Microalgae screening under CO stress: Growth and micro-nutrients removal efficiency.

Algae are one of the promising agents for greenhouse gas reduction and biofuel production. Different technologies have been developed and introduced in last decades for algae growth. Algae plays a very imperative role in the aquatic ecosystem regarding CO reduction and micro-nutrient removal. In present investigation, eight locally isolated (microalgae) strains and two pure strains were studied. The selected microalgae were grown under variable CO concentration and CO biofixation efficiencies along with micro-nutrient removal were monitored. Among selected strains, three strains (UMN266, UMN268 and UTEX 2714 showed adaptability up to 20% CO concentration with high biomass production of 1.3, 1.4 and 1.21g/L, respectively, whereas UTEX 78 and UMN 230 growth was slow under high CO concentration (20% CO). However, in step wise CO feeding, the growth of UTEX 78 and UMN 230 improved considerably and up to 0.9 and 0.97 (g/L) biomasses were recorded, respectively. All algae strains showed high growth rate at 2% CO feeding and nitrogen, phosphorus and ammonia removal from the simulated media were also significant. The fast-growing microalgae species tolerant up to 20% CO concentration and could be used for flue gas mitigation and valuable products production. These results can contribute to understand the nature of CO bio-fixation and microalgae could be a potential alternative for CO fixation.