Glutamate production from CO2 by Marine Cyanobacterium Synechococcus sp. - Using a Novel Biosolar Reactor Employing Light-Diffusing Optical Fibers

Tadashi Matsunaga*, Haruko Takeyama, Hiroaki Sudo, Nobuo Oyama, Shunsuke Ariura, Hiroyuki Takano, Morio Hirano, J. Grant Burgess, Koji Sode, Noriyuki Nakamura

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


A photobioreactor was constructed in the form of a Perspex column 900 mm tall with an internal diameter of 70 mm. The reactor volume was 1.8 L and the light source consisted of a metal-halide lamp to reproduce sunlight. Light was distributed through the culture using a new type of optical fiber that diffuses light out through its surface, perpendicular to the fiber axis. A cluster of 661 light-diffusing optical fibers (LDOFs) pass from the light source through the reactor column (60-cm culture depth) and are connected to a mirror at the top of the reactor. This biosolar reactor has been used for the production of glutamate from CO2 by the marine cyanobacterium Synechococcus sp. NKBG040607. We present here details of the construction of the biosolar reactor and characterization of its properties. The effect of light intensity on glutamate production was measured. Carbon dioxide-to-glutamate conversion ratios were determined at different cell densities: the maximum conversion ratio (28%) was achieved at a cell density of 3x108 cells/mL. A comparison of glutamate production using the LDOF biosolar reactor described here with production by batch culture using free or immobilized cells showed that use of an optical-fiber biosolar reactor increased glutamate-production efficiency 6.75-fold. We conclude that as a result of its high surface-to-volume ratio (692/m) increased photoproduction of useful compounds may be achieved. Such a system is generally applicable to all aspects of photobiotechnology.

Original languageEnglish
Pages (from-to)157-167
Number of pages11
JournalApplied Biochemistry and Biotechnology
Issue number1
Publication statusPublished - 1991 Mar 1
Externally publishedYes


  • Glutamate
  • Synechococcus
  • biosolar reactor
  • marine cyanobacteria
  • optical fiber

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology


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