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標題: 交聯型聚合酵素製備方法、特性及固定化應用之評估分析
Evaluation on the preparation, characterization, and application of cross-linked enzyme aggregates for enzymes immobilization
作者: 李易蒼
Lee, I-Tsang
關鍵字: 交聯型聚合酵素;Cross-linked enzyme aggregates;酵素;enzyme
出版社: 化學工程學系所
引用: 1. Suen, S.-Y., Y.-C. Liu, and C.-S. Chang, Exploiting immobilized metal affinity membranes for the isolation or purification of therapeutically relevant species. Journal of Chromatography B, 2003. 797: p. 305–319. 2. Liese, A. and M.V. Filho, Production of fine chemicals using biocatalysis. Current opinion in biotechnology, 1999. 10(6): p. 595 -603. 3. Patel, R.N., Biocatalytic synthesis of intermediates for the synthesis of chiral drug substances. Current opinion in biotechnology, 2001. 12(6): p. 587-604. 4. Huisman, G.W. and D. Gray, Towards novel processes for the fine-chemical and pharmaceutical industries. Current opinion in biotechnology, 2002. 13(4): p. 352-358. 5. Sheldon, R.A., R. Schoevaart, and L.M. Van Langen, Cross-linked enzyme aggregates (CLEAs): A novel and versatile method for enzyme immobilization (a review). Biocatalysis and Biotransformation, 2005. 23(3-4): p. 141-147. 6. Wandrey, C., A. Liese, and D. Kihumbu, Industrial biocatalysis: Past, present, and future. Organic process research & development, 2000. 4(4): p. 286 -290. 7. L´opez-Serrano, P., L. Cao, F.v. Rantwijk, and R.A. Sheldon, Cross-linked enzyme aggregates with enhanced activity: application to lipases. Biotechnology letters, 2002. 24: p. 1379–1383. 8. Schoevaart, R., M.W. Wolbers, M. Golubovic, M. Ottens, A.P.G. Kieboom, F.v. Rantwijk, . . . R.A. Sheldon, Preparation, Optimization, and Structures of Cross-Linked Enzyme Aggregates (CLEAs). Biotechnology and bioengineering, 2004. 87(6): p. 754-762. 9. Cao, L., L.v. Langeny, and R.A. Sheldon, Immobilised enzymes: carrier-bound or carrier-free? Current opinion in biotechnology, 2003. 14(4): p. 387 -394. 10. Mozhaev, V.V., M.V. Sergeeva, A.B. Belova, and Y.L. Khmelnitsky, Multipoint attachment to a support protects enzyme from inactivation by organic solvents: alpha-Chymotrypsin in aqueous solutions of alcohols and diols. Biotechnol Bioeng, 1990. 35(7): p. 653-659. 11. Arnold, F.H., Engineering proteins for nonnatural environments. FASEB J., 1993. 7(9): p. 744-749. 12. Reetz, M.T. and K.-E. Jaeger, Directed Evolution as a Means to Create Enantioselective Enzymes for Use in Organic Chemistry. Directed Molecular Evolution of Proteins, 2002: p. 245-279. 13. Gupta, M.N., Enzyme function in organic solvents. Eur J Biochem, 1992. 203: p. 25-32. 14. Gupta, M.N., Non-aqueous enzymology: issues and perspectives. Methods in Non-Aqueous Enzymology, 2000: p. 1-13. 15. Lee, M.-Y. and J.S. Dordick, Enzyme activation for nonaqueous media. Curr Opin Biotechnol, 2002. 13(4): p. 376-384. 16. Roy, I. and M.N. Gupta, Freeze-drying of proteins: some emerging concerns. Biotechnol Appl Biochem, 2004. 39(2): p. 165-177. 17. Roy, I. and M.N. Gupta, Enzymes in organic media. Forms, functions and applications. Eur J Biochem, 2004. 271(13): p. 2575-2583. 18. Brady, D. and J. Jordaan, Advances in enzyme immobilisation. Biotechnol Lett, 2009. 31: p. 1639-1650. 19. Clair, N.L.S. and M.A. Navia, Cross-linked enzyme crystals as robust biocatalysts. J. Am. Chem. Soc., 1992. 114(18): p. 7314-7316. 20. Partridge, J., P.J. Halling, and B.D. Moore, Practical route to high activity enzyme preparations for synthesis in organic media. Chem. Commun., 1998. 7: p. 841-842. 21. Roy, I. and M.N. Gupta, Preparation of highlyactive α-chymotrypsin for catalysis in organicmedia. Bioorganic & Medicinal Chemistry Letters, 2004. 14(9): p. 2191-2193. 22. Cao, L., F.v. Rantwijk, and R.A. Sheldon, Cross-Linked Enzyme Aggregates:  A Simple and Effective Method for the Immobilization of Penicillin Acylase. Org. Lett., 2000. 2(10): p. 1361-1364. 23. Wilson, L., A. Illanes, O. Romero, J. Vergara, and C. Mateo, Carrier-bound and carrier-free penicillin acylase biocatalysts for the thermodynamically controlled synthesis of β-lactam compounds in organic medium. Enzyme and Microbial Technology, 2008. 43: p. 442-447. 24. Jaeger, K.-E. and M.T. Reetz, Microbial lipases form versatile tools for biotechnology. Trends in Biotechnology, 1998. 16(9): p. 396-403. 25. Wang, A., F. Zhang, F. Chen, M. Wang, H. Li, Z. Zeng, . . . Z. Chen, A facile technique to prepare cross-linked enzyme aggregates using p-benzoquinone as cross-linking agent. Korean J. Chem. Eng, 2011. 28(4): p. 1090-1095. 26. Wilson, L., A.s. Illanes, L. Soler, and M.a.J. Henrı´quez, Effect of the degree of cross-linking on the properties of different CLEAs of penicillin acylase. Process Biochemistry 2009. 44: p. 322-326. 27. Quiocho, F.A. and F.M. Richards, Intermolecular cross linking of a protein in the crystalline state: Carboxypeptidase -A. Proc Natl Acad Sci U S A. , 1964. 52(3): p. 833-839. 28. Margolin, A.L., Novel crystalline catalysts. TIBTECH, 1996. 14: p. 223-230. 29. Lalonde, J., Practical catalysis with enzyme crystals. Chemtech, 1997. 27(2): p. 38-45. 30. Haring, D. and P. Schreier, Cross-linked enzyme crystals. Current Opinion in Chemical Biology, 1999. 3(1): p. 35-38. 31. Margolin, A.L. and M.A. Navia, Protein Crystals as Novel Catalytic Materials. Angew. Chem. Int. Ed., 2001. 40: p. 2204-2222. 32. Brown, D.L. and C.E. Glatz, Aggregatebreakage in protein precipitation. Chemical Engineering Science, 1987. 42(7): p. 1831-1839. 33. Cao, L., L.M.v. Langen, F.v. Rantwijk, and R.A. Sheldon, Cross-linked aggregates of penicillin acylase: robust catalysts for the synthesis of b-lactam antibiotics. Journal of Molecular Catalysis B: Enzymatic, 2001. 11: p. 665-670. 34. Wegman, M.A., M.H.A. Janssen, F.v. Rantwijk, and R.A. Sheldon, Towards Biocatalytic Synthesis of β-Lactam Antibiotics. Advanced Synthesis & Catalysis, 2001. 343(6-7): p. 559-576. 35. Langen, L.M.v., N.H.P. Oosthoek, F.v. Rantwijk, and R.A. Sheldon, Penicillin Acylase Catalysed Synthesis of Ampicillin in Hydrophilic Organic Solvents. Advanced Synthesis & Catalysis, 2003. 345(6-7): p. 797-801. 36. Wilson, L., A. Illanes, O. Abian, B.C.C. Pessela, R. Fernandez-Lafuente, and J.M. Guisan, Co-aggregation of penicillin G acylase and polyionic polymers: An easy methodology to prepare enzyme biocatalysts stable in organic media. Biomacromolecules, 2004. 5(3): p. 852-857. 37. Wilson, L., A. Illanes, B.C.C. Pessela, O. Abian, R. Fernandez-Lafuente, and J.M. Guisan, Encapsulation of crosslinked penicillin G acylase aggregates in lentikats: Evaluation of a novel biocatalyst in organic media. Biotechnology and bioengineering, 2004. 86(5): p. 558-562. 38. Theil, F., Enhancement of Selectivity and Reactivity of Lipases by Additives. Tetrahedron, 2000. 56(19): p. 2905-2919. 39. Shah, S., A. Sharma, and M.N. Gupta, Preparation of cross-linked enzyme aggregates by using bovine serum albumin as a proteic feeder. Analytical Biochemistry, 2006. 351: p. 207–213. 40. 田蔚城, 生物技術的發展與應用. 九州圖書文物有限公司, 1998. 41. 張春生, 生物觸媒--酵素在現代工業所扮演的角色, 2004: 南台科技大學生物科技系會議論文. p. 1-4. 42. Schmid, A., J.S. Dordick, B. Hauer, A. Kiener, M. Wubbolts, and B. Witholt, Industrial biocatalysis today and tomorrow. Nature, 2001. 409(6817): p. 258-268. 43. Chang, C.S. and S.W. Tsai, A facile enzymatic process for the preparation of (s)-Naproxen ester prodrug in organic solvents. Enzyme and Microbial Technology, 1997. 20(8): p. 635-639. 44. Shang, C.S. and C.S. Hsu, Lipase-catalyzed enantioselective esterification of (S)-naproxen hydroxyalkyl ester in organic media. Biotechnology letters, 2003. 25(5): p. 413-416. 45. Sheldon, R.A., Cross-Linked Enzyme Aggregates (CLEAs): An Enabling Technology, 2011: CLEA Technologies. p. 1-7. 46. 陳國誠, 生物固定化技術與產業應用. 茂昌圖書有限公司, 1990: p. 48-57. 47. 潘建亮, 固定化盤尼西林去醯基酵素反應動力學建模及其兩水相系統分離反應之探討2005, 國立成功大學化學工程研究所博士論文. 48. 余焜乾, 固定化酵素N-carbamoyl-D-amino acid amidohydrolase於再生纖維膜上之效率探討2010, 國立中興大學化學工程學系碩士學位論文. 49. 陳國誠, 生物固定化技術與產業應用2000, 茂昌圖書有限公司. 50. Cao, L., L.v. Langeny, and R.A. Sheldon, Immobilised enzymes: carrier-bound or carrier-free? Current Opinion in Biotechnology, 2003. 14: p. 387-394. 51. Tischer, W. and F. Wedekind, Immobilized Enzymes: Methods and Applications. Topics in Current Chemistry, 1999. 200: p. 95-126. 52. 陳怡雯, 含聚乙二醇雙性高分子之製備與其固定化酵素之研究2008, 國立台灣科技大學化學工程系碩士學位論文. 53. Macrae, A.R., Lipase-catalyzed interesterification of oils and fats. Journal of the American Oil Chemists'' Society, 1983. 60(2): p. 291-294. 54. Susumu, O., I. Mieko, and T. Yoshio, Synthesis of various kinds of esters by four microbial lipases. Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1979. 575(1): p. 156-165. 55. Hellyer, S.A., I.C. Chandler, and J.A. Bosley, Can the fatty acid selectivity of plant lipases be predicted from the composition of the seed triglyceride? Biochimica et Biophysica Acta 1999. 1440: p. 215-224. 56. Hasan, F., A.A. Shah, and A. Hameed, Industrial applications of microbial lipases. Enzyme and Microbial Technology, 2006. 39(2): p. 235-251. 57. 曾詩雯, 利用脂解酵素催化動力分割合成 (S)-Naproxen 之 Piperazinylalkyl ester 前驅藥2004, 台南科技大學生物科技研究所碩士學位論文. 58. Sheldon, R.A., Cross-linked enzyme aggregates (CLEA (R) s): stable and recyclable biocatalysts. Biochemical Society Transactions, 2007. 35: p. 1583-1587. 59. Gupta, P., K. Dutt, S. Misra, S. Raghuwanshi, and R.K. Saxena, Characterization of cross-linked immobilized lipase from thermophilic mould Thermomyces lanuginosa using glutaraldehyde. Bioresource Technology, 2009. 100: p. 4074–4076. 60. Gunasekaran, V. and D. Das, Lipase fermentation : Progress and prospects. Indian Journal of Biotechnology, 2005. 4: p. 437-445. 61. 蔡文城, 微生物學, 2002: 藝軒圖書出版社. 62. 王志堅 and 朱夢麟, 盤尼西林抗藥性肺炎雙球菌. 國防醫學, 1995. 第21卷(第3期): p. 179-181. 63. 陳省宏, 電流與電位式量測釕氧化物與盤尼西林酵素修飾電極之研究2006, 國立雲林科技大學電子工程系碩士論文. 64. 張簡志強, 應用金屬親和薄膜分離純化盤尼西林醯胺酵素2003, 國立中興大學化學工程學系碩士論文. 65. Liu, J.G., L. Liang, G.X. Li, R.S. Han, and K.M. Chen, H+ISFET-based biosensor for determination of penicillin G. Biosensors & Bioelectronics, 1998. 13(9): p. 1023-1028. 66. 林宥欣, 以高密度大腸桿菌培養製程量產重組Penicillin Acylase, 2001: 逢甲大學化學工程研究所碩士論文. 67. Rajendhran, J. and P. Gunasekaran, Recent biotechnological interventions for developing improved penicillin G acylases. Journal of Bioscience and Bioengineering, 2004. 97(1): p. 1-13. 68. Migneault, I., C. Dartiguenave, M.J. Bertrand, and K.C. Waldron, Glutaraldehyde: behavior in aqueous solution, reaction with proteins, and application to enzyme crosslinking. Biotechniques, 2004. 37(5): p. 790-802. 69. Zhao, L.F., L.Y. Zheng, G. Gao, F. Ha, and S.G. Cao, Resolution of N-(2-ethyl-6-methylphenyl) alanine via cross-linked aggregates of Pseudomonas sp Lipase. Journal of Molecular Catalysis B-Enzymatic, 2008. 54(1-2): p. 7-12. 70. Kartal, F., M.H.A. Janssen, F. Hollmann, R.A. Sheldon, and A. Kilinc, Improved esterification activity of Candida rugosa lipase in organic solvent by immobilization as Cross-linked enzyme aggregates (CLEAs). Journal of Molecular Catalysis B-Enzymatic, 2011. 71(3-4): p. 85-89. 71. Valdes, E.C., L.W. Soto, and G.A. Arcaya, Influence of the pH of glutaraldehyde and the use of dextran aldehyde on the preparation of cross-linked enzyme aggregates (CLEAs) of lipase from Burkholderia cepacia. Electronic Journal of Biotechnology, 2011. 14(3). 72. Pan, J.A., X.D. Kong, C.X. Li, Q. Ye, J.H. Xu, and T. Imanaka, Crosslinking of enzyme coaggregate with polyethyleneimine: A simple and promising method for preparing stable biocatalyst of Serratia marcescens lipase. Journal of Molecular Catalysis B-Enzymatic, 2011. 68(3-4): p. 256-261. 73. Kim, M., J.M. Park, H.J. Um, D.H. Lee, K.H. Lee, F. Kobayashi, . . . Y.H. Kim, Immobilization of cross-linked lipase aggregates onto magnetic beads for enzymatic degradation of polycaprolactone. Journal of Basic Microbiology, 2010. 50(3): p. 218-226. 74. Hara, P., U. Hanefeld, and L.T. Kanerva, Sol–gels and cross-linked aggregates of lipase PS from Burkholderia cepacia and their application in dry organic solvents. Journal of Molecular Catalysis B: Enzymatic, 2008. 50: p. 80-86. 75. Yan, J.Y., X.H. Gui, G.L. Wang, and Y.J. Yan, Improving Stability and Activity of Cross-linked Enzyme Aggregates Based on Polyethylenimine in Hydrolysis of Fish Oil for Enrichment of Polyunsaturated Fatty Acids. Applied Biochemistry and Biotechnology, 2012. 166(4): p. 925-932. 76. Wilson, L., G. Fernandez-Lorente, R. Fernandez-Lafuente, A. Illanes, J.M. Guisan, and J.M. Palomo, CLEAs of lipases and poly-ionic polymers: A simple way of preparing stable biocatalysts with improved properties. Enzyme and Microbial Technology, 2006. 39(4): p. 750-755. 77. Illanes, A., L. Wilson, C. Altamirano, Z. Cabrera, L. Alvarez, and C. Aguirre, Production of cephalexin in organic medium at high substrate concentrations with CLEA of penicillin acylase and PGA-450. Enzyme and Microbial Technology, 2007. 40(2): p. 195-203. 78. Kilcawley, K.N., M.G. Wilkinson, and P.F. Fox, Determination of key enzyme activities in commercial peptidase and lipase preparations from microbial or animal sources. Enzyme and Microbial Technology, 2002. 31: p. 310-320. 79. Balasingham, K., D. Warburton, P. Dunnill, and M.D. Lilly, The isolation and kinetics of penicillin amidase from Escherichia coli. Biochimica et Biophysica Acta (BBA) - Enzymology, 1972. 276(1): p. 250-256. 80. Rajendhran, J. and P. Gunasekaran, Application of cross-linked enzyme aggregates of Bacillus badius penicillin G acylase for the production of 6-aminopenicillanic acid. Letters in Applied Microbiology, 2007. 44(1): p. 43-49. 81. Yan, J.Y., L.F. Li, Q.L. Tang, M.Z. Jiang, and S.Z. Jiang, Preparation of a Crosslinked Bioimprinted Lipase for Enrichment of Polyunsaturated Fatty Acids from Fish Processing Waste. Applied Biochemistry and Biotechnology, 2010. 162(3): p. 757-765. 82. Shah, S., S. Sharma, and M.N. Gupta, Biodiesel preparation by lipase-catalyzed transesterification of Jatropha oil. Energy & Fuels, 2004. 18(1): p. 154-159. 83. Majumder, A.B., K. Mondal, T.P. Singh, and M.N. Gupta, Designing cross-linked lipase aggregates for optimum performance as biocatalysts. Biocatalysis and Biotransformation, 2008. 26(3): p. 235-242. 84. Mateo, C., J.M. Palomo, L.M. van Langen, F. van Rantwijk, and R.A. Sheldon, A new, mild cross-linking methodology to prepare cross-linked enzyme aggregates. Biotechnology and bioengineering, 2004. 86(3): p. 273-276. 85. Kazan, D., H. Ertan, and A. Erarslan, Stabilization of Escherichia coli penicillin G acylase against thermal inactivation by cross-linking with dextran dialdehyde polymers. Applied Microbiology and Biotechnology, 1997. 48(2): p. 191-197. 86. Devi, B., Z. Guo, and X.B. Xu, Characterization of Cross-Linked Lipase Aggregates. Journal of the American Oil Chemists Society, 2009. 86(7): p. 637-642. 87. Wang, M.F., W. Qi, C.X. Jia, Y.F. Ren, R.X. Su, and Z.M. He, Enhancement of activity of cross-linked enzyme aggregates by a sugar-assisted precipitation strategy: Technical development and molecular mechanism. Journal of Biotechnology, 2011. 156(1): p. 30-38. 88. Yu, H.W., H. Chen, X. Wang, Y.Y. Yang, and C.B. Ching, Cross-linked enzyme aggregates (CLEAs) with controlled particles: Application to Candida rugosa lipase. Journal of Molecular Catalysis B-Enzymatic, 2006. 43(1-4): p. 124-127. 89. Aytar, B.S. and U. Bakir, Preparation of cross-linked tyrosinase aggregates. Process Biochemistry, 2008. 43: p. 125-131. 90. Aguirre, C., M. Toledo, V. Medina, and A. Illanes, Effect of cosolvent and pH on the kinetically controlled synthesis of cephalexin with immobilised penicillin acylase. Process Biochemistry, 2002. 38(3): p. 351-360. 91. Arroyo, M., R. Torres-Guzman, I. De la Mata, M.P. Castillon, and C. Acebal, A kinetic examination of penicillin acylase stability in water-organic solvent systems at different temperatures. Biocatalysis and Biotransformation, 2002. 20(1): p. 53-56. 92. Ulijn, R.V., L. De Martin, P.J. Halling, B.D. Moore, and A.E.M. Janssen, Enzymatic synthesis of beta-lactam antibiotics via direct condensation. Journal of Biotechnology, 2002. 99(3): p. 215-222. 93. Youshko, M.I. and V.K. Svedas, Penicillin acylase-catalyzed solid-state ampicillin synthesis. Advanced Synthesis & Catalysis, 2002. 344(8): p. 894-898. 94. Illanes, A. and A. Fajardo, Kinetically controlled synthesis of ampicillin with immobilized penicillin acylase in the presence of organic cosolvents. Journal of Molecular Catalysis B-Enzymatic, 2001. 11(4-6): p. 587-595. 95. Illanes, A., C. Altamirano, M. Fuentes, F. Zamorano, and C. Aguirre, Synthesis of cephalexin in organic medium at high substrate concentrations and low enzyme to substrate ratio. Journal of Molecular Catalysis B-Enzymatic, 2005. 35(1-3): p. 45-51. 96. Arroyo, M., R. Torres-Guzman, I. de la Mata, M.P. Castillon, and C. Acebal, Activation and stabilization of penicillin V acylase from Streptomyces lavendulae in the presence of glycerol and glycols. Biotechnology Progress, 2000. 16(3): p. 368-371. 97. Tischer, W. and V. Kasche, Immobilized enzymes: crystals or carriers? Trends in Biotechnology, 1999. 17(8): p. 326-335. 98. Pchelintsev, N.A., M.I. Youshko, and V.K. Svedas, A new method for spectrophotometric assay of activity of cross-linked penicillin acylase aggregates. Biochemistry-Moscow, 2006. 71(3): p. 315-319. 99. Tyagi, R., R. Batra, and M.N. Gupta, Amorphous enzyme aggregates: Stability toward heat and aqueousorganic cosolvent mixtures. Enzyme and Microbial Technology, 1999. 24(5-6): p. 348-354.
交聯型聚合酵素(Cross-linked enzyme aggregates;CLEAs)是一種新穎簡單之固定化方法,利用酵素交聯聚合,形成生物催化固體物。此酵素固定化方法具低成本、無載體、易製備、高比活性等優勢。因此本論文整合多篇文獻及相關研究結果,分述兩種酵素PGA (penicillin G acylase)和脂肪酵素(Lipase) 用於製備CLEAs,比較其活性、熱穩定性和重覆使用性的影響,由形態學及動力學參數,評估CLEAs的優劣性,並分析不同製備方法於工業應用上之實用性。

經評估得知,利用Lipase固定在磁性載體Dynabeads® M-270,經過交聯反應形成CLEAs,經30天的存放,仍保有80%殘餘活性;30次循環重複使用後,仍保有超過60%殘餘活性,比一般製備Lipase CLEAs方法,有更高的儲存穩定性和重複使用性。此外,Serratia marcescens lipase (SmL),加polyethyleneimine (PEI),製備CLEA-SmL-GA,在50℃下,經10天培養週期後,仍保留64%殘餘活性,顯示高熱穩定性。

另一方面,評估於工業上較具實用性之PGA CLEAs,PGA在乙二醇中,利用離子聚合物Dextran sulfate(DS)和polyethyleneimine(PEI)共聚集製備而成CLEA-GPD,經過30天的存放後,活性增加超過200%,具高儲存穩定性。在50℃下,添加BSA製備PGA CLEAs,經8小時培養,測得剩餘活性約70%。顯示添加BSA做為交聯型聚合酵素的共聚集,能有效提高熱穩定性。

Cross-linked enzyme aggregates (CLEAs) is a novel and simple process for enzyme immobilization, which generates the solid biocatalyst by cross-linking the enzyme to form aggregate. The merits of CLEAs are low-cost, carrier-free, easy preparation, and high specific activity. This study reviewed a series of relative journals and reports, and collected the preparation approaches of CLEAs for two model enzymes, i.e., PGA (penicillin G acylase) and lipase. The activity, reusability, thermal stability, morphology, and kinetic parameters of these two enzymes were compared. The analysis and applications of CLEAs under different methods were also included.

As shown in the reports, the storage stability and reusability of immobilized lipase on amino-functionalized magnetic supports (Dynabeads® M-270) via cross-linked enzyme aggregates (CLEA) was the highest as compared to other CLEAs preparations, where 80% of its initial activity could be maintained for 30 days’ storage test, and more than 60% of lipase activity could be reserved after 30 times consecutive use. In addition, the polyethyleneimine (PEI) was added to CLEA-SmL-GA of Serratia marcescens lipase was found to possess the best thermal stability at 50 ℃, where 64% of the activity could be retained for 10 days’ test.

On the other hand, the CLEAs preparations for PGA on the industrial applications were reviewed and discussed. The CLEA-GDP, prepared with dextran sulfate (DS) and polyethyleneimine(PEI), gave the highest storage stability. Its activity increased over 200% its original activity for a 30 days’ storage test. PGA CLEAs prepared in the presence of BSA could retain 70% of its original activity for a test at 50℃ for 8 h. From the results, the thermal stability could be effectively improved when using PGA CLEAs prepared with BSA as the co-aggregate cross-linking reaction.
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