碩士 / 國立高雄海洋科技大學 / 水產食品科學研究所 / 96 / This study investigated the microbial strains with extracellular agar-degrading enzyme (ADE) isolated from the gastrointestinal tracts of locally cultivated abalones. We found that four strains, namely KMU04, KMU06, KMU07 and KMU14, can utilize agar as the sole carbon source. The 3,5-Dinitrosalicylic acid (DNS) colorimetric method was used to measure the amount of reducing sugar in the culture medium containing agar. KUM14 showed the highest specific activity among four strains; therefore, KUM14 was selected to conduct subsequent experiments for ADE production. We found that KUM14 belonged to Vibrio sp. and its optimum growth temperature, pH and salinity ranged between 30~35 ℃, 7~9 and 1~3 %, respectively. After the culture supernatants containing KMU14 ADE were consequently concentrated, precipitated by ammonium sulfate, dialyzed, and fractionated by DEAE column, the fraction V was carried out to the ADE zymogram by SDS-PAGE (containing 0.1% agarose). A clear zone on the gel with a molecular mass of roughly 120 kDa was observed after staining with the Lugol's solution. Thin-layer chromatography (TLC) analysis demonstrated that the fraction V was able to digest agar, agarose, neoagarohexaose, neoagarotetrose, or neoagarobiose into oligosaccharides. In order to optimize the production of KMU14 ADE and further scale up this fermentation procedure, a statistical RSM (response surface methodology) method with central composite design (CCD) was employed. KMU14 was firstly conducted with bottle-swerving tests for its incubation condition optimization. The optimized incubation temperature (℃), salinity (%), agar concentration (%), and air/medium (v/v) ratio were 34 ℃, 1.75 %, 0.35 % and 8, respectively. Furthermore, KMU14 was incubated in a 5 L fully-automatic fermentor under the conditions as the mentioned above and the effects of continuous aeration (0.5~2 vvm) and agitation (50~150 rpm) on its ADE productivity were studied. The results indicated that the optimum aeration and agitation for KMU14 ADE production in the 5 L fermentor were 1vvm and 150 rpm, respectively. In addition, the hydrolysates of seaweed Gracilaria Tenuistipitata obtained by the KMU14 culture supernatant hydrolysis showed noticeable antioxidant activities including DPPH radical scavenging and lipid preoxidation inhibition.
| Identifer | oai:union.ndltd.org:TW/096NKIM8084008 |
| Date | January 2008 |
| Creators | Jian-Wei Ciou, 邱建緯 |
| Contributors | Jing-Iong Yang, 楊景雍 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 106 |
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