Ammonium Bicarbonate as Nutrient Substitute for Improving Biomass Productivity of Chlorella variabilis

Abstract

Sodium bicarbonate was replaced with ammonium bicarbonate, recovered from effluent of the pigment industry, for cultivation of CSMCRI's Chlorella variabilis (ATCC PTA 12198) with enhanced biomass and lipid productivity. Compared to Zarrouk's medium, utilizing ammonium bicarbonate in the medium instead of sodium bicarbonate yielded better biomass and lipid productivity in a shorter production time of 9 d in a 5‐L flask. The modified medium containing ammonium bicarbonate also yielded a higher total content of reducing sugar, which can be used for bioethanol production or as carbon source for further mixotrophic growth of C. variabilis.

Novel Bio-regeneration Concept via Using Rich Solution as Nutrition Resource for Microalgae Cultivation: Effect of pH and Feeding Modes

“…However, the salinity of the medium would gradually increase due to the accumulation of sodion if sodium carbonate was used as an absorption solvent . As an alternative solvent for the absorption–microalgae hybrid process, ammonia could absorb CO 2 and generate ammonia bicarbonate, which could simultaneously provide nitrogen and carbon for microalgae. , Meanwhile, the escaped nitrogen (in the form of NH 3 in high purity) from the bioconversion column could be recycled to the absorber for subsequent CO 2 capture. Nevertheless, it should be noted that ammonia toxicity might exist when ammonia is released at high speed and in high concentration, both of which would adversely affect the microalgae growth. , Especially, when the pH of the culture medium is higher than 9.0, the NH 3 escape rate will increase and lead to a high NH 3 concentration environment .…”

“…23 As an alternative solvent for the absorption−microalgae hybrid process, ammonia could absorb CO 2 and generate ammonia bicarbonate, which could simultaneously provide nitrogen and carbon for microalgae. 24,25 Meanwhile, the escaped nitrogen (in the form of NH 3 in high purity) from the bioconversion column could be recycled to the absorber for subsequent CO 2 capture. Nevertheless, it should be noted that ammonia toxicity might exist when ammonia is released at high speed and in high concentration, both of which would adversely affect the microalgae growth.…”