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Zhou Y, Cui X, Wu B, Wang Z, Liu Y, Ren T, Xia S, Rittmann BE. Microalgal extracellular polymeric substances (EPS) and their roles in cultivation, biomass harvesting, and bioproducts extraction. BIORESOURCE TECHNOLOGY 2024; 406:131054. [PMID: 38944317 DOI: 10.1016/j.biortech.2024.131054] [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: 05/14/2024] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/01/2024]
Abstract
Microalgae extracellular polymeric substances (EPS) are complex high-molecular-weight polymers and the physicochemical properties of EPS strongly affect the core features of microalgae cultivation and resource utilization. Revealing the key roles of EPS in microalgae life-cycle processes in an interesting and novelty topic to achieve energy-efficient practical application of microalgae. This review found that EPS showed positive effect in non-gas uptake, extracellular electron transfer, toxicity resistance and heterotrophic symbiosis, but negative impact in gas transfer and light utilization during microalgae cultivation. For biomass harvesting, EPS favored biomass flocculation and large-size cell self-flocculation, but unfavored small size microalgae self-flocculation, membrane filtration, charge neutralization and biomass dewatering. During bioproducts extraction, EPS exhibited positive impact in extractant uptake, but the opposite effect in cellular membrane permeability and cell rupture. Future research on microalgal EPS were also identified, which offer suggestions for comprehensive understanding of microalgal EPS roles in various scenarios.
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Affiliation(s)
- Yun Zhou
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Xiaocai Cui
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Beibei Wu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Ziqi Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Ying Liu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Tian Ren
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States of America
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Zhou JL, Yang ZY, Vadiveloo A, Li C, Chen QG, Chen DZ, Gao F. Enhancing lipid production and sedimentation of Chlorella pyrenoidosa in saline wastewater through the addition of agricultural phytohormones. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120445. [PMID: 38412732 DOI: 10.1016/j.jenvman.2024.120445] [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: 11/02/2023] [Revised: 01/13/2024] [Accepted: 02/20/2024] [Indexed: 02/29/2024]
Abstract
In this study, the effect of external agricultural phytohormones (mixed phytohormones) addition (1.0, 5.0, 10.0, and 20.0 mg L-1) on the growth performance, lipid productivity, and sedimentation efficiency of Chlorella pyrenoidosa cultivated in saline wastewater was investigated. Among the different concentrations evaluated, the highest biomass (1.00 g L-1) and lipid productivity (11.11 mg L-1 d-1) of microalgae were obtained at 10.0 mg L-1 agricultural phytohormones addition. Moreover, exogenous agricultural phytohormones also improved the sedimentation performance of C. pyrenoidosa, which was conducive to the harvest of microalgae resources, and the improvement of sedimentation performance was positively correlated with the amount of agricultural phytohormones used. The promotion of extracellular polymeric substances synthesis by phytohormones in microalgal cells could be considered as the reason for its promotion of microalgal sedimentation. Transcriptome analysis revealed that the addition of phytohormones upregulated the expression of genes related to the mitogen-activated protein kinase (MAPK)-mediated phytohormone signaling pathway and lipid synthesis, thereby improving salinity tolerance and lipid production in C. pyrenoidosa. Overall, agricultural phytohormones provide an effective and inexpensive strategy for increasing the lipid productivity and sedimentation efficiency of microalgae cultured in saline wastewater.
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Affiliation(s)
- Jin-Long Zhou
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Zi-Yan Yang
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Ashiwin Vadiveloo
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Perth, 6150, Australia
| | - Chen Li
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Qing-Guo Chen
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Dong-Zhi Chen
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Feng Gao
- Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, 316000, China.
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Shitanaka T, Fujioka H, Khan M, Kaur M, Du ZY, Khanal SK. Recent advances in microalgal production, harvesting, prediction, optimization, and control strategies. BIORESOURCE TECHNOLOGY 2024; 391:129924. [PMID: 37925082 DOI: 10.1016/j.biortech.2023.129924] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/06/2023]
Abstract
The market value of microalgae has grown exponentially over the past two decades, due to their use in the pharmaceutical, nutraceutical, cosmetic, and aquatic/animal feed industries. In particular, high-value products such as omega-3 fatty acids, proteins, and pigments derived from microalgae have high demand. However, the supply of these high-value microalgal bioproducts is hampered by several critical factors, including low biomass and bioproduct yields, inefficiencies in monitoring microalgal growth, and costly harvesting methods. To overcome these constraints, strategies such as synthetic biology, bubble generation, photobioreactor designs, electro-/magnetic-/bioflocculation, and artificial intelligence integration in microalgal production are being explored. These strategies have significant promise in improving the production of microalgae, which will further boost market availability of algal-derived bioproducts. This review focuses on the recent advances in these technologies. Furthermore, this review aims to provide a critical analysis of the challenges in existing algae bioprocessing methods, and highlights future research directions.
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Affiliation(s)
- Ty Shitanaka
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Haylee Fujioka
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Muzammil Khan
- Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Manpreet Kaur
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Zhi-Yan Du
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States.
| | - Samir Kumar Khanal
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States; Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States.
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Huang J, Cheng S, Zhang Y, Teng J, Zhang M, Lin H. Optimizing aeration intensity to enhance self-flocculation in algal-bacterial symbiosis systems. CHEMOSPHERE 2023; 341:140064. [PMID: 37673189 DOI: 10.1016/j.chemosphere.2023.140064] [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: 08/01/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/08/2023]
Abstract
Effectuating optimal wastewater treatment via algae-bacterial symbiosis (ABS) systems necessitates the precise selection of aeration intensity. This study pioneers an in-depth investigation into the interplay of aeration intensity on the microalgal-bacterial consortia's self-flocculation efficacy and the overall treatment performance within ABS systems. The research provides evidence for a direct association between aeration intensity and biomass proliferation, indicating enhanced pollutant removal efficiency with escalated intensities (1.0 and 1.5 L min-1), though the variance lacks statistical significance. The peak self-flocculation efficacy of the microalgal-bacterial consortium (82.39% at 30 min) was manifested at an aeration intensity of 1.0 L min-1. The meticulous analysis of biomass properties showed the complexity of self-flocculation capacity in the consortium, which involves a dynamic interplay of several pivotal factors, including floc size, zeta potential, and EPS content. In situations where these factors pose conflicting influences, the determining factor emerges as the dominant influencer. In this study, the optimal aeration intensity was identified as 1 L min-1, shedding light on the critical threshold for ABS system operation. This study not only enriches the understanding of microalgal-bacterial wastewater treatment mechanisms but also fosters innovative strategies to enhance the performance of such systems.
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Affiliation(s)
- Jiahui Huang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
| | - Sihan Cheng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
| | - Yuwei Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
| | - Jiaheng Teng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
| | - Meijia Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, China.
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Cui N, Feng Y, He X, Gu H, Zhao P. Extracellular polymeric substance profiling and biophysical analysis reveal influence factors of spontaneous flocculation in rich lipid alga Heveochlorella sp. Yu. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157655. [PMID: 35908705 DOI: 10.1016/j.scitotenv.2022.157655] [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: 06/14/2022] [Revised: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
Microalgae harvest and lipid accumulation were important factors influencing commercialized development of microalgae biodiesel. Spontaneous flocculation was an ideal method in microalgae harvest, but few rich lipid microalgae could be harvested by spontaneous flocculation. Rich lipid alga Heveochlorella sp. Yu has a characteristic of spontaneous flocculation to be harvested. Heveochlorella sp. Yu has high lipid productivity (105.24 mg L-1 d-1) and fine spontaneous flocculation efficiency (82.93 %, 2 h) on early stationary phase (day 9). The polysaccharides consisting of glucose, mannose, galactose, rhamnose and fructose (8.67:4.90:3.27:2.16:1) in loose-bound extracellular polymeric substance (LB-EPS) might make great contribution in microalgae flocculation. Meanwhile, the zeta potential close to zero was also beneficial to microalgae flocculation. Besides, the adhesion free energy related with cells adhesion was detected by thermomechanical analysis. Afterward, Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was utilized to quantitatively evaluate short-range interactions involved in the spontaneous aggregation among cells. Collectively, biophysical analyses indicated that content and composition of EPS, Zeta potential, thermodynamic parameter and total interaction based on XDLVO theory were closely connected with spontaneous flocculation in microalga Yu. Our study provided a harvest-simplified process of rich microalgae, which proposes a new idea for commercial development of microalgae biodiesel.
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Affiliation(s)
- Na Cui
- Faculty of Life Sciences and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Yongjie Feng
- Faculty of Life Sciences and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Ximeng He
- Faculty of Life Sciences and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Hong Gu
- Faculty of Life Sciences and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Peng Zhao
- Faculty of Life Sciences and Technology, Kunming University of Science and Technology, Kunming 650500, China.
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Cui N, Xiao J, Feng Y, Zhao Y, Yu X, Xu JW, Li T, Zhao P. Antioxidants enhance lipid productivity in Heveochlorella sp. Yu. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102235] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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