Isolation of pseudoalteromonas agarovorans and optimization of saccharification

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To obtain the strain for effective saccharification of alginate, a number of marine bacteria were isolated from seawater in Korea. Among ten strains, the strain CHO-33 was selected, because it exhibited the high saccharification yield. In order to identify the isolated strain CHO-33, the biochemical and physiological characteristics were determined. The cell was round-shaped, Gram-negative, motile, and strictly aerobic. Growth occurs in media containing 1-8% of NaCl and temperature ranging from 5-38oC. The strain CHO-33 could utilize D-glucose, maltose, and D-mannitol but it does not utilize D-fructose, mannose, sucrose, and glycogen. In addition, this strain was sensitivity to carbenicillin, tetracycline, ampicillin, and streptomycin. In order to perform the phylogenetic analysis, the 16s rDNA of the strain cho-33 was amplified by PCR. The lengths of the almost complete 16 rDNA gene sequences of strain CHO-33 was 1,439 bp. The 16s rDNA gene sequences of the related taxa were obtained from GeneBank. Phylogenetic analysis based on 16S rDNA gene sequences indicated that the strains CHO-33 is similar to the type strains of belong to Pseudoalteromonas sp., indicating that the strain CHO-33 is member of the genus Pseudoalteromonas The strain CHO-33 was found to form a coherent cluster with the type strain of Pseudoalteromonas agarovorans (98.4%), P. atlantica X82134 (97.3%), P. espejiana X82143 (97.1%), P carrageenovora X82136 (96.8%), P. tetraodonis X82139 (96.8%), P. issachenkonii AF316144 (95.0%), P. undina X82140 (96.7%), P. elyakovii AF082562 (98.3%), P. distincta AF082564 (98.1%), P. haloplanktis X67024 (97.1%), P. nigrifaciens X82146 (97.6%), and P. antartica X98336(94.3%). Therefore, the strain CHO-33 was determined to be Pseudoalteromonas agarovorans CHO-33, a taxon that is physiologically, chemotaxonomically, and phylogenetically distinct from the related strains.
Environmental factors effecting saccharification from alginate using Pseudoalteromonas agarovorans CHO-33 were investigated in flask cultures. The cell concentrations increased from 0.2 to 0.7 OD at 660 nm when the algitation rate increased from 0 to 180 rpm. On the other hand, the maximum concentration of sugar was obtained at 6.8 g/L after 3 days of culture at 15 rpm. After 2 days of preculture at 29℃, the sugar concentration peaked at 9.55 g/L after 3 days of culture. When 30 g/L of NaCl was used, the maximum concentration of sugar, 10.12 g/L, was obtained after 3 days of culture. Yeast extract and peptone were the best nitrogen source for effective saccharification. Especially, the sugar concentration was 10.8 g/L after 3 days of culture using a mixture of 1.0 g/L of yeast extract and 1.0 g/L of peptone.
Under optimum conditions of culture and media using Pseudoalteromonas agarovorans CHO-33, scale-up for effective saccharification from alginate was carried out in 5 L flasks. The cell concentration after 2 days of culture was 0.2 to 0.3 OD at 660 nm and showed no further increase after 3 day of culture. The sugar concentrations from alginate were increased with increasing culture time to 11.95 g/L after 2 days of culture. The rate of saccharification was 0.25 g sugar/hr, which was about 16.0 fold higher than that of S. maltophilia.
Alternative Author(s)
Yu Lan Piao
조선대학교 화학공학과
일반대학원 화학공학과
Awarded Date
박옥란. (2007). Isolation of pseudoalteromonas agarovorans and optimization of saccharification.
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General Graduate School > 3. Theses(Master)
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