Optimization of CO2 Supply for the Intensive Cultivation of Chlorella sorokiniana IPPAS C-1 in the Laboratory and Pilot-Scale Flat-Panel Photobioreactors

Abstract

Microalgae are increasingly being used for capturing carbon dioxide and converting it into valuable metabolites and biologically active compounds on an industrial scale. The efficient production of microalgae biomass requires the optimization of resources, including CO2. Here, we estimated the productivity of Chlorella sorokiniana IPPAS C-1 depending on CO2 concentrations and the ventilation coefficient of the gas-air mixture (GAM) in flat-panel photobioreactors (FP-PBRs) at laboratory (5 L) and pilot (18 L) scales. For the laboratory scale, the PBRs operated at 900 µmol quanta m−2 s−1 and 35.5 ± 0.5 °C; the optimal CO2 flow rate was estimated at 3 mL CO2 per 1 L of suspension per minute, which corresponds to 1.5% CO2 in the GAM and an aeration rate of 0.2 vvm. These parameters, being scaled up within the pilot PBRs, resulted in a high specific growth rate (µ ≈ 0.1 h−1) and high specific productivity (Psp ≈ 1 g dw L−1 d−1). The principles of increasing the efficiency of the intensive cultivation of C. sorokiniana IPPAS C-1 are discussed. These principles are relevant for the development of technological regimes for the industrial production of Chlorella in flat-panel PBRs of various sizes.

Biomass and lipid production by the native green microalgae Chlorella sorokiniana in response to nutrients, light intensity, and carbon dioxide: experimental and modeling approach

“…The carbon dioxide concentration was studied for scaling up C. sorokiniana cultures in flat panel PBRs, yielding an optimal concentration at a laboratory scale (5 L) of 1.5% with a flow rate of 0.2 vvm. At a pilot scale (18 L), Gabrielyan et al (2022) found that when keeping the volumetric flow rate of CO 2 constant, the increase in the rate of aeration noticeably enhanced the growth and biomass yield. They also found that the direct transfer of specific cultivation parameters from a small to a large scale does not ensure a proportional increase in biomass yield ( Gabrielyan et al, 2022 ).…”

“…At a pilot scale (18 L), Gabrielyan et al (2022) found that when keeping the volumetric flow rate of CO 2 constant, the increase in the rate of aeration noticeably enhanced the growth and biomass yield. They also found that the direct transfer of specific cultivation parameters from a small to a large scale does not ensure a proportional increase in biomass yield ( Gabrielyan et al, 2022 ). To enhance the technology used to capture carbon through microalgae, improvements are required that implement environmentally friendly methods for growing microalgae, such as using flue gas and wastewater treatment technologies.…”

Plants, Cells, Algae, and Cyanobacteria In Vitro and Cryobank Collections at the Institute of Plant Physiology, Russian Academy of Sciences—A Platform for Research and Production Center

“…The analysis demonstrated that ROS accumulation and redox state changes are universal triggers for stress responses in cyanobacteria [184][185][186]. Unicellular coccoid green microalgae with robust growth characteristics; thermotolerant [187]; used in studies on endogenous regulation of photosynthesis and metabolism [188][189][190][191][192][193][194][195]; under stressed conditions, it accumulates mainly starch [191,192]; acts as a reference strain for biotechnological applications [175,188,189,[196][197][198].…”

“…Some strains with robust growth characteristics, such as Chlorella sorokiniana IPPAS C-1 and C. vulgaris Beijerinck IPPAS C-2 have been used as reference strains for different biotechnological applications [ 175 , 196 , 197 , 198 , 199 , 200 ] ( Table 5 ), including the design and testing of the novel models of photobioreactors [ 175 , 198 ] ( Figure 14 d,e). Synechocystis sp.…”

Carbon Footprint Reduction and Climate Change Mitigation: A Review of the Approaches, Technologies, and Implementation Challenges

“…The efficiency of microalgae at assimilating CO 2 using solar energy is 10-50 times higher than that of terrestrial plants [186,187]. In terms of CO 2 , 1.0 kg of algae biomass may assimilate ~1.83 kg of CO 2 , which makes it possible to rear microalgae near thermal power plants or any other sources of greenhouse gases [181,182,188]. Currently, microalgae are actively used to obtain a wide range of biologically active components, such as proteins (including the production of amino acids), fats (including polyunsaturated fatty acids), carbohydrates (including starch and fiber), carotenoids, pigments, vitamins, and biologically active forms of major and trace elements [189][190][191].…”