Biomass Production Potential of a Wastewater Alga Chlorella vulgaris ARC 1 under Elevated Levels of CO2 and Temperature

• Main Authors: Senthil Chinnasamy, Ashish Bhatnagar, Balasubramanian Ramakrishnan, Keshav C. Das
• Format: Article
• Language: English
• Published: MDPI AG 2009-02-01
• Series: International Journal of Molecular Sciences
• Subjects: Biomass; carbonic anhydrase; Chlorella; CO2; 14C uptake; microalgae; temperature
• Online Access: http://www.mdpi.com/1422-0067/10/2/518/

The growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (ranging from 0.036 to 20%) and temperature (30, 40 and 50oC). The highest chlorophyll concentration (11 µg mL-1) and biomass (210 µg mL-1), which were 60 and 20 times more than that of C. vulgaris at ambient CO2 (0.036%), were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them. Results showed that the optimum temperature for biomass production was 30oC under elevated CO2 (6%). Although increases in temperature above 30oC resulted in concomitant decrease in growth response, their adverse effects were significantly subdued at elevated CO2. There were also differential responses of the alga, assessed in terms of NaH14CO3 uptake and carbonic anhydrase activity, to increases in temperature at elevated CO2. The results indicated that Chlorella vulgaris grew better at elevated CO2 level at 30oC, albeit with lesser efficiencies at higher temperatures.