Dataset Information

Pre-concentration of microalga Euglena gracilis by alkalescent pH treatment and flocculation mechanism of Ca₃(PO₄)₂, Mg₃(PO₄)₂, and derivatives.

ABSTRACT:

Background

Microalgae are widely be used in carbon sequestration, food supplements, natural pigments, polyunsaturated fatty acids, biofuel applications, and wastewater treatment. However, the difficulties incurred in algae cell separation and harvesting, and the exorbitant cost required to overcome these challenges, are the primary limitations to large-scale industrial application of microalgae technology.

Results

Herein, we explore the potential of inducing flocculation by adjusting the pH for pre-concentrating Euglena gracilis. Our results demonstrate that flocculation can be induced by increasing the medium pH to 8.5; however, most of the algae cells were broken by increasing the pH?>?10. Magnesium phosphate, calcium phosphate, and their derivatives precipitation jointly led to flocculation, although calcium phosphate and its derivatives precipitation had a greater effect.

Conclusions

This study demonstrates that pH treatment-induced flocculation is efficient and feasible for the pre-concentration of E. gracilis under a pilot-scale culture system. Moreover, it also maintained the microalgae cells' integrity, chlorophyll production, and increased paramylon production. These findings provide a theoretical basis for reducing the cost of large-scale E. gracilis harvesting; as well as provide a reference for harvesting other microalgae.

SUBMITTER: Wu M

PROVIDER: S-EPMC7260821 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Publications

Pre-concentration of microalga <i>Euglena gracilis</i> by alkalescent pH treatment and flocculation mechanism of Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, Mg<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, and derivatives.

Wu Mingcan M Li Jing J Qin Huan H Lei Anping A Zhu Hui H Hu Zhangli Z Wang Jiangxin J

Biotechnology for biofuels 20200529

<h4>Background</h4>Microalgae are widely be used in carbon sequestration, food supplements, natural pigments, polyunsaturated fatty acids, biofuel applications, and wastewater treatment. However, the difficulties incurred in algae cell separation and harvesting, and the exorbitant cost required to overcome these challenges, are the primary limitations to large-scale industrial application of microalgae technology.<h4>Results</h4>Herein, we explore the potential of inducing flocculation by adjust ...[more]

PMID: 32514310

Similar Datasets

Project description:BackgroundMicroalgae can contribute to more than 40% of global primary biomass production and are suitable candidates for various biotechnology applications such as food, feed products, drugs, fuels, and wastewater treatment. However, the primary limitation for large-scale algae production is the fact that algae requires large amounts of fresh water for cultivation. To address this issue, scientists around the world are working on ways to reuse the water to grow microalgae so that it can be grown in successive cycles without the need for fresh water.ResultsIn this study, we present the results when we cultivate microalgae with cultivation water that is purified and reused. Specifically, we purify the cultivation water using an ultrafiltration membrane (UFM) treatment and investigate how this treatment affects: the biomass and biochemical components of the microalgae; characteristics of microalgae growth inhibitors; the mechanism whereby potential growth inhibitors are secreted (followed using metabolomics analysis); the effect of activated carbon (AC) treatment and advanced oxidation processes (AOPs) on the removal of growth inhibitors of Euglena gracilis. Firstly, the results show that E. gracilis can be only cultivated through two growth cycles with water that has been filtered and reused, and the growth of E. gracilis is significantly inhibited when the water is used a third time. Secondly, as the number of reused water cycles increases, the Cl- concentration gradually increases in the cultivation water. When the Cl- concentration accumulates to a level of fivefold higher than that of the control, growth of E. gracilis is inhibited as the osmolality tolerance range is exceeded. Interestingly, the osmolality of the reused water can be reduced by replacing NH4Cl with urea as the source of nitrogen in the cultivation water. Thirdly, E. gracilis secretes humic acid (HA)-which is produced by the metabolic pathways for valine, leucine, and isoleucine biosynthesis and by linoleic acid metabolism-into the cultivation water. Because HA contains large fluorescent functional groups, specifically extended π(pi)-systems containing C=C and C=O groups and aromatic rings, we were able to observe a positive correlation between HA concentration and the rate of inhibition of E. gracilis growth using fluorescence spectroscopy. Moreover, photosynthetic efficiency is adversely interfered by HA, thereby reductions in the synthetic efficiency of paramylon and lipid in E. gracilis. In this way, we are able to confirm that HA is the main growth inhibitor of E. gracilis. Finally, we verify that all the HA is removed or converted into nutrients efficiently by AC or UV/H2O2/O3 treatments, respectively. As a result of these treatments, growth of E. gracilis is restored (AC treatment) and the amount of biomass is promoted (UV/H2O2/O3 treatment).ConclusionsThese studies have important practical and theoretical significance for the cyclic cultivation of E. gracilis and for saving water resources. Our work may also provide a useful reference for other microalgae cultivation.

Project description:Background:Euglena gracilis, a unicellular flagellated microalga, is regarded as one of the most promising species as microalgal feedstock for biofuels. Its lipids (mainly wax esters) are suitable for biodiesel and jet fuel. Culture of E. gracilis using wastewater effluent will improve the economics of E. gracilis biofuel production. Enhancement of the productivity of E. gracilis biomass is critical to creating a highly efficient biofuels production system. Certain bacteria have been found to promote microalgal growth by creating a favorable microenvironment. These bacteria have been characterized as microalgae growth-promoting bacteria (MGPB). Co-culture of microalgae with MGPB might offer an effective strategy to enhance microalgal biomass production in wastewater effluent culture systems. However, no MGPB has been identified to enhance the growth of E. gracilis. The objectives of this study were, therefore, to isolate and characterize the MGPB effective for E. gracilis and to demonstrate that the isolated MGPB indeed enhances the production of biomass and lipids by E. gracilis in wastewater effluent culture system. Results:A bacterium, Emticicia sp. EG3, which is capable of promoting the growth of microalga E. gracilis, was isolated from an E. gracilis-municipal wastewater effluent culture. Biomass production rate of E. gracilis was enhanced 3.5-fold and 3.1-fold by EG3 in the co-culture system using a medium of heat-sterilized and non-sterilized wastewater effluent, respectively, compared to growth in the same effluent culture but without EG3. Two-step culture system was examined as follows: E. gracilis was cultured with or without EG3 in wastewater effluent in the first step and was further grown in wastewater effluent in the second step. Production yields of biomass and lipids by E. gracilis were enhanced 3.2-fold and 2.9-fold, respectively, in the second step of the system in which E. gracilis was co-cultured with EG3 in the first step. Conclusion:Emticicia sp. EG3 is the first MGPB for E. gracilis. Growth-promoting bacteria such as EG3 will be promising agents for enhancing E. gracilis biomass/biofuel productivities.

Dataset Information

Pre-concentration of microalga Euglena gracilis by alkalescent pH treatment and flocculation mechanism of Ca₃(PO₄)₂, Mg₃(PO₄)₂, and derivatives.

Background

Results

Conclusions

Publications

Pre-concentration of microalga <i>Euglena gracilis</i> by alkalescent pH treatment and flocculation mechanism of Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, Mg<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, and derivatives.

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OmicsDI is part of the ELIXIR infrastructure

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Dataset Information

Pre-concentration of microalga Euglena gracilis by alkalescent pH treatment and flocculation mechanism of Ca3(PO4)2, Mg3(PO4)2, and derivatives.

Background

Results

Conclusions

Publications

Pre-concentration of microalga <i>Euglena gracilis</i> by alkalescent pH treatment and flocculation mechanism of Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, Mg<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, and derivatives.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Pre-concentration of microalga Euglena gracilis by alkalescent pH treatment and flocculation mechanism of Ca₃(PO₄)₂, Mg₃(PO₄)₂, and derivatives.