| Summary: | 碩士 === 元智大學 === 生物科技與工程研究所 === 96 === Vibrio spp. M20 a marine bacterium isolated from marine sediment was used to produce biodegradable polymer poly(3-hydroxybutyrate, P(3HB)). In order to enhance P(3HB) production, fascinating investigations including medium optimization, growth criteria under various conditions and fermentative strategies were carried out. A maximum P(3HB) content of about 50% were obtained when using glycerol as the sole carbon source. Gradually the extraction chemicals such as NaOH, NH4OH and NaOCl showed efficient digestion of non PHB cellular materials (NPCM). Also digestion with NaOCl results in 38% P(3HB) in MGYT media and NH4OH results in 31% (P3HB) in MGYTT media, while considering the digestion time length 40 min at 50℃ showed the best fit for extraction. Interestingly when the pH gets reduced it induces the depolymerase enzyme which results in intracellular P(3HB) degradation, this phenomenon has been speculated from adding mineral salts individually, followed by using the sodium citrate buffer at low pH 5.5 resulting in degradation of P(3HB) which leads to decrease of P(3HB) content from 12.3 % to 8.2 % in MGYT and 24% to 6% in MGYTT nearly 4 fold times. This experimental study also shows efficient carbon source, nitrogen source and sodium chloride concentration which facilitates P(3HB) accumulation. Simultaneously effect of individual addition of mineral salts on degradation of P(3HB) content has also been analyzed.
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