The Study Of Enzymes On Soaking Effect And Inffluencing Faceors

Soaking agent are added in leather soaking process.Most of these soaking agent can cause environmental pollution.Recent years in order to reduce the use of chemical materials environmental that cause environmental pollution in leather soaking process and to solve environmental problems,people put enzyme preparations as soaking agent.In this study,the soaking effects of enzyme were discussed at various conditions including the dosages of alkaline protease,neutral protease and lipase,pH,and concentration.Then,investigating of mass transfer characteristics of protease in soaking process using fluorescence tracing and effect of metal ions on the activity of enzyme.The main contents and results are as follows:(1)Alkaline protease,neutral protease and lipase were used in leather soaking,respectively.And,water absorption is tested.The results show that the three kinds of enzyme preparation can increase the water absorption of leather,reduce the soaking time.Lipase can significantly increase the water absorption at low dosage.With the increase of the concentration,the degree of water absorption changes gradually.Unlike lipase,the water absorption increases with the increase of the amount of protease.When the amount of alkaline protease was 0.7%and the amount of neutral protease was 0.9%,the water absorption capacity reached the maximum.(2)The two proteases were compounded with lipase,respectively.The soaking effects of enzyme were discussed at various conditions including the dosages of alkaline protease,neutral protease and lipase,pH,and concentration.Afterwards,the optimal soaking condition was obtained according to water absorption,protein and hydroxyproline concentration in soaking wastewater,the softness of hide and the extent of yellow streak.The best soaking effect was observed with pH=10,tare weigh ratios of 0.4%and 0.1%for alkaline protease and lipase respectively.(3)Alkaline protease,neutral protease and lipase were first labeled by using fluorescein isothiocyanate(FITC),then they were used in leather soaking.They were accurately observed using fluorescence microscope that trypsin transfers to the middle layer of the pelt through both grain and flesh side at asimilar rate,and alkaline protease and neutral protease could fully penetrate into the pelt in 6h and 4h respectively.While lipase penetrate into the pelt in 1.5h.(4)The effects of Ca2+,Mg2+and K+ on the activity of alkaline protease were investigated.The results show that when Ca2+ concentration was lower than 4mmol/L,the activity of alkaline protease was activated.When Ca2+ concentration was higher than 4mmol/L,the activity was inhibited.Mg2+ has an activating effect on alkaline protease activity but K+inhibits alkaline protease activity.