Effect of oxygen on the growth (yield) ofChlorella vulgaris

✍ Scribed by Takahira Ogawa; Takao Fujii; Shuichi Aiba

• Publisher: Springer
• Year: 1980
• Tongue: English
• Weight: 552 KB
• Volume: 127
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00414351

✦ Synopsis

The growth yield of Chlorella vulgar&, YkJ defined as g cells harvested per kJ of light energy absorbed by the cells, was assessed in a turbidostat culture by varying COz and 02 partial pressures (Pco2 andpo2). The value of YkJ ranged from 3.1 • 10-3 to 5.0 x 10-3g cells/kJ under light-limited conditions [Pco2 = 1.0~2.4%, Po2 = 0~65%; total pressure of gas (composed of COz, 02 and N2) = 1 atm]. In the lightlimited environment, the algal specific growth rate # deteriorated appreciably with the increase ofpo 2. The deterioration accounts for the above range of YkJ observed. The growth inhibition due to oxygen that was defined by subtracting from 1.0 the ratio of # at given values ofpo ~ to that atpo2 = 0 % extended from 0.07-0.30 (7-30%). However, glycolate could not be detected in the turbidostat culture. Isotopic experiments on the specific rate of 14CO2 uptake also revealed that the inhibition due to oxygen was from 2 2 -38 % when Po2 was varied from 0 to nearly 100 %. These effects of oxygen were discussed, referring to the activity of ribulose-l,5-bisphosphate carboxylase that is inhibited competitively by oxygen.