Thermal Stabilizer Of Amylase And Steam Desizing Process Of Cotton Fabric

Cotton fabric is liked extensively as a clothing material due to its hygroscopicity,fabric breathability,comfort and reasonable in price,and also used in room's decoration and industry.The desizing process of cotton fabric among textile industry is paid close attention to.Cotton fabric will be damaged during tradition pretreatment,which can also cause pollution.From the mid-20th century on,α-amylase was investigated as a bio-desizing agent in enzyme desizing process of cotton fabric due to enzyme's high efficient,specificity,ecological and mild treatment condition.α-amylase consists two kinds,they are mesophilic enzymes and thermophilic enzymes. amylase is a protein,so heat inactivation of theα-amylases under high temperature is inevitable, especially mesophilicα-enzymes.In this paper,some thermal stabilizers ofα-amylases were investigated to improve thermostability ofα-enzymes.Thermal stability ofα-amylase was studied,the result is showed that kinetics of thermal inactivation ofα-amylase is followed by first order reaction.Half-life is 6.3min at 60℃and 1.8min at 70℃,the amylase could not be used in high temperature.Thermal stabilizers were selected.The result is showed that calcium acetate,sodium lactate, chitosan and L-histidine could be used to improve thermal stability ofα-amylase in the paper.First three thermal stabilizers play a great role in improving thermal stability at higher temperature, half-life is increased to 637.8min,470.4min,more than 912.4min at 70℃under optimum concentration.Half-life ofα-amylase with L-histidine is 420.4min at 60℃under optimum concentration.Cotton fabric is also a good thermal stabilizer ofα-amylase.Half-life is 47.3min at 90℃and 15.5min at 100℃.Cotton fabric with chitosan play a better role than cotton fabric,half-life ofα-amylase with chitosan on cotton fabric is 108.7min at 90℃and 23.1min at 100℃.Soα-amylase steam desizing process at 100℃of cotton fabric is possible.The concentration of chitosan was studied as a process condition.Single factors experiment and orthogonal experiment was studied to optimize process conditions.The result showed that desizing ratio is affected by the concentration ofα-amylase,the concentration of chitosan, desizing time,pick up,temperature and pH value.So orthogonal experiment of L₁₆(4⁵) was designed to get the better process conditions.The desizing process conditions:steaming temperature 100℃,pH=6,α-amylase 1g/L,chitosan 0.75g/L,steaming time 15min,desizing ratio is 98.6%.