Effectiveness Assessment of Bio-Enzymatic Alternatives to Acid Washing (Updated April 2025)
- Multi-dimensional analysis of environmental friendliness, efficiency and commercial viability -
1. Core benefits of bio-enzymatic alternatives to acid washing
Typical enzyme preparations:
Cellulase (for cotton/linen):
strips fibers of the Indigo dye on the surface layer, producing a frost white effect (similar to stonewashing but finer).
Laccase: oxidizes the dye molecules, especially suitable for “chlorine-free bleaching” of denim.
Protease (for silk/wool): gentle removal of impurities, alternative to acid etching.
2. Technical bottlenecks in practical applications
Despite the promising future of bio-enzymes, the industry will still face the following challenges in 2025:
Cost:
Enzymes are 3-5 times more expensive than chemicals (e.g., laccase ~￥1200/kg vs. sodium hypochlorite ￥5/kg).
The need for precise pH/temperature control equipment (±0.5 accuracy) makes it difficult for small and medium-sized factories to retrofit.
Limitations:
Difficult to realize the “heavily aged” style of pickling (e.g. cat's whiskers, holes need to be combined with laser or hand).
Less effective on synthetic fibers (polyester/nylon), relies on genetically engineered improved enzymes (e.g. PET hydrolase).
Process stability:
Enzyme activity is greatly affected by water quality (e.g. calcium and magnesium ions inhibit reaction), need to add stabilizers (e.g. glycerol).
3. Industry solutions and innovation cases
① Compound enzyme synergistic technology (such as ZARA's “Eco-Stone” process):
Cellulase + xylanase mixed treatment, so that the cotton fiber microfibrillation, shorten the stone grinding time by 50%.
The fineness of the finished product is increased by 20%, which meets the OEKO-TEX® Class I baby grade standard.
