Potential enhancement of photosynthetic energy conversion in algal mass culture

Actual laboratory data obtained from steady‐state Dunaliella tertiolecta cultures grown under a wide range of photon flux densities were used in a simple model to calculate daily production in a conventional algal mass culture system. In spite of large physiological and biochemical variations between low‐light‐ (LL) and high light‐ (HL) adapted cultures, the overall calculated daily productivity is almost identical for both strains grown at optimal conditions. When production of fine biochemicals is considered, however, a hypothetical HL strain, which cannot shade adapt, is advantageous. Based on biochemical and biophysical analysis of D. tertiolecta responses to growth irradiance levels, specific targets are defined for genetic manipulation to enhance productivity in algal mass culture systems. The targets identified are (1) amplification of the carboxylation enzyme ribulose‐1,5‐bisphosphate carboxylase‐oxygenase relative to the electron transport complexes, which should increase photosynthetic capacity at light saturation, and (2) enlargement of the light‐harvesting complexes by varying their pigment composition in order to increase light harvesting at low photon flux densities.

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