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Exploring an in situ LED-illuminated isothermal micro-calorimetric method to investigating the thermodynamic behavior of Chlorella vulgaris during CO2 bio-fixation

Russel, Mohammad, Liu, Changrui, Alam, Asraful, Wang, Fei, Yao, Jun, Daroch, Maurycy, Shah, Mahfuzur Rahman, Wang, Zhongming
Environmental science and pollution research international 2018 v.25 no.19 pp. 18519-18527
Chlorella vulgaris, biomass, calorimetry, carbon, carbon dioxide, carbon dioxide fixation, carbon sequestration, culture media, heat production, microalgae
Much endeavor has been dispensed recently to evaluate the potential of CO₂ mitigation by microalgae. We introduce an alternative, novel, LED-illumination isothermal microcalorimetric method to assess the thermodynamic behaviors of microalgae for better understanding of their carbon sequestration capacity. Microalgae thermodynamic behaviors were recorded as power-time curves, and their indices such as total heat evolution (QT), maximum power output (Pₘₐₓ) and heat generated by per algae cell (JN/Q) were obtained. The values for highest (74.80 g L⁻¹) and control sample (0.00 g L⁻¹) of QT, Pₘₐₓ and JN/Q were 20.85 and 2.32 J; 252.17 and 57.67 μW; 7.91 × ⁻⁰⁶ and 8.80 × ⁻⁰⁷ J cell⁻¹, respectively. According to the values of QT, a general order to promote the CO₂ sequestration was found at 74.8 g L⁻¹ > 29.92 g L⁻¹ > 14.96 g L⁻¹ > 7.48 g L⁻¹ > 0 g L⁻¹ of C sources, which directly corresponded to carbon availability in the growth medium. Chlorella vulgaris GIEC-179 showed the highest peak Pₘₐₓ at 74.8 g L⁻¹ concentration which was directly transformed to their biomass during bio-fixation of CO₂ process. This study is applicable for better understanding of CO₂ fixation performance of algae.