碩士 / 國立海洋大學 / 食品科學系 / 89 / Marine biofouling bacterium Klebsiella oxytoca CF154 was cultured in the OMSB broth with the addition of substratum such as activated carbon flake (ACF), small wood coupon, polyethylene (PP) bead, polypropylene (PE) bead, fiber-reinforced plastic (FRP) coupon, chitin flake, glass bead, stainless steel bead, or aluminum bead. After the shaking incubation at 26oC for 48 hr, cell surface hydrophobicity of strain CF154 in stationary phase would be increased with the increase of incubation time (except for the group with chitin flake used). The adhesion of strain CF154 to substratum was positively correlated with the cell surface hydrophobicity, especially on the ACF (R2＝0.96-0.99). The same positive correlation was observed while strain CF154 being cultured in broth uncontrolled pH or controlled at pH 7.2 with various substrata employed in a 5.0 L fermenter (R2＝0.80-0.98).
As to the effect on the increasing extracellular adhesive substratum (EAS) yield of strain CF154 by the addition of adsorptive substratum, only ACF and chitin flake performed significantly higher EAS yield than that of the control group. The EAS yields of ACF, chitin flake, and control group obtained from strain CF154 in shaking incubation were 2.58 g/L, 2.31 g/L and 2.21 g/L, respectively. To understand the EAS production in a stirring and aerating fermenter, the results showed that in the uncontrolled pH incubation group, the EAS yield after 72 hr could reach 3.05 g/L. And while the pH of the cultivation broth was controlled at 7.2, the EAS yield of strain CF154 was raised to the higher yield as 3.78 g/L. In addition, as the pH of the broth was maintained at 7.2, the addition of ACF and chitin flake could raised the EAS yield of strain CF154 to 4.88 g/L and 4.48 g/L, respectively.
During the shaking incubation of strain CF154 in a 250 mL Erlenmeyer flasks, this EAS product could be harvested from the centrifuged pellet (82.2%) and centrifuging supernatant. After strain CF154 was incubated in a aerated fermenter for 24 hr, 42% of the total EAS yield could be recovered from the centrifuged pellet and 58% of the total EAS yield could be obtained from the centrifuging supernatant. In the same incubation system, after
48 hr incubation, 83% of the EAS yield could be separated directly from the centrifuging supernatant, ie., it was present as free EAS. This phenomenon could be deduced that a part of cell capsule material was constantly blended into the broth by impellers of the fermenter.
The composition of EAS powder from strain CF154 had no significant difference from that obtained from culturing in 250 mL Erlenmeyer flasks as well as culturing under uncontrolled pH or controlled pH 7.2 in 5.0 L fermenter. The main component of EAS powder was carbohydrate which contained 76.02-80.35%, and them followed were protein, moisture and ash. 0.2% EAS solution was analyzed by gel permeation chromatography (GPC) of Sephacryl S-400, the results from a series of fractionation demonstrated that mostly of the EAS was the complex of polysaccharide and protein.
| Identifer | oai:union.ndltd.org:TW/089NTOU0253027 |
| Date | January 2001 |
| Creators | WEN CHING MEI, 溫晴美 |
| Contributors | Chorng-Liang Pan, Ph. D,, 潘崇良 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 99 |
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