碩士 / 國立海洋大學 / 食品科學系 / 87 / Abstract
There are thirteen marine bacteria, which isolated from biofouling material of coupons that immersed into sea water, have the capability to hydrolyze agar. These agarase producing strains are belong to Aeromonas salmonicida Aga06、Aga08 and MAEF108, Flavobacterium meingosepticum YBC11A2，Moraxella spp. Aga14 and MAEF102, Pasteurella pneumotropica SCC21, Pseudomonas vesicularis B05, B10, MA103, MAEF103 and YBC12. And strain B13 has not been exclusively identified as the results of inconsistency between traditional and API 20 NE methods, and it is temporally designated as Flavobacterium spp. B13.
The effect of agarase production from Moraxella spp. Aga14, Flavobacterium spp. B13, Pseudomonas vesicularis MA103, and Aeromonas salmonicida MAEF108 were studied on the cultural conditions such as initial pH value, shaking speed, and incubation temperature as well as the composition of cultural medium such as the addition of agar, various nitrogen source, and various metal ions. The experimental results showed the addition of 0.05% NH4NO3 in the basal medium is as found to reach the highest agarase activity for Moraxella spp. For Flavobacterium spp. B13, basal medium containing 1 mM MnCl2.reached the highest agarase activity (13.94 unit). And, the addition of 0.1% yeast extract in the basal medium is required for the highest agarase production for P. vesicularis MA103 (15.73 unit agarase activity). Also, a higher shaking speed employed in the incubation for A. salmonicida MAEF108 at 26oC, the agarase activity of its cultured broth could reach 14.55 unit. By using the combination of individual optimal cultural conditions and components of medium, the agarase production of strain MAEF108 could reach 71.35 unit agarase activity after 24 hr shaking incubation (240 rpm). Then, the agarase production was lower to 59.98 unit as the incubation period extended to 48 hr.
The optimal temperature and pH value of the agarase (primary purified by UF) derived from Moraxella spp. Aga14, Flavobacterium spp. B13, and Pseudomonas vesicularis MA103 are 48oC/8.0, 45oC/6.0, and 45oC/6.0, respectively. For these agarases, then thermal stability at 30oC and stored at -70oC (for 60 days), showed higher stability than stored at -20 and 4oC on the enzymatic activity.
The polysaccharide distributions of the extracts obtained from Gracilaria, enzyme treated Gracilaria, Monostroma, Porphyra, or Porphyra are broad, indicating the nature of heterogeneous polysaccharides. These five algal extracts append only one or two peaks of protein components on the gel permeation chromatograms with a molecular weight ranged from 8.0 103 to 7.0 105 Da. These five algal extracts were also treated by agarase from Pseudomonas vesicularis MA103 for 72, 144, and 216 hr. The protein distributions of these agarase digests were similar to that of untreated algal extracts. As digesting time increased, higher sugar contents present in the late gel permeation chromatograms elution (60-80 fractions) also increased in these five algal extracts.
As the 60-80 fractions of gel permeation chromatogram elutions of these five algal extracts were collected and concentrated, mono- and oligosaccharide compositions were analyzed by an analytical NH2 HPLC column. The chromatogram indicated that D-galactose, 3,6-anhydro-galactose, and several oligosaccharides were present detected. More study was necessary before the identification of these oligosaccharides is completed.
| Identifer | oai:union.ndltd.org:TW/087NTOU0253027 |
| Date | January 1999 |
| Creators | Wu Shao-Chi, 吳紹祺 |
| Contributors | Pan Chorng-Liang, 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 | 177 |
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