Study of the inhibitory effect of the media culture parameters and cell population to increase the biomass production of Dunaliella tertiolecta

Document Type: Original Research Papers


Department of biology, University of Isfahan, Isfahan, Iran


Microalgal growth curve, after the exponential phase, shows a stationary phase where algal
biomass production is inhibited and remains constant by some factors such as nutrient
depletion and intrinsic behavior. The present study is concerned with evaluating effects of
the culture medium condition and intrinsic behavior on biomass production by Dunaliella
tertiolecta. To this end, effect of pH, nutrient concentration, CO2 (NaHCO3) concentration,
possible secreted substances, and cell density on the biomass production by D. tertiolecta
were investigated. The results showed that biomass yield can be significantly affected by pH
(p<0.01) and nutrient (p<0.05). In a combination of pH and nutrient, the biomass was found to
be more influenced by the pH, compared with the nutrients. The results showed a significant
interaction between nutrient and NaHCO3 (p<0.05), suggesting that CO2 concentration may
limit biomass production only when sufficient nutrients are available. Nutrients concentration
and biomass production showed a direct correlation (p<0.05). The rate of reaching the
maximum biomass was showed to be increased in higher nutrients concentration; however,
the maximum point could not to be affected. The existence of secreted compounds with
inhibitory effect on the growth was not observed. The inhibitory effect of the cell density on
biomass production can not be confirmed.