Progress toward a bicarbonate-based microalgae production system

For microalgae production systems, bicarbonate is a better carbon supply than bubbled CO2 gas in terms of carbon utilization efficiency, photobioreactor development, energy saving, and biomass harvesting. The carbon supply is the bottleneck in developing photobioreactors for low-cost microalgal biomass production, in contrast to the heterotrophic process, which is limited by oxygen supply. Recent progress suggests the potential of the bicarbonate-based integrated carbon capture and algae production system, to significantly reduce production costs and energy inputs in microalgae cultivation. Comprehensive utilization of natural power is a promising approach to further decrease energy consumption and improve the efficiency of the microalgae cultivation process in the future. Commercial applications of microalgae for biochemicals and fuels are hampered by their high production costs, and the use of conventional carbon supplies is a key reason. Bicarbonate has been proposed as an alternative carbon source due to its potential advantages in lower carbon supply costs, convenience for photobioreactor development, biomass harvesting, and labor and energy savings. We review recent progress in bicarbonate-based microalgae cultivation, which validated previous assumptions, suggested further advantages, and demonstrated potential to significantly reduce production cost. Future research should focus on improving production efficiency and reducing energy inputs, including optimizing photobioreactor design, comprehensive utilization of natural power, and automation in production systems. Commercial applications of microalgae for biochemicals and fuels are hampered by their high production costs, and the use of conventional carbon supplies is a key reason. Bicarbonate has been proposed as an alternative carbon source due to its potential advantages in lower carbon supply costs, convenience for photobioreactor development, biomass harvesting, and labor and energy savings. We review recent progress in bicarbonate-based microalgae cultivation, which validated previous assumptions, suggested further advantages, and demonstrated potential to significantly reduce production cost. Future research should focus on improving production efficiency and reducing energy inputs, including optimizing photobioreactor design, comprehensive utilization of natural power, and automation in production systems. the PBRs that were developed based on BICCAPS energy inputs. the ratio of bubbling volume to total cultivation volume. many microalgae acquired mechanisms that use energy to increase the CO2 concentrations in the proximity of Rubisco. the equipment used for CO2 bubbling, including the CO2 supply unit and the air blower. the saturating concentration of dissolved CO2 in equilibrium with the air. the dissolved CO2 concentration. use organic carbon as both a carbon source and an energy source for the growth of microbes. mass transfer coefficient of CO2, which is one of significant parameters to characterize and evaluate the mixing performance. mass transfer coefficient of O2, which is one of significant parameters to characterize and evaluate the mixing performance. mixing of algal culture liquid is required to keep cells in suspension, enhance mass transfer and gas exchange, and increase light utilization efficiency. The parameters of Reynolds number, flow velocity, mass transfer coefficient, and frequency of light/dark cycles, are commonly used to characterize and evaluate mixing performance. the energy produced in algal biomass divided by the total energy inputs. a culture pH at which the dissolved CO2 concentration is in equilibrium with the air, which is defined as: pH∗=pKa+logC032−+Ci0HC03−+2Ci0[2] [Ci0] represents the initial inorganic carbon concentration, [HCO3-] and [CO32-] is the concentration of the bicarbonate and carbonate when the dissolved CO2 concentration is in equilibrium with the air, respectively. the rate of CO2 consumption by microalgae photosynthesis.