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Zou X, Zhao S, Xu K, Fang C, Shen Z, Yan C, Dong L, Qin Z, Zhao X, Zhao J, Liang X. Eco-friendly microalgae harvesting using lipid-cored particles with a comparative life-cycle assessment. BIORESOURCE TECHNOLOGY 2024; 392:130023. [PMID: 37972903 DOI: 10.1016/j.biortech.2023.130023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 11/19/2023]
Abstract
This study proposed an innovative approach using lipid-cored particles (LCPs) aimed at addressing the efficiency, cost, and environmental impact challenges in microalgae harvesting. Cetyltrimethylammonium bromide (CTAB) and chitosan (CS) were used to modify LCPs and to optimize efficiency and investigate the mechanisms of harvesting with Chlorella vulgaris. Results showed that a maximum harvesting efficiency of 97.14 % was achieved using CS-LCPs. Zeta potential and microscopic images revealed the presence of embedded CS-LCPs within microalgal flocs. Fractal dimension data suggested looser aggregates of CS-LCPs and Chlorella vulgaris, corroborated by Excitation-emission matrices (EEM) analysis further confirmation the presence of bridging networks. Moreover, life cycle assessment of five harvesting methods pointed freshwater ecotoxicity potential (FEP) and terrestrial ecotoxicity potential (TEP) as major environmental impacts, mainly from flocculant use, carrier production, and electricity consumption. Notably, LCPs showed the lowest global warming potential (GWP) at 1.54 kg CO2 eq, offering a viable, low-carbon, cost-effective harvesting alternative.
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Affiliation(s)
- Xiaotong Zou
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China; School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, Xi'an, 710048, China.
| | - Shaohua Zhao
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Kaiwei Xu
- College of Computer Science and Technology, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Changqing Fang
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China; School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, Xi'an, 710048, China.
| | - Zhou Shen
- School of Life and Environmental Sciences, Shaoxing University, Huancheng West Road 508, Shaoxing 312000, China
| | - Chang Yan
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Liming Dong
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Zhaoyue Qin
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Xinyue Zhao
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Jiajia Zhao
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
| | - Xiongbo Liang
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an, 710048, China
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Xu K, Zou W, Peng B, Guo C, Zou X. Lipid Droplets from Plants and Microalgae: Characteristics, Extractions, and Applications. BIOLOGY 2023; 12:biology12040594. [PMID: 37106794 PMCID: PMC10135979 DOI: 10.3390/biology12040594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023]
Abstract
Plant and algal LDs are gaining popularity as a promising non-chemical technology for the production of lipids and oils. In general, these organelles are composed of a neutral lipid core surrounded by a phospholipid monolayer and various surface-associated proteins. Many studies have shown that LDs are involved in numerous biological processes such as lipid trafficking and signaling, membrane remodeling, and intercellular organelle communications. To fully exploit the potential of LDs for scientific research and commercial applications, it is important to develop suitable extraction processes that preserve their properties and functions. However, research on LD extraction strategies is limited. This review first describes recent progress in understanding the characteristics of LDs, and then systematically introduces LD extraction strategies. Finally, the potential functions and applications of LDs in various fields are discussed. Overall, this review provides valuable insights into the properties and functions of LDs, as well as potential approaches for their extraction and utilization. It is hoped that these findings will inspire further research and innovation in the field of LD-based technology.
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Affiliation(s)
- Kaiwei Xu
- Institute of Systems Security and Control, College of Computer Science and Technology, Xi'an University of Science and Technology, Xi'an 710054, China
- Shaanxi Provincial Key Laboratory of Land Consolidation, Chang'an University, Xi'an 710074, China
| | - Wen Zou
- State Owned SIDA Machinery Manufacturing, Xianyang 712201, China
| | - Biao Peng
- Shaanxi Provincial Key Laboratory of Land Consolidation, Chang'an University, Xi'an 710074, China
- Key Laboratory of Degraded and Unused Land Consolidation Engineering, Ministry of Natural Resources, Xi'an 710021, China
| | - Chao Guo
- Key Laboratory of Degraded and Unused Land Consolidation Engineering, Ministry of Natural Resources, Xi'an 710021, China
| | - Xiaotong Zou
- Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi'an University of Technology, Xi'an 710048, China
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Xu K, Zou X, Chang W, Qu Y, Li Y. Microalgae harvesting technique using ballasted flotation: A review. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119439] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Wen H, Zhang H, He M, Zhang X. A novel approach for harvesting of the microalgae Chlorella vulgaris with Moringa oleifera extracts microspheres by Buoy-bead flotation method. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zou X, Xu K, Chang W, Qu Y, Li Y. Rapid extraction of lipid from wet microalgae biomass by a novel buoyant beads and ultrasound assisted solvent extraction method. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102431] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Efficient Bioflocculation of Chlorella vulgaris with a Chitosan and Walnut Protein Extract. BIOLOGY 2021; 10:biology10050352. [PMID: 33919407 PMCID: PMC8143315 DOI: 10.3390/biology10050352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 11/29/2022]
Abstract
Simple Summary With the increase in population size, global climate changes, and the improvement of living standards, the fossil fuel resources may run out in the future. Microalgae have been considered the next generation of sustainable and renewable feedstock to produce biofuel and a large spectrum of high-value products, such as healthy oils, carotenoids, and proteins. Unlike terrestrial plants, the production of added-value chemicals from microalgal species is not seasonal; they can be grown under climate-independent conditions in bioreactors; can use wastewater as a source of nutrients, contributing to wastewater treatment; and can convert CO2 into organic compounds more efficiently. However, the utilization of microalgal biomass is heavily dependent on microalgal biomass harvesting and concentration technology. Flocculation represents a relatively low-cost and efficient approach for the harvesting of microalgal biomass at a large scale. However, in traditional flocculation, most of the chemical flocculants covalently bind to the microalgal surfaces, contaminating the final product, which significantly limits their application. This study aims to develop an efficient and convenient bioflocculation technique to harvest microalgae. Abstract Bioflocculation represents an attractive technology for harvesting microalgae with the potential additive effect of flocculants on the production of added-value chemicals. Chitosan, as a cationic polyelectrolyte, is widely used as a non-toxic, biodegradable bioflocculant for many algal species. The high cost of chitosan makes its large-scale application economically challenging, which triggered research on reducing its amount using co-flocculation with other components. In our study, chitosan alone at a concentration 10 mg/L showed up to an 89% flocculation efficiency for Chlorella vulgaris. Walnut protein extract (WPE) alone showed a modest level (up to 40%) of flocculation efficiency. The presence of WPE increased chitosan’s flocculation efficiency up to 98% at a reduced concentration of chitosan (6 mg/L). Assessment of co-flocculation efficiency at a broad region of pH showed the maximum harvesting efficiency at a neutral pH. Fourier transform infrared spectroscopy, floc size analysis, and microscopy suggested that the dual flocculation with chitosan and walnut protein is a result of the chemical interaction between the components that form a web-like structure, enhancing the bridging and sweeping ability of chitosan. Co-flocculation of chitosan with walnut protein extract, a low-value leftover from walnut oil production, represents an efficient and relatively cheap system for microalgal harvesting.
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Laamanen C, Desjardins S, Senhorinho G, Scott J. Harvesting microalgae for health beneficial dietary supplements. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102189] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Tan JS, Lee SY, Chew KW, Lam MK, Lim JW, Ho SH, Show PL. A review on microalgae cultivation and harvesting, and their biomass extraction processing using ionic liquids. Bioengineered 2020; 11:116-129. [PMID: 31909681 PMCID: PMC6999644 DOI: 10.1080/21655979.2020.1711626] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The richness of high-value bio-compounds derived from microalgae has made microalgae a promising and sustainable source of useful product. The present work starts with a review on the usage of open pond and photobioreactor in culturing various microalgae strains, followed by an in-depth evaluation on the common harvesting techniques used to collect microalgae from culture medium. The harvesting methods discussed include filtration, centrifugation, flocculation, and flotation. Additionally, the advanced extraction technologies using ionic liquids as extractive solvents applied to extract high-value bio-compounds such as lipids, carbohydrates, proteins, and other bioactive compounds from microalgae biomass are summarized and discussed. However, more work needs to be done to fully utilize the potential of microalgae biomass for the application in large-scale production of biofuels, food additives, and nutritive supplements.
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Affiliation(s)
- Jia Sen Tan
- Department of Biotechnology, Faculty of Applied Science, UCSI University, Kuala Lumpur, Malaysia
| | - Sze Ying Lee
- Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Sungai Long Campus, Kajang, Malaysia
| | - Kit Wayne Chew
- School of Mathematical Sciences, Faculty of Science and Engineering, University of Nottingham Malaysia, Selangor, Malaysia
| | - Man Kee Lam
- Chemical Engineering Department, Universiti Teknologi PETRONAS, Perak, Malaysia.,Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
| | - Jun Wei Lim
- Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia.,Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Pau Loke Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Malaysia
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Zou X, Xu K, Xue Y, Qu Y, Li Y. Removal of harmful algal blooms in freshwater by buoyant-bead flotation using chitosan-coated fly ash cenospheres. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:29239-29247. [PMID: 32440871 DOI: 10.1007/s11356-020-09293-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Harmful algal blooms (HABs) are a growing problem worldwide, damaging human and ecosystem health. In this study, a novel buoyant-bead flotation (BBF) method using chitosan-coated fly ash cenospheres (CFACs) was developed to remove HABs in freshwater. To achieve a high removal efficiency of harmful algae (Chlorella vulgaris, Scenedesmus quadricauda, and Microcystis aeruginosa), this study investigated the effects of chitosan/fly ash ratios in CFAC composite, CFAC concentration, flotation time, and pH values on the microalgae removal. The optimized ratio of CFACs is 0.1:12, and the optimized CFAC concentration is 0.3-0.7 g L-1. However, the lower or higher ratios (0.1:4, 0.1:8, 0.1:16) result in microalgae reaching a zero-point charge too late or early, which failed to effectively remove HABs with an appropriate coal fly ash dosage. An optimized removal efficiency of 98.50% for Microcystis aeruginosa was reached at pH of 6.0. The optimized efficiency of Scenedesmus quadricauda and Chlorella vulgaris was 99.37% and 91.63%, respectively, at pH of 8.0. At neutral pH conditions, the surface charge of microalgae cells and CFACs are different, promoting aggregate formation. When CFACs were used to remove microalgae, aggregate size significantly influenced removal efficiency. Meanwhile, at the optimized pH and concentration, the removal efficiency of all three algal species exceeded 90.00% in 5 min. The study highlights an efficient and inexpensive method for removing HABs and obtains the optimized operational conditions.
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Affiliation(s)
- Xiaotong Zou
- School of Water and Environment, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Kaiwei Xu
- School of Water and Environment, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yating Xue
- School of Water and Environment, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yanhui Qu
- School of Water and Environment, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yanpeng Li
- School of Water and Environment, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China.
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Xi'an, 710054, People's Republic of China.
- Shaanxi Key Laboratory of Land Consolidation, Xi'an, 710075, People's Republic of China.
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Yin Z, Zhu L, Li S, Hu T, Chu R, Mo F, Hu D, Liu C, Li B. A comprehensive review on cultivation and harvesting of microalgae for biodiesel production: Environmental pollution control and future directions. BIORESOURCE TECHNOLOGY 2020; 301:122804. [PMID: 31982297 DOI: 10.1016/j.biortech.2020.122804] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/07/2020] [Accepted: 01/10/2020] [Indexed: 05/05/2023]
Abstract
Biodiesel is one of the best promising candidates in response to the energy crisis, since it has the capability to minimize most of the environmental problems. Microalgae, as the feedstock of third-generation biodiesel, are considered as one of the most sustainable resources. However, microalgae production for biodiesel feedstock on a large scale is still limited, because of the influences of lipid contents, biomass productivities, lipid extraction technologies, the water used in microalgae cultivation and processes of biomass harvesting. This paper firstly reviews the recent advances in microalgae cultivation and growth processes. Subsequently, current microalgae harvesting technologies are summarized and flocculation mechanisms are analyzed, while the characteristics that the ideal harvesting methods should have are summarized. This review also summarizes the environmental pollution control performances and the key challenges in future. The key suggestions and conclusions in the paper can offer a promising roadmap for the cost-effective biodiesel production.
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Affiliation(s)
- Zhihong Yin
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Liandong Zhu
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China; Faculty of Technology, and Vaasa Energy Institute, University of Vaasa, PO Box 700, FI-65101 Vaasa, Finland.
| | - Shuangxi Li
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Tianyi Hu
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Ruoyu Chu
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Fan Mo
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Dan Hu
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Chenchen Liu
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
| | - Bin Li
- School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology, and Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China
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Zou X, Xu K, Xue Y, Qu Y, Li Y. Interactions of Chlorella vulgaris and fly ash cenospheres in heat-aided ballasted flotation. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Xu K, Zou X, Wen H, Xue Y, Qu Y, Li Y. Effects of multi-temperature regimes on cultivation of microalgae in municipal wastewater to simultaneously remove nutrients and produce biomass. Appl Microbiol Biotechnol 2019; 103:8255-8265. [PMID: 31396677 DOI: 10.1007/s00253-019-10051-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/18/2019] [Accepted: 07/26/2019] [Indexed: 01/19/2023]
Abstract
Coupling algal cultivation with wastewater treatment due to their potentials to alleviate energy crisis and reduce environmental burden has attracted the increased attention in recent years. However, these microalgal-based processes are challenging since daily and seasonal temperature fluctuation may affect microalgal growth in wastewater, and the effects of the temperature regimes on microalgal biomass production and wastewater nutrient removal remain unclear. In this study, Chlorella vulgaris was continuously cultured for 15 days in municipal wastewater to investigate the effects on the algal biomass and wastewater nutrient removal in three temperature regimes: (1) low temperature (4 °C), (2) high temperature (35 °C), and (3) alternating high-low temperature (35 °C in the day: 4 °C at night). Compared with the other two temperature regimes, the high-low temperature conditions generated the most biomass (1.62 g L-1), the highest biomass production rate (99.21 mg L-1 day-1), and most efficient removal of COD, TN, NH3-N, and TP (83.0%, 96.5%, 97.8%, and 99.2%, respectively). In addition, the polysaccharides, proteins, lipid content, and fatty acid methyl ester composition analysis indicates that in alternating high-low temperature condition, biomass production increased the potential for biofuel production, and there was the highest lipid content (26.4% of total dry biomass). The results showed that the nutrients except COD were all efficiently removed in these temperature conditions, and the alternating high-low temperature condition showed great potential to generate algal biomass and alleviate the wastewater nutrients. This study provides some valuable information for large-scale algal cultivation in wastewater and microalgal-based wastewater treatments.
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Affiliation(s)
- Kaiwei Xu
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Xiaotong Zou
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Hao Wen
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yating Xue
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yanhui Qu
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China
| | - Yanpeng Li
- School of Environmental Science and Engineering, Chang'an University, Yanta Road #126, Yanta District, Xi'an, 710054, People's Republic of China.
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Xi'an, 710054, People's Republic of China.
- Shaanxi Key Laboratory of Land Consolidation, Xi'an, 710075, People's Republic of China.
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Zou X, Xu K, Wen H, Xue Y, Qu Y, Li Y. Efficient microalgae harvesting using a thermal flotation method with response surface methodology. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2019; 80:426-436. [PMID: 31596254 DOI: 10.2166/wst.2019.287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Thermal pre-flocculation to enable dispersed air flotation is an economical and ecofriendly technology for harvesting microalgae from water. However, the underlying mechanism and optimal conditions for this method remain unclear. In this study, Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus) were harvested using a thermal flotation process. The surface structure and characteristics (morphology, electricity, and hydrophobicity) of the microalgae were analyzed using FT-IR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), zeta potential, and a hydrophobic test. Further, response surface methodology (RSM) was used to optimize the flotation process. The hydrophobicity of S. obliquus exceeded that of C. vulgaris; as such, under the thermal pre-flocculation, S. obliquus (88.16%) was harvested more efficiently than C. vulgaris (47.16%). Thermal pre-flocculation denatured the lipids, carbohydrate, and proteins of microalgal cell surfaces. This resulted in a decrease in the electrostatic repulsion between the cells and air bubbles. The highest harvesting efficiency was 91.96% at 70 °C, 1,412 rpm, and 13.36 min. The results of this study demonstrate the potential for economic and ecofriendly harvesting of microalgae for biofuels and other bioproducts industries.
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Affiliation(s)
- Xiaotong Zou
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail:
| | - Kaiwei Xu
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail:
| | - Hao Wen
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail:
| | - Yating Xue
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail:
| | - Yanhui Qu
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail:
| | - Yanpeng Li
- School of Environmental Science and Engineering, Chang'an University, Xi'an 710054, China E-mail: ; Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Xi'an 710054, China and Shaanxi Key Laboratory of Land Consolidation, Xi'an 710075, China
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Abstract
In today’s world of environmental strain, wastewater treatment has become a, more or less, conventional application of flotation—as for instance, in the oil, food, or chemical industries, and in potable water treatment. In this paper, different flotation methods (such as ion, adsorbing colloid, and adsorptive flotation, including biosorption) and techniques will be reviewed; and, in order to explain them further, several applications of these from the laboratory (General and Inorganic Chemical Technology) at Aristotle University of Thessaloniki, Greece (AUTh) will be presented and analyzed, with the main focus on sustainability. The application of flotation as a separation process, when applied in pollution control or during water treatment, was often criticized due to the possible toxicity of the applied collectors; however, the use of biosurfactants may alleviate this concern and enhance its further acceptability.
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Furuhashi Y, Honda R, Noguchi M, Hara-Yamamura H, Kobayashi S, Higashimine K, Hasegawa H. Optimum conditions of pH, temperature and preculture for biosorption of europium by microalgae Acutodesmus acuminatus. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2018.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wen H, Zou X, Xu K, Shen Z, Ren X, Li Y. Buoy-bead flotation application for the harvesting of microalgae and mechanistic analysis of significant factors. Bioprocess Biosyst Eng 2018; 42:391-400. [DOI: 10.1007/s00449-018-2043-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 11/10/2018] [Indexed: 10/27/2022]
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