| Summary: | 碩士 === 元智大學 === 生物科技暨生物資訊研究所 === 95 === In this study we used Vibrio sp. M11 to produce biodegradable polymer, Polyhydroxybutyrate(PHB). In order to enhance PHB production, some investigations including medium optimization, growth conditions and fermentative strategy were carried out. The optimal semi-defined MGYT medium was determined as follows: 10 g/L glycerol, 2 g/L yeast extract, 2.5 g/L tryptone, 28 g/L NaCl through the flask test with various concentrations to each component, and PHB content and PHB concentration were 39.58 % and 1.9 g/L, respectively. The research demonstrated that PHB production, metabolism and synthesis would be effected due to elements addition. After adding(Na2HPO4,KH2PO4, (NH4 )2HPO4, MgSO4 ∙7H2O) elements in optimal semi-defined MGYT medium, CDW would be improved from 4.81 g/L to 8.14 g/L, PHB content reduces by 39.58 % to 1.58 %, and the pH value increases by 4.5 to 6.8. It was speculated that elements induced intracelluar depolymerase expression and PHB granules would be degraded for cell growth. Meanwhile, by residual glycerol analysis, glycerol can be to tally consumpted in 12 hr incubation. Therefore elements addition can easily enchance Vibrio sp. M11 to uptake carbon source and increases cell growth, but not easy to produce PHB. In order to know effects of the ion, therefore individually removes sole ion and increase sole ion carries on the discussion. By results mentioned above we found that when nutrition of culture medium is insufficiency, it is not easy for PHB production. Therefore this research wants to solve this problem using the fermentation strategy. For fed-batch fermentation strategy, the use of feeding medium with the C/N ratio at 4:1 lead CDW to 20.13 g/L and PHB content to 38.25 % even the culture medium contained elements. This results shown that sufficient carbon source and suitable nitrogen limitation facilitated PHB accumulation and prevented PHB degradation.
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