Investigation of Pb(II) bioremediation potential of algae and cyanobacteria strains isolated from polluted water

Lakmali, W.G.Madusha; Athukorala, A. D. S.; Jayasundera, Keerthi B.

doi:10.1016/j.wse.2022.04.003

Cited by 12 publications

(1 citation statement)

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“…Eukaryotic microalgae biomass produced from these treatments is usually exploited as feedstock for biofuel production since the biomass can contain up to 40%-70% lipids (Kothari et al, 2013;Chokshi et al, 2016;Khalaji et al, 2023;Paulenco et al, 2023). On the other hand, cyanobacteria, which constitute a group of ancient ubiquitous phototrophic bacteria (Abed et al, 2009;Garcia-Pichel, 2009), are resistant to extreme conditions of temperature, pH, heavy metals, and high salinity and, thus, are suitable for bioremediation (Gaurav et al, 2018;Ahmad, 2022;Lakmali et al, 2022). Although cyanobacteria have the ability to successfully remove nitrogen and phosphate from wastewaters (Lincoln et al, 1996;Kumar et al, 2011;El-Sheekh et al, 2011;Jitha and Madhu, 2016;Kabariya and Ramani, 2016;Ouhsassi et al, 2020;Álvarez et al, 2020;Ahmad, 2022), they have been mainly investigated for the production of high-value compounds, both naturally produced and metabolically engineered, thanks to their ease of genetic manipulation.…”

Section: Introductionmentioning

confidence: 99%

Coupling dairy wastewaters for nutritional balancing and water recycling: sustainable heterologous 2-phenylethanol production by engineered cyanobacteria

Usai,

Cordara,

Mazzocchi

et al. 2024

Front. Bioeng. Biotechnol.

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Microalgae biotechnology is hampered by the high production costs and the massive usage of water during large-volume cultivations. These drawbacks can be softened by the production of high-value compounds and by adopting metabolic engineering strategies to improve their performances and productivity. Today, the most sustainable approach is the exploitation of industrial wastewaters for microalgae cultivation, which couples valuable biomass production with water resource recovery. Among the food processing sectors, the dairy industry generates the largest volume of wastewaters through the manufacturing process. These effluents are typically rich in dissolved organic matter and nutrients, which make it a challenging and expensive waste stream for companies to manage. Nevertheless, these rich wastewaters represent an appealing resource for microalgal biotechnology. In this study, we propose a sustainable approach for high-value compound production from dairy wastewaters through cyanobacteria. This strategy is based on a metabolically engineered strain of the model cyanobacterium Synechococcus elongatus PCC 7942 (already published elsewhere) for 2-phenylethanol (2-PE). 2-PE is a high-value aromatic compound that is widely employed as a fragrance in the food and cosmetics industry thanks to its pleasant floral scent. First, we qualitatively assessed the impact of four dairy effluents on cyanobacterial growth to identify the most promising substrates. Both tank-washing water and the liquid effluent of exhausted sludge resulted as suitable nutrient sources. Thus, we created an ideal buffer system by combining the two wastewaters while simultaneously providing balanced nutrition and completely avoiding the need for fresh water. The combination of 75% liquid effluent of exhausted sludge and 25% tank-washing water with a fine-tuning ammonium supplementation yielded 180 mg L−1 of 2-PE and a biomass concentration of 0.6 gDW L-1 within 10 days. The mixture of 90% exhausted sludge and 10% washing water produced the highest yield of 2-PE (205 mg L−1) and biomass accumulation (0.7 gDW L−1), although in 16 days. Through these treatments, the phosphates were completely consumed, and nitrogen was removed in a range of 74%–77%. Overall, our approach significantly valorized water recycling and the exploitation of valuable wastewaters to circularly produce marketable compounds via microalgae biotechnology, laying a promising groundwork for subsequent implementation and scale-up.

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