The Research Of Thermal Stability And The Kinetic Of Thermal Deactivation In α-Amylase With The Addition Of Auxiliaries

Bio-enzymes were widely used for textile processing in recent years due to their characteristics such as high efficiency,high specificity and mild processing condition as well as eco-friendly.a-amylase faced many challenges because it had short half-life and it was easily deactivated at improper temperature.The addition of auxiliaries to a-amylase was a convenient and effective method to make it.lt was researched that the effect on the enzyme activity and the optimum temperature of a-amylase with the addition of various metallic ions, alcohols, carbohydr-ate and polyethylene glycol.lt was investigated that the kinetic of thermal deactivation and the effect of auxiliaries on the kinetic of thermal deactivation in a-amylase.By means of single factor experiments and orthogonality experiments,the optimum conditions were obtained.Firstly,it was researched that the effect on the enzyme activity and the optimum temperature of a-amylase with the addition of various metallic ions,alcohols,carbohydrate and polyethylene glycol.The results demonstrated that lmmol/L K+ improved the relatively enzyme activity to 109.56%;250mmol/L D-sorbierite improved the relatively enzyme activity to 108.71%; 50 mmol/L glycerine improved the relatively enzyme activity to 109.08%;250mmol/L glucose improved the relatively enzyme activity to 108.81%;250mmol/L trehalose improved the relatively enzyme activity to 108.84%.To compare withα-amylase,the optimum temperature ofα-amylase with K+,D-sorbierite, glycerine, glucose and trehalose rised respectively from 60℃to 80℃,85℃,85℃,85℃,90℃.Secondly,it was investigated that the kinetic of thermal deactivation and the effect of auxiliaries on the kinetic of thermal deactivation inα-amylase.The results demonstrated the kinetic of thermal deactivation inα-amylase accords with first-order reaction dynamic model.lts thermal stability was poorer compared with the addition of auxiliaries toα-amylase.70℃,with the addition of KCl,half-life ofα-amylase rised from the original 3min to 900min;with the addition of D-sorbierite,half-life ofα-amylase increased to 910min;with the addition of glycerine,half-life ofα-amylase increased to 920min;with the addition of glucose,half-life ofα-amylase increased to 1000min;with the addition of trehalose,half-life ofα-amylase increased to 1200min.75℃,with the addition of trehalose,half-life ofα-amylase increased to 900min.80℃,with the addition of trehalose,half-life ofα-amylase increased to 400min.85℃,with the addition of trehalose,half-life ofα-amylase increased to 350min.90℃,with the addition of trehalose,half-life ofα-amylase increased to 100min.So,trehalose was the best heat stabilizer.To compare withα-amylase,the energy ofα-amylase with K+,D-sorbierite, glycerine, glucose and trehalose rised respectively from the original 128.78kJ/mol to 172.34kJ/mol,175.34kJ/mol,175.89kJ/mol,178.65kJ/mol,178.99 kJ/mol.Finally,by means of single factor experiments and orthogonality experiments,desizing process conditions including trehalose concentration,α-amylase concentration,batching temperatu-re&time,pH value and JFC content in treating cotton fabrics withα-amylase in the exist of trehalose were discussed and the optimum conditions were obtained.The optimum conditions in single factor experiments:trehalose concentration 750mmol/L,a-amylase concentration 3g/L, batching temperature 75℃,batching time 1h,pH value 6.3 and JFC content 1g/L.It was revealed that after adding 750mmol/L, trehalose inα-amylase,the desizing percentage reached to 97.4%,batching temperature rised by 10℃and batching time shortened by 1h.Inα-amylase treating cotton fabric by itself,the desizing percentage reached to 94.55%.Compared with onlyα-amylase in desizing,the addition of trehalose effectively improved desizing percentage and saved energy.