Study On Bio-scouring Technology Of Wool Fiber

Enzymatic scouring technology of woolen fiber was studied in order to reduce theenvironmental pollution and chemical residues caused by wool scouring. Bacillus subtilisand Candida lipolytica were selected for enzymatic production. The fermentation conditionsfor bacillus subtilis were: maltodextrine11.568g/L, corn starch22.462g/L, yeast extract10.202g/L, NaCl5g/L, inoculum2%, liquid volume40mL/250mL flask，initial pH7.0,speed225r/min,37℃cultured for48h，protease activity up to3281.79U/mL；Thefermentation conditions for candida lipolytica were: glucose2.5g/L, peptome5.685g/L,K₂HPO₄5.510g/L, KH₂PO₄2g/L, MgSO₄·7H₂O1g/L, olive oil10g/L, Tween-803g/L，inoculum1%, liquid volume30mL/250mL flask, initial pH7.76, speed180r/min，28℃c ultivated for48h, lipase activity up to211.46U/mL.Enzymatic scouring of woolen fiber was optimized and observed that a better treatingcondition for the enzyme produced by Bacillus subtilis and Candida lipolytica at a ratio of1:4. Plackett-Burman design was used to evaluate the effects of the main factors further.The response surface methodology （RSM） was used to optimize the factors and thequadratic regression model equation was calculated by appropriate statistical methods. Theoptimal parameters of the variables were observed, including enzyme dosage of6%, bathratio at1:33.28, temperature at40.44℃and time for18.11h. Under the optimum conditions,the residual fat content was reduced from1.06%to0.75%, which indicate the responsesurface methodology （RSM） is feasible to optimize the enzymatic scouring of woolen fiber.Compared with the traditional scouring, fiber diameter reduced from23.5μm to23.3μm, theintensity of whiteness increased from58.4to69.7, breaking elongation rate increased from30.82%to32.15%, and breaking strength had no significant changes, but the scouring effectsignificantly improved.In order to elaborate on the enhanced capability of enzyme scouring process from thebiological point of view, the mechanism of biological enzyme scouring and catalyticreaction of protease and lipase was studied, and stated structural changes in wool afterscouring and its impact on fiber performance. The enzyme catalyzed hydrolysis was in solid-liquid phase during enzymatic scouring process, and the principle of dynamics wasdifferent from the traditional enzymatic hydrolysis. As can be seen from scanning electronmicroscopy image analysis, the use of biological enzyme scouring, the woolen fiber surfacecovered by almost no lanolin, wool scales could be clearly seen, so it reachedGB6977-86.To mention further it was observed that the wool’s surface has cracks andmodified tilt scales which indicate the presence of biological enzymes, has etching effectson wool scales, can improve the woolen fiber felting and post-processing effects of wool.