Dissertation > Excellent graduate degree dissertation topics show

Characterization of Laccase from Leptographium Qinlingensis Associated with Dendroctonus Armandi

Author: WangLe
Tutor: ChenHui
School: Northwest University of Science and Technology
Course: Forest Protection
Keywords: Leptographium qinlingensis laccase culture condition enzymatic properties laccase gene fragment
CLC: S763.7
Type: Master's thesis
Year: 2011
Downloads: 30
Quote: 0
Read: Download Dissertation

Abstract


The effect of different culture conditions on laccase activity of Leptographium qinlingensis was studied. The laccase derived from L. qinlingensis was purified and characterized in enzymology. Meanwhile, DNA of L. qinlingensis was extracted, and laccase gene fragment was obtained by PCR. The laccase gene fragment was sequenced and analysised.1. The effect of different culture conditions on the laccase activity of L. qinlingensis was investigated by single-factor experiment. The results shown that laccase activity of L. qinlingensis were significantly increased by maltose （as carbon source） and yeast （as nitrogen source）. The laccase activity was induced by copper ions that reached 292.36 IU/L under the medium containing 0.6 mM Cu2+, however, the laccase activity was inhibited by copper ions exceeding 0.9 mM. Furthermore, the laccase activity was induced by phloem powder of host trees （Pinus armandi Fr.）. The peak of laccase activity occurred at the 11th day. The results showed that different culture conditions have remarkable effect on laccase activity of L. qinlingensis. The maximum laccase activity was 681.82 IU/L in the medium containing maltose as carbon source, yeast as nitrogen source, 0.6 mM Cu2+ and 6 g/L phloem powder of host trees at the 11th day.2. The crude enzyme with laccase of L. qinlingensis was concentrated by dialyzing and was purified by DEAE-cellulose （DE-52） chromatographic column （1.6 cm×26 cm）. The high-activity laccase was obtained from the elution liquor. The results showed that the laccase activity was 5209.38 IU/L, the specific activity of laccase was 193.84 IU/mg, and the enzymic purity increases 25.63 fold.3. It was studied that the laccase optimal reaction temperature, the laccase thermal stability, the laccase optimal reaction pH, and the laccase pH stability. The variance analysis of the effect of different metal ions on laccase activity was carried on with the software SAS （V8.1）. The results revealed that the laccase residual activity reached 90% at 35℃to 45℃, and the laccase reaction did not fit in the condition of high-temperature. The laccase is stable at 25℃to 45℃, and the higher the temperature and the longer the stay warm, the less stable the laccase. The laccase of L. qinlingensis optimal reaction pH is 4.4, the further pH get to 4.4, the lower the laccase activity. The laccase is stable in a pH range from 3.6 to 4.4. 1 mM Cu2+ or 1 mM Mg2+ was no significantly influence for the laccase activity, however, 10 mM Cu2+ or 10 mM Mg2+ was extremely significant influence on the laccase activity. Besides, both 1 mM and 10 mM Co2+、Mn2+、Ca2+、Na+、Fe2+ were extremely significant influence on the laccase activity.4. DNA of L. qinlingensis was extracted by improved CTAB method, and laccase gene fragment was obtained by PCR. The laccase gene fragment was sequenced and analysised. A comparison of the nucleotide sequences of the aim fragment and the reported laccase gene in GenBank was carried out by Blastn. The nucleotide sequences of the aim fragment and laccase gene nucleotide sequences of others reported 6 fungi strains were analyzed by ClustalX 2.0.10. The evolutionary tree of 7 fungi strains was drawn. Indicated that the aim fragment was closely related to Calocera viscose （EU882517.1） and Trichoderma hamatum （FJ040333.1）, and was far related to Inocybe （EU88251.1）, Penicillium chrysogenum （XM 002567796.1）, Aspergillus niger （XM0013892）, Nectria （XM 003046649.1）. Most of the fungi of high similarity with the aim fragment were found in rotten wood and plant residues, so it is relative to lignin degradation.

Related Dissertations

  1. Mutagenesis of a Laccase Gene from Pleurotus eryngii in Vitro and Expression in Pichia Pastoris,TQ925
  2. Biochemical Characterization and Molecular Modification of a Novel Marine Mud-derived Pyrethroid Hydrolase,X172
  3. Expression of a Laccase Gene from Lentinula Edodes in Pichia Pastoris and Degradation of Triarylmethane Dyes by Laccase in the Presence of Natural Mediators,TQ925
  4. Research Congo red dye wastewater resin immobilized laccase and its degradation,X791
  5. Characterization, Pharmacodynamics and Bio-security Research of Fibrinolytic Enzyme from Urechis Unicinctus,R96
  6. Study on Laccase Catalyzed Oxidation of Phenolic Compounds in Non-Aqueous Media and Anti-Oxidation Activity of Its End Products,Q814
  7. Degradation of Methyl Orange over Laccase Immobilized of Fe3O4/SiO2 Magnetic Support,X703
  8. Grisea MoIAP apoptosis inhibitory protein gene functional analysis and Bcl-2 spot on the water banana peanut pathogen Fusarium impact,S435.111.4
  9. Biodegradation Research of Nitrogen Heterocyclic Compounds in Simulating Soil by White Rot Fungi,X172
  10. Laccase catalyzed oxidation 17α- ethinyl estradiol experimental study,X50
  11. Preliminary Studies on Decolorization or Degradation of Triphenylmethane Dyes and Bamboo Alkali Lignin by Ligninolytic Enzymes,X703
  12. Dissertation for Master’s Degree Fujian Agriculture and Forestry University,S646
  13. The Amino-Modification on the Surface of Magnetic Fe2O4/SiO2 Support and the Immobilization of Laccase on IT,Q814
  14. Magnetic carbon nanotubes to build and microbial laccase fixed sensor technology research,Q813
  15. Optimum Fermentation Conditions for Lignin Degrading Enzymes of Bamboo Lignin Degradation Fungus,TQ925
  16. Breeding of High-yielding Laccase Strain and Research of Bamboo Lignocellulose Degradation,S795
  17. The Research on Laccase of Myrothecium Melanosporum,TQ925
  18. Selective Enumeration of Mixture and Ferment Milk of Kinds of Lactic Acid Bacteria,TQ921.3
  19. Electrochemical Sensor and Its Application in the Production of the Laccase from Penicillium Simplicissimum Isolated from Composting,TQ440.7
  20. Investigation of Microbial Diversity and Metagenomic Analysis of Ligninolytic Genes for a Tropical Rain Forest Soil from Xishuangbanna,S714.3
  21. The Research of the Construction of the Dorm Culture of the College Students,G641

CLC: > Agricultural Sciences > Forestry > Forest Protection > Forest Pest and Disease Control > All kinds of tree pests and diseases and their prevention
© 2012 www.DissertationTopic.Net  Mobile