Understanding the Effects of Carbon Dioxide and Bicarbonate on Chlamydomonas reinhardtii

Title:

Understanding the effects of carbon dioxide and bicarbonate on Chlamydomonas reinhardtii

Authors:

Humeyra B. Ulusoy-Erol¹, Jamie A. Hestekin¹, Christa N. Hestekin^1, YuPo J. Lin², Catherine Atchley¹, and Benjamin Drewry¹

¹ Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville,

AR, United States.

²Energy Systems, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, United States.

Abstract

Inorganic carbon has an important role on algae growth and lipid production systems. Even though most studies focus on carbon dioxide (CO₂) as an inorganic carbon (C_i) source, in seawater inorganic dissolved carbon is in the form of bicarbonate (HCO₃^-). Furthermore, during intense photosynthesis of microalgae, pH in the media tends to increase which leads to low CO₂ concentration. For commercial production of algae in applications including biofuel production, carbonate salts can provide an adequate source of C for high rate algae growth. Chlamydomonas reinhardtii, a single-celled, highly adaptable green alga, was used to understand the effects of C source for algae growth system. Bold’s Basal Medium (BBM), Tris-Acetate-Phosphate (TAP) medium, and BBM with the addition of sodium carbonate (BBMNa) on microalgae growth culture were analyzed. The results in different media indicated that the algae grown on BBMNa had higher biomass productivity (~20%) and produced more valuable fatty acids for the biodiesel industry than BBM and TAP mediums.