Preparation Of Modified Corn Affinity Adsorbents And Its Adsorption Behavior For Proteins

Proteins are the material basis of life, no proteins, no life. The peoples, therefore,have more and more studies for the proteins, and the separation and purification ofvarious proteins have become an arduous and onerous task in biochemistry. Thenatural biomass-corncob were selected as the research object in this paper. Its surfacecontains rich functional groups such as hydroxyl and so on. It was easily cross-linkedand modified. It has wider sources, and it is easy and cheap to get it in ourcountry,which can reduce the cost of the preparation of adsorbents. However, as akind of bio-organisms,corncob has poor adsorption selectivity, regeneration and otherproblems.Many literatures had reported some ways such as acidification,basification,or other simple physical and chemical methods to improve the adsorptionperformance of corncob, but the results are not satisfactory. To solve above problems,based on the corncob as raw material, after cross-linking, modification, and chelatingwith different metal ions, a new batch of adsorbents was prepared. The adsorptionperformance of the biosorbents for lysozyme, bovine serum albumin, catalase hasbeen studied. Specific works are as follows:1、 After pro-treating corncob, Cu（II） chelate affinity adsorbents weresuccessfully prepared with corn cellulose as support, with epichlorohydrin（EPI） ascross-linking agent, iminodiacetic acid（IDA） as modification agent and copper ion aschelate agent. A novel adsorbent was characterized with FTIR, XPS and othermethods. Lysozyme, bovine serum albumin, catalase were selected as adsorptionobject. A series of experiments of adsorption and desorption （including acidity ofsolution, initial concentration of proteins., ionic strength, etc.） was investigated.Results show that the optimal adsorption conditions of the adsorbents for lysozymewere obtained. When the solution acidity is at pH11.0, the adsorption temperature andcontact time are kept at25℃and for12h, respectively, and the maximumadsorption capacity is308.7mg.g^-1.The adsorption process of Cu（II） chelate affinityadsorbents for Lysozyme fitted the Langmuir monolayer adsorption model（R²>0.99）.The theoretical maximum adsorption capacity is307.6mg.g^-1. The metal chelating adsorbents were used to extract lysozyme from egg white. The desorption ofLysozyme was achieved by using1.0mol.L-1NaSCN（pH8.0）as eluent,the elution ratewas96.6%with purification fold28.6. The optimal adsorption conditions ofadsorbents for bovine serum albumin are obtained, When the solution acidity is atpH7.0, the adsorption temperature and contact time are kept at25℃and for12h,respectively, and the maximum adsorption capacity is71.03mg.g^-1. The optimaladsorption conditions of adsorbents for catalase were discussed. The results indicatedthat at pH6.5, and25℃, the adsorption equilibrium can be reached for24h. Themaximum adsorption capacity is120.3mg.g^-1. The adsorption process of Cu（II）chelate affinity adsorbents for catalase fitted the Freundlich multilayer adsorptionmodel（R²>0.98）. The metal chelating adsorbents are used to extract catalase frompig myocardial. The desorption of the catalase was achieved by using1.0mol.L-1NaSCN（pH9.0）as eluent, the elution rate was52.85%with purification fold8.6.2、Zn（II） chelate affinity adsorbents were successfully prepared with corncellulose as support, with epichlorohydrin（EPI） as cross-linking agent, iminodiaceticacid（IDA） as modification agent and zinc ion as chelate agent. Lysozyme, bovineserum albumin, catalase were selected as adsorption object. A series of experiments ofadsorption and desorption was studied. The experimental results show that the optimaladsorption conditions of the adsorbents for lysozyme are following: pH9.9,25℃and for2h. The maximum adsorption capacity is346.9.6mg.g^-1.The adsorptionprocess of Zn（II） chelate affinity adsorbents for Lysozyme fitted the Langmuirmonolayer adsorption model（R²>0.99）. The metal chelating adsorbents are used toextract lysozyme from egg white. The desorption of Lysozyme was achieved by using1.0mol.L-1NaSCN （pH8.0）as eluent,the elution rate was91.9%with purification foldof26.6. The optimal adsorption conditions of the adsorbents for bovine serumalbumin were obtained.When the solution acidity is at pH3.0, the adsorptiontemperature and contact time are kept at25℃and for10h, respectively, and themaximum adsorption capacity is121.3mg.g^-1.The optimal adsorption conditions of the adsorbents for catalase were obtained. The results show that at pH8.0and25℃,the adsorption equilibrium can be reached for24h. The maximum adsorptioncapacity is30.4mg.g^-1. The adsorption process of Zn（II） chelate affinity adsorbentsfor catalase fitted the Langmuir monolayer adsorption model（R²>0.98）,The metalchelating affinity adsorbents are used to extract catalase from pig myocardia. Thedesorption of the catalase was achieved by using1.0mol.L-1NaSCN（pH9.0）as eluent,the elution rate was66.9%with purification fold10.3.3、Fe（II） chelate affinity adsorbents were successfully prepared with corncellulose as support, with epichlorohydrin（EPI） as cross-linking agent, iminodiaceticacid（IDA） as modification agent and iron ion as chelate agent. Lysozyme, bovineserum albumin, catalase selected as adsorption object. A series of experiments ofadsorption and desorption（including acidity of solution, initial concentration ofproteins., ionic strength, etc.） was studied.The experimental results show that theoptimal adsorption conditions of the adsorbents for lysozyme are following: pH8.5,25℃and for4h. The maximum adsorption capacity is283.1mg.g^-1.The adsorptionprocess of Fe（II） chelate affinity adsorbents for Lysozyme fitted the Langmuirmonolayer adsorption model（R²>0.99）. The theoretical maximum adsorptioncapacity is282.2mg.g^-1. The metal chelating adsorbents were used to extractlysozyme from egg white, The desorption of Lysozyme was achieved by using1.0mol.L-1NaSCN（pH7.0）as eluent, the elution rate was87.8%with purification fold33.5. The optimal adsorption conditions of the adsorbents for bovine serum albuminare discussed. When the solution acidity is at pH3.0, the adsorption temperature andtime are kept at25℃and for12h, respectively, and the maximum adsorptioncapacity is99.4mg.g^-1.The optimal adsorption conditions of the adsorbents forcatalase are following: pH7.0,25℃and for24h, and the maximum adsorptioncapacity is139.9mg.g^-1. The adsorption process of Fe（II） chelate affinity adsorbentsfor catalase fitted the Freundlich multilayer adsorption model（R²>0.98）.The metalchelating affinity adsorbents were used to extract catalase from pig myocardial.Thedesorption of the catalase was achieved by using1.0mol. L-1NaSCN （pH9.0）aseluent, the elution rate was55.9%with purification fold12.1. 4、 Ni（II） chelate affinity adsorbents were successfully prepared with corncellulose as support, with epichlorohydrin（EPI） as cross-linking agent, iminodiaceticacid（IDA） as modification agent and nickel ion as chelate agent. Lysozyme, bovineserum albumin, catalase selected as adsorption object. A series of experiments ofadsorption and desorption（including acidity of solution, initial concentration ofproteins., ionic strength, etc.） was investigated.The experimental results show that theoptimal adsorption conditions of the adsorbents for lysozyme are following: pH10.0,25℃and for8h,. The maximum adsorption capacity is280.9mg.g^-1.Theadsorption process of Ni（II） chelate affinity adsorbents for Lysozyme fitted theLangmuir monolayer adsorption model（R²>0.99）. The theoretical maximumadsorption capacity is279.0mg.g^-1. The metal chelating adsorbents were used toextract lysozyme from egg white,The desorption of Lysozyme was achieved by using1.0mol. L-1NaSCN（pH7.0）as eluent,the elution rate was88.1%with purificationfold of14.3. The optimal adsorption conditions of the adsorbents for bovine serumalbumin are discussed. When the solution acidity is at pH3.0, the adsorptiontemperature and contact time are kept at25℃and for12h, the maximum adsorptioncapacity is69.0mg.g^-1.The optimal adsorption conditions of adsorbents for catalaseare following: pH8.0,25℃and for24h. and the maximum adsorption capacity is21.5mg.g^-1. The adsorption process of Ni（II） chelate affinity adsorbents for catalasefitted the Langmuir monolayer adsorption model（R²>0.91）. The metal chelatingaffinity adsorbents were used to extract catalase from pig myocardial,The desorptionof the catalase was achieved by using1.0mol. L-1NaSCN（pH9.0）as eluent, theelution rate was75.4%with purification fold14.9.