Dissertation > Excellent graduate degree dissertation topics show

The Study on the PLD Immobilization by Covalent and Enrich Cross-linking Technologies

Author: ZhaoPengHua
Tutor: ZhangXiaoLi
School: Northwestern University
Course: Biochemical Engineering
Keywords: phospholipase D cellulose covalent immobilization enrich cross-linking method
CLC: Q814.2
Type: Master's thesis
Year: 2009
Downloads: 137
Quote: 3
Read: Download Dissertation

Abstract


Phospholipase D （PLD）, which is also called as phosphatidylcholinase [EC3.1.4.4], plays an important role in catalysing organic alkali group exchange reactions of phospholipids. This kind of reactions can be applied in the phospholipid structure transformation, which is a crucial technology in preparing various semi-sythetic phospholipids. However, there are some difficulties in PLD production, such as low fermentative activity and purification problems. Besides, binary-water phase system is necessary to catalytical reactions of phospholipids. Hence, PLD immobilization calls for more advanced technologies. Covalent immobilization is a promising method, which combines the enzyme and the carrier by covalent bond with a good stability and repetitiveness. In this paper, the study of PLD immobilization was investigated in detail.The PLD immobilization was carried out by the combination with an actived cellulose carrier, which was actived by epichlorohydrin （ECH）. The alkli type and concentration, the ratio between cellulose and ECH, as well as the actived time, which affected the efficiency of PLD immobilization, were invertigaed in this paper. The optimal condition of carrier activation was: 1 mol·L-1 NaOH 20 ml, microcrystalline cellulose 1 g, ECH 4 ml. Further more, immobilization time, temperature, the ratio between carrier and enzyme were also inverstigated. The optimal condition of PLD immobilization was: epoxy cellulose 1 g, PLD solution 30 ml (crude protein 0.8 g·L-1) and the immobilization temperature and time were 37℃and 12 h respectively. In this condition, the immobilization efficiency reached to 48.8%. Compared with the free PLD, the immobilized one had the higher thermal and operational stabilities.In this section, we took glucoamylase in stead of PLD for lower cost. Cellulose, coarse pore silica gel and epoxy-cellulose were taken as enzyme carrier in glucoamylase immobilization. The results showed that the protein loading efficiency can be improved by adding precipitant regardless of carrier types. The PLD immobilization adopted an enrich cross-link method with the cellulose carrier. The optimal condition was as following: the ratio among enzyme solution, carrier and percipitant was 5ml·0.8mg/ml: 1g: 10ml （NH4）2SO4. After absorption of enzyme and the carrier, precipitant and glutaraldehyde were added in to the system at the same time. The initial concentration of glutaraldehyde was 0.12%. The reaction processed by magnetic stirring for 40 min and then added more glutaraldehyde to reach to a concentration of 0.18%. Further reaction was carried out for 30 min in the shaker. At last, immobilized enzyme was acquired after filtering, washing and vacuum. The immobilized enzyme by enrich cross-linking method was very stable and could be preserved for a long time, which was similar with the characters of enzyme immobilized by covalent binding. The immobilized enzyme acquired by this method is difficult to deactive and be affected by mass transfer, which facilitates quality control.

Related Dissertations

  1. The Environmental-Friendly Method and Process of Removing Non-Cellulosic Matters from Bamboo for Textile Fiber,TS652
  2. Distribution of the Contents of Pectin and Cellulose and Their Effect on Smoking Quality in Flue-cured Tobacco of China,S572
  3. Sophorose the extraction and purification for the inter- type Neurospora cellulase produced induction of,TQ925
  4. Preparation of Composite Nanofibers Via Elecrtrospinng,TB383.1
  5. Study on Hydrophobic Modification of Sodium Carboxymethyl Cellulose and Ph-Sensitive Hydrogel,O631.3
  6. Effects of Topical Cyclosporine 0.05% on the TEatment of Dry Eye,R777
  7. Fe 3 O 4 , carbon nanotubes and graphene reinforced regenerated cellulose membrane research,TB383.1
  8. Bacterial cellulose-based acoustic properties of diaphragm materials,TB383.2
  9. Bacterial cellulose supported palladium catalyst for Heck and Suzuki coupling reaction of catalytic properties,O643.32
  10. Effects of GPI-PLD Gene on Invasioness and Vasculogenic Mimicry of the Hepatoma Carcinoma Cell Line HepG2,R735.7
  11. The Association between cPLA2 Genetic Polymorphism and Alzheimer’s Disease in Hunan Han Population of China,R749.16
  12. Study on Bactrial Cellulose Production Using Methanol Wastewater,X783
  13. Modification of cellulose acetate butyrate and UV-curable coatings,TQ630.4
  14. Preparation Method Study of Acetyl Cellulose Aqueous Dispersion,R944
  15. Imidazolium Ionic Liquids in Synthesis and Application of cellulose hydrolysis,TQ353.1
  16. Preparation and Characterization of Fluorescent Comb-copolymers Based on Ethyl Cellulose,O631.3
  17. Hydroxyapatite / nano- cellulose Preparation and characterization of composite materials,R318.08
  18. Screening of Cellulase-Producing Strain and Studies on Fermentation Condition and Characteristics of Enzyme,TQ925
  19. Preparation and Quality Assessment of Roxithromycin-ethylcellulose Microspheres and Tablets,R94
  20. Effect of Phospholipase D Inhibitor Treatment on Postharvest Quality Maintenance of Flat Peach Fruits,S662.1
  21. Secretory Phospholipase A2 and sOX40L Levels and Their Correlations to Severity of Coronary Lesion in Acute Coronary Syndrome,R541.4

CLC: > Biological Sciences > Bioengineering ( Biotechnology ) > Enzyme Engineering > Immobilized enzyme and immobilized cell technology
© 2012 www.DissertationTopic.Net  Mobile