Applied Biochemistry and Biotechnology

, Volume 78, Issue 1–3, pp 389–399 | Cite as

Accumulation of biopolymers in activated sludge biomass

  • Hong Chua
  • Peter H. F. Yu
  • Chee K. Ma


In this study, activated sludge bacteria from a conventional wastewater treatment process were induced to accumulate polyhydroxyalkanoates (PHAs) under different carbon-nitrogen (C:N) ratios. As the C:N ratio increased from 20 to 140, specific polymer yield increased to a maximum of 0.38 g of polymer/g of dry cell mass while specific growth yield decreased. The highest overall polymer production yield of 0.11 g of polymer/g of carbonaceous substrate consumed was achieved using a C:N ratio of 100. Moreover, the composition of polymer accumulated was dependent on the valeric acid content in the feed. Copolymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was produced in the presence of valeric acid. The 3-hydroxyvalerate (3HV) mole fraction in the copolymer was linearly related tovaleric content in the feed, which reached a maximum of 54% when valeric acid was used as sole carbon source. When the 3HV U in the polymer increased from 0–54 mol%, the melting temperature decreased from 178° to 99°C. Thus, the composition, and hence the mechanical properties, of the copolymer produced from activated sludge can be controlled by adjusting the mole fraction of valeric acid in the feed medium.

Index Entries

Activated sludge carbon-nitrogen ratio wastewater treatment butyric-valeric acid ratio poly(3-hydroxybutyrate-co-3-hydroxyvalerate) 


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  1. 1.
    Chua, H., Yu, P. H. F., Xing, S., and Ho, L. Y. (1995), J. Plast. Technol. 18, 132–148.Google Scholar
  2. 2.
    Hong Kong Government Industry Department (1991), in Techno-Economic and Market Research Study of Hong Kong Plastic Industry, vol. 1, 1990–1991, Hong Kong Government Press.Google Scholar
  3. 3.
    Chang, H. N. (1994), in Better Living Through Innovative Biochemical Engineering, Teo, W. K., ed., Singapore University Press, National University of Singapore, Singapore, pp. 24–30.Google Scholar
  4. 4.
    Chua, H., Yu, P. H. F., Xing, S., and Ho, L. Y. (1995), Potential of Biodegradable Plastics as Environmentally-Friendly Substitutes for Conventional Plastics in Hong Kong. Presented in 17th Symposium on Biotechnology for Fuelsand Chemicals, May 1995, CO.Google Scholar
  5. 5.
    Sang Yup Lee (1996), Biotechnol. Bioeng. 49, 1–14.CrossRefGoogle Scholar
  6. 6.
    Suzuki, T., Yamane, T., and Shimizu, S. (1986), Appl. Microbiol. Biotechnol. 24, 370–374.CrossRefGoogle Scholar
  7. 7.
    Maness, P.-C. and Weaver, P. F. (1994), Appl. Biochem. Biotech. 45/46, 395–407.Google Scholar
  8. 8.
    Page, W. J. (1989), Appl. Microbiol. Biotechnol. 31, 329–333.CrossRefGoogle Scholar
  9. 9.
    Page, W. J. (1992), FEMS Microbiol. Rev. 103, 149–158.CrossRefGoogle Scholar
  10. 10.
    Page, W. J. and Knosp, O. (1989), Appl. Environ. Microbiol. 55, 1334–1339.Google Scholar
  11. 11.
    Chua, H., Yu, P. H. F., and Ho, L. Y. (1997), Appl. Biochem. Biotechnol. 63, 627–635.Google Scholar
  12. 12.
    Chua, H., Yu, P. H. F., and Ho, L. Y. (1997), J. IES Chem. Eng. 37(2), 9–13.Google Scholar
  13. 13.
    Kim, G. J., Yun, K. Y., Bae, K. S., and Rhee, Y. H. (1992), Biotechnol. Lett. 14, 27–32.CrossRefGoogle Scholar
  14. 14.
    American Public Health Association (1995), Standard Methods for the Examination of Water and Wastewater, 19th ed., Washington, DC.Google Scholar
  15. 15.
    Lowell, L. W. and Edwin, N. D. (1972), Env. Sci. Technol. 6(2), 161–164.CrossRefGoogle Scholar
  16. 16.
    Ho, L. Y. (1997), Synthesis of Environmentally Friendly Materials, Master Thesis, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.Google Scholar
  17. 17.
    Doi, Y., Segawa, A., and Kunioka, M. (1990), Intl. J. Biol. Macronol. 12, 106–111.CrossRefGoogle Scholar
  18. 18.
    Bluhm, T. and Marchessualt, R. H. (1988), Can. Chem. News. 40, 25–26.Google Scholar
  19. 19.
    Ishihara, Y., Shimizu, H., and Shioya, S. (1996), J. Ferment. Bioeng. 81, 422–428.CrossRefGoogle Scholar
  20. 20.
    Yamane, T. (1993), Biotechnol. Bioeng. 41, 165–170.CrossRefGoogle Scholar
  21. 21.
    Dave, H., Ramakrishna, C., and Desai, J. D. (1996), Indian J. Exp. Biol. 34, 216–219.Google Scholar

Copyright information

© Humana Press Inc. 1999

Authors and Affiliations

  • Hong Chua
    • 1
  • Peter H. F. Yu
    • 2
  • Chee K. Ma
    • 1
  1. 1.Department of Civil and Structural EngineeringThe Hong Kong Polytechnic UniversityHung HomHong Kong, China
  2. 2.Department of Applied Biology and Chemical TechnologyThe Hong Kong Polytechnic UniversityHung HomHong Kong, China

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