| In my master study. I have done two projects using Neurospora crassa as working system, the first was characterization three cellobiose transporters, the second project was the cellulases fermentation media optimization.There are multiple saceharides were generated after the plant biomass degradation by microbes, these saceharides go into the cell by sugar transporters, to be metabolize further in the cell. The transportation is necessary for those carbohydrate matabolism in the nature. The research for non-glucose sugar transporters, especially cellobiose transporter was very little. Neurospora crassa has the cability of cellulose degradation, alcohol fermentation, xylose utilization and so on. It was a great model for filamentous study and has potential industrial application after engineering in the future. In2010, the scientist have cloned cellobiose transporter CDT1、CDT2from Neurospora crassa for the first time, the publications show these two transporters could be very useful for biofuel, but the detgail functions of these transporters in Neurospora crassa was far away understood.This study focued on the three cellobiose/cellodextrin transporters, CDT1CDT2and CDT3, I have constructed the strains of these transporters single, double and triple knock outs, and measured the phenotypes of these strains includes growth, cellulases production, xylanases production and so on. The triple knock out T123strain growth was less than the D12strain in cellobiose culture medium.1have also shown these transporters were localized into cell membrane by GFP-labeled protein.In the second part of my thesis, I have optimized the cellulases fermentation media of N.crassa FGSC2489using the Response Surface Methodology (RSM). Based on the optimized medium, we have significantly improved the cellulases production near2folds, from0.64FPU to1.27FPU. CMC activity production near2.88folds, xylan enzyme activity production near1.86folds, glucosidase activity production near2.08folds. |
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