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Xylanase XynG1-1 Expression In Pichia And Textile Applications

Posted on:2018-08-09Degree:MasterType:Thesis
Country:ChinaCandidate:T T WangFull Text:PDF
GTID:2321330518993046Subject:Light industry technology and engineering
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Xylan is the main hemicellulolytic polysaccharide found in plant cell wall. Xylanase has been attracted considerable research interest in recent years. It is widely used in pulp and paper industry, food, textile, animal feed, and so on. It mainly exists in the microorganism, protozoa, crustaceans, and tissues of land plants. In view of the low production and stability of xylanase produced by microorganisms,in this study,xylanase encoding gene G1-1 from Paenibacillus campinasensis successfully integrated into genome of Pichia pastoris GS115. The expression of recombinant xylanase, fermentation condition optimization, enzymology properties tests and application to textile process have been studied in this paper. The main results as follows.(1) Gene XynG1-1 was amplificated from the original strain Paenibacillus campinasensis G1-1 and inserted into plasmid pPIC9K between EcoR Ⅰ and Not Ⅰ. The fermentated conditions of the engineering bacteria have been optimized by the response surface method.(2) The recombinant engineering strain was induced, activity of xylanase enzyme was 89.5 IU/mL. Optimal temperature 55 ℃, and optimal pH 6.5. Residual enzyme activities of recombinant xylanase remained 50% after 50 min at 55 ℃, and with excellent stability in the pH 6.5. Suitable for the application of textile industry.(3) The response surface method reached optimize culture conditions of fermentation, yeast powder 20 g/L, peptone 20 g/L, YNB 30 g/L, biotin 4 mg/L, 2.3% final concentration of methanol, culture volume 100 mL, incubate 37.3 h, speed of 250 r/min, temperature of 28℃ and phosphate buffer pH 6.0. It has been verified by experiments that the extracellular enzyme activity of recombinant xylanase cultured under the optimized condition reached at 707.2 IU/mL.(4) In addition, the recombinant strain produced by 10 L fermentation tank with the optimized. The enzyme activity of recombinant xylanase was 2703 IU/mL, the molecular mass is 41 kD.(5) The recombinant xylanase enzyme was used in the process of removing the cotton seed hull of textile processing. Cold heap experimental process, the adding amount of xylanase is 6 g/L, the cotton seed shellis processing time for 14 h removal rate is the largest. Long car experiments show that the amount of adding xylanase is 4 g/L, the cotton seed shellis when handling time of 1 h removal rate tends to be stable. It shew significant improvement of cotton seed hull removal rate. The compound of amylase, pectinase and recombinant xylanase shows the best effect.
Keywords/Search Tags:Pichia pastoris, xylanase, response surface, optimization of fermentation, enzymatic properties, cotton seed hull, removal rate
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