss numbers are published in our data, so do not plan a specification on them.
- Back staining. In general process terms, cellulase abrasion can release indigo that redeposits on the garment — that mechanism is not stated in our product data. What the data does state is that the A6, V999 and TM600 pages list low back staining or good anti-back-staining as a benefit. Confirm on your shade and your wash sequence, especially at higher dose or longer time.
- Pumice replacement is not always total. The data describes replacing pumice for a worn look. Heavy distressing may still need some mechanical help. Trial to see what your target style needs.
- Fabric variation. Weave, weight, finishing history and prior treatments change enzyme access. A recipe from one fabric is a starting point only.
- Storage. N-3000, TM600 and A6 each list a 9-month shelf life in a dry, cool place, sealed and out of direct sunlight, with slight sedimentation described as acceptable; the V999 record supplied here does not carry this detail. Old stock may need a rate re-check, so track receipt dates.
- Handling. Enzyme preparations are proteins that can sensitise susceptible people and irritate skin, eyes or nasal mucosa. Avoid direct skin contact and dust generation, and follow your site’s handling procedure.
How to design a trial that proves strength retention
Run a controlled comparison rather than switching the production line.
- Fix the baseline. One fabric lot, one garment style, one machine, one liquor ratio, plus a control lot on your current method.
- Dose ladder. Test at least three doses inside the grade’s published range (low, mid, high). Hold time and temperature constant.
- Time ladder. At the chosen dose, test two or three contact times inside the published window.
- Hard stop. Apply the same inactivation step to every run, then confirm it.
- Measure. Fade, surface cleanliness, hand feel, back staining, weight loss, and tensile/tear strength against unwashed and control-washed fabric, warp and weft.
- Choose the lowest dose and shortest time that meet the fade target with acceptable strength, then repeat on a second lot to confirm reproducibility.
Because strength values are not in our data, this measured comparison is the only reliable evidence of retention.
Product fit: sourcing cellulase
Enzymes.bio is a supplier and trader of enzymes, not a manufacturer. For denim, the relevant grades in our listing are:
- Cellulase Enzyme Powder for Stone Washing Process (Conzyme® N-3000, CAS 9012-54-8): neutral, 4,000 u/g, optimum pH 6.0–7.0 and 40–60 °C.
- Neutral Cellulase for Textile Industry in Denim Washing Process (Conzyme® TM600): granulate, 1,700 u/g, optimum pH 5.0–6.0 at 50 °C.
- Neutral Cellulase Powder for Denim Fabric Garment Washing (Conzyme® V999): 2,000 u/g, 0.2–0.3% owg.
- Neutral Cellulase Enzyme for Efficient Denim Abrasion (Conzyme® Deni WT A6, CAS 9012-54-8): ≥4,000 u/g, 0.5–1.5% owg, 20–40 minutes.
N-3000, TM600 and A6 are supplied in 1 kg bags (not stated in the V999 record supplied here). Separately, our acid cellulase powder (CAS 9012-54-8, 11,000 u/g, pH 4.5–6.0) is listed for bio-polishing at acid pH. Its data gives no denim dose, so it is a different route rather than a substitute for the neutral grades above.
To compare grades for your fabric and wash equipment, see the range on the cellulase enzyme hub and request trial quantities.
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