The Growth and EPA Synthesis of Shewanella oneidensis MR-1 and Expectation of EPA Biosynthetic Pathway

  • Jeong, Young-Su (Department of Biological Engineering, Inha University) ;
  • Song, Sang-Kyu (Department of Biological Engineering, Inha University) ;
  • Lee, Su-Jin (Department of Biological Engineering, Inha University) ;
  • Hur, Byung-Ki (Department of Biological Engineering, Inha University)
  • 발행 : 2006.04.30

초록

Shewanella oneidensis MR-1 has the ability to inhale certain metals and chemical compounds and exhale these materials in an altered state; as a result, this microorganism has been widely applied in bioremediation protocols. However, the relevant characteristics of cell growth and biosynthesis of PuFAs have yet to be thoroughly investigated. Therefore, in this study, we have attempted to characterize the growth and fatty acid profiles of S. oneidensis MR-1 under a variety of temperature conditions. The fastest growth of S. oneidensis MR-1 was observed at $30^{\circ}C$, with a specific growth rate and doubling time of $0.6885h^{-1}\;and\;1.007 h$. The maximum cell mass of this microorganism was elicited at a temperature of $4^{\circ}C$. The eicosapentaenoic acid (EPA) synthesis of S. oneidensis MR-1 was evaluated under these different culture temperatures. S. oneidensis MR-1 was found not to synthesize EPA at temperatures in excess of $30^{\circ}C$, but was shown to synthesize EPA at temperatures below $30^{\circ}C$. The EPA content was found to increase with decreases in temperature. We then evaluated the EPA biosynthetic pathway, using a phylogenetic tree predicted on 16s rRNA sequences, and the homology of ORFs between S. oneidensis MR-1 and Shewanella putrefaciens SCRC-2738, which is known to harbor a polyketide synthase (PKS)-like module. The phylogenetic tree revealed that MR-1 was very closely related to both Moritella sp., which is known to synthesize DHA via a PKS-like pathway, and S. putrefaciens, which has been reported to synthesize EPA via an identical pathway. The homology between the PKS-like module of S. putrefaciens SCRC-2738 and the entire genome of S. oneidensis MR-1 was also analyzed, in order to mine the genes associated with the PKS-like pathway in S. oneidensis MR-1. A putative PKS-like module for EPA biosynthesis was verified by this analysis, and was also corroborated by the experimental finding that S. oneidensis MR-1 was able to synthesize EPA without the expression of $dihomo-{\gamma}-linoleic$ acid (DGLA) and arachidonic acid (AA) formed during EPA synthesis via the FAS pathway.

키워드

참고문헌

  1. Metz, J. G., P. Roessler, D. Facciotti, C. Levering, F. Dittrich, M. Lassner, R. Valentine, K. Lardizabal, F. Domergue, A. Yamada, K. Yazawa, V. Knauf, and J. Browse (2001) Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes. Science 293: 290-293 https://doi.org/10.1126/science.1059593
  2. Braden, L. M. and K. K. Carroll (1986) Dietary polyunsaturated fat in relation to mammary carcinogenesis in rats. Lipids 21: 285-288 https://doi.org/10.1007/BF02536414
  3. Singh, A. and O. P. Ward (1996) Production of high yields of docosahexaenoic acid by Thraustochytrium roseum ATCC 28210. J. Ind. Microbiol. 16: 370-373 https://doi.org/10.1007/BF01570118
  4. Ward, O. P. (1995) Microbial Production of Long-Chain PUFAs. Inform 6: 683-688
  5. Napier, J. A. (2002) Plumbing the depths of PUFA biosynthesis: a novel polyketide synthase-like pathway from marine organisms. Trends Plant Sci. 7: 51-54 https://doi.org/10.1016/S1360-1385(01)02191-4
  6. Kato, C. and Y. Nogi (2001) Correlation between phylogenetic structure and function: examples from deep-sea Shewanella. FEMS Microbiol. Ecol. 35: 223-230 https://doi.org/10.1111/j.1574-6941.2001.tb00807.x
  7. Nealson, K. H. and D. A. Saffarini (1994) Iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation. Annu. Rev. Microbiol. 48: 311-343 https://doi.org/10.1146/annurev.mi.48.100194.001523
  8. Abboud, R., R. Popa, V. Souza-Egipsy, C. S. Giometti, S. Tollaksen, J. J. Mosher, R. H. Findlay, and K. H. Nealson (2005) Low-temperature growth of Shewanella oneidensis MR-1. Appl. Environ. Microbiol. 71: 811-816 https://doi.org/10.1128/AEM.71.2.811-816.2005
  9. Lepage, G. and C. C. Roy (1984) Improved recovery of fatty acid through direct transesterification without prior extraction or purification. J. Lipid Res. 25: 1391-1396
  10. Myers, C. R. and K. H. Nealson (1988) Bacterial manganese reduction and growth with manganese oxide as the sole electron acceptor. Science 240: 1319-1321 https://doi.org/10.1126/science.240.4857.1319
  11. Mills, E. L. and K. T. Holeck (2001) Oneida lake: undergoing ecological change. Clearwaters 31: 22-25
  12. Hur, B.-K., D.-W. Cho, H.-J. Kim, C.-I. Park, and H.-J. Suh (2002) Effect of culture conditions on growth and production of docosahexaenoic acid (DHA) using Thraustochytrium aureum ATCC 34304. Biotechnol. Bioprocess Eng. 7: 10-15 https://doi.org/10.1007/BF02935873
  13. Panoff, J. M., D. Corroler, B. Thammavongs, and P. Boutibonnes (1997) Differentiation between cold shock proteins and cold acclimation proteins in a mesophilic gram-positive bacterium, Enterococcus faecalis JH2-2. J. Bacteriol. 179: 4451-4454 https://doi.org/10.1128/jb.179.13.4451-4454.1997
  14. Bajpai, P. K., P. Bajpai, and O. P. Ward (1991) Optimization of production of docosahexaenoic acid (DHA) by Thraustochytrium aureum ATCC 34304. J. Am. Oil Chem. Soc. 68: 509-514 https://doi.org/10.1007/BF02663823
  15. Yazawa, K. (1996) Production of eicosapentaenoic acid from marine bacteria. Lipids 31 Suppl: S297-S300 https://doi.org/10.1007/BF02637095
  16. Higashiyama, K., S. Fujikawa, E. Y. Park, and S. Shimizu (2002) Production of arachidonic acid by Mortierella fungi. Biotechnol. Bioprocess Eng. 7: 252-262 https://doi.org/10.1007/BF02932833
  17. Tey, B. T., K. H. Yong, H. P. Ong, T. C. Ling, S. T. Ong, Y. P. Tan, A. Ariff, and W. S. Tan (2004) Optimal conditions for hepatitis B core antigen production in shaked flask fermentation. Biotechnol. Bioprocess Eng. 9: 374-378 https://doi.org/10.1007/BF02933060