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Suhaimi N, Kumakubo R, Yoshino T, Maeda Y, Murata S, Tanaka T. Expansion of omega-3 polyunsaturated fatty acid metabolism of the oleaginous diatom Fistulifera solaris by genetic engineering. J Biosci Bioeng 2024; 138:105-110. [PMID: 38825559 DOI: 10.1016/j.jbiosc.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/30/2024] [Accepted: 05/14/2024] [Indexed: 06/04/2024]
Abstract
Omega-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) are widely used as additives in fish feed in the aquaculture sector. To date, the supply of omega-3 PUFAs have heavily depended upon fish oil production. As the need for omega-3 PUFAs supply for the growing population increases, a more sustainable approach is required to keep up with the demand. The oleaginous diatom Fistulifera solaris is known to synthesize EPA with the highest level among autotrophically cultured microalgae, however, this species does not accumulate significant amounts of DHA, which, in some cases, is required in aquaculture rather than EPA. This is likely due to the lack of expression of essential enzymes namely Δ5 elongase (Δ5ELO) and Δ4 desaturase. In this study, we identified endogenous Δ5ELO genes in F. solaris and introduced recombinant expression cassettes harboring Δ5ELO into F. solaris through bacterial conjugation. As a result, it managed to induce the synthesis of docosapentaenoic acid (DPA; C22:5n-3), a direct precursor of DHA. This study paves the way for expanding our understanding of the omega-3 PUFAs pathway using endogenous genes in the oleaginous diatom.
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Affiliation(s)
- Noraiza Suhaimi
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan
| | - Ryota Kumakubo
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan
| | - Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan; Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan
| | - Satoshi Murata
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan.
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2
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Kumari A, Pabbi S, Tyagi A. Recent advances in enhancing the production of long chain omega-3 fatty acids in microalgae. Crit Rev Food Sci Nutr 2023; 64:10564-10582. [PMID: 37357914 DOI: 10.1080/10408398.2023.2226720] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Omega-3 fatty acids have gained attention due to numerous health benefits. Eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) are long chain omega-3 fatty acids produced from precursor ALA (α-linolenic acid) in humans but their rate of biosynthesis is low, therefore, these must be present in diet or should be taken as supplements. The commercial sources of omega-3 fatty acids are limited to vegetable oils and marine sources. The rising concern about vegan source, fish aquaculture conservation and heavy metal contamination in fish has led to the search for their alternative source. Microalgae have gained importance due to the production of high-value EPA and DHA and can thus serve as a sustainable and promising source of long chain omega-3 fatty acids. Although the bottleneck lies in the optimization for enhanced production that involves strategies viz. strain selection, optimization of cultivation conditions, media, metabolic and genetic engineering approaches; while co-cultivation, use of nanoparticles and strategic blending have emerged as innovative approaches that have made microalgae as potential candidates for EPA and DHA production. This review highlights the possible strategies for the enhancement of EPA and DHA production in microalgae. This will pave the way for their large-scale production for human health benefits.
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Affiliation(s)
- Arti Kumari
- Division of Biochemistry, ICAR - Indian Agricultural Research Institute, New Delhi, India
| | - Sunil Pabbi
- Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India
| | - Aruna Tyagi
- Division of Biochemistry, ICAR - Indian Agricultural Research Institute, New Delhi, India
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3
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Sun KM, Wang J, Ju Q, Zhao Y, Kong X, Yuan C, Tian Y. The mitigating effects of diatom-bacteria biofilm on coastal harmful algal blooms: A lab-based study concerning species-specific competition and biofilm formation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117544. [PMID: 36842356 DOI: 10.1016/j.jenvman.2023.117544] [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: 11/19/2021] [Revised: 12/15/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Harmful algal blooms (HABs) in coastal areas severely affected the health of ecosystem and human beings. The HABs control by biological methods, especially for biofilms, has been research hotspots in freshwater ecosystem. However, the biofilm-relating control of HABs in marine environment was very limited. In the present study, we found the population growth of two harmful algal species, Prorocentrum obtusidens Schiller (formerly P. donghaiense Lu) and Heterosigma akashiwo, were inhibited by a diatom-bacteria biofilm. The highest inhibitory rate was 79.6 ± 2.1% for P. obtusidens when co-cultured with biofilm suspension, and was 88.6 ± 5.8% for H. akashiwo when co-cultured with the biofilm filtrate without nutrient replenishment. When nitrate and phosphate were added, the inhibition rate for P. obtusidens was 72.3 ± 2.0%, but the population inhibition was not found in H. akashiwo. It suggested that P. obtusidens was mainly inhibited via interference competition, while the inhibition of H. akashiwo was resulted from exploitation competition. We further investigated the role of fatty acids for the interference competition in P. obtusidens, and found that fatty acids at their environmental-relevance concentrations can inhibit the photosynthetic capacity of P. obtusidens, but cannot inhibit the population growth. The community of biofilm shifted, and was finally dominated by the photoheterotrophic bacterium Dinoroseobacter shibae, and the diatom Fistulifera sp. with relative abundance of higher than 90%. Our study indicated that the diatom-bacteria biofilm was likely the candidate for the HABs control in marine environment. D. shibae and Fistulifera sp. were probably the effective species in the biofilm.
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Affiliation(s)
- Kai-Ming Sun
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China; SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, Shandong, China
| | - Jingru Wang
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China
| | - Qing Ju
- Shandong Provincial Qingdao Eco-environment Monitoring Center, Qingdao, 266061, Shandong, China
| | - Yan Zhao
- College of Marine Life, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Xiangfeng Kong
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China
| | - Chao Yuan
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, Shandong, China.
| | - Yulu Tian
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
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Zhang B, Peng C, Zhang S, Zhang M, Li D, Wang X, Mao B. Comprehensive analysis of the combined flocculation and filtration process for microalgae harvesting at various operating parameters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159658. [PMID: 36302440 DOI: 10.1016/j.scitotenv.2022.159658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/13/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
The combined process of flocculation and filtration can improve algae harvesting performance by combining the benefits of both and overcoming the drawbacks. The entire process was thoroughly examined in this study, considering technical and economic feasibility under a variety of operating situations. Dead-end filtration was performed to evaluate the harvesting performance, the removal of extracellular organic matter and the changes of flocs. Cross-flow filtration was then carried out to explore the effect of operating parameters on permeate flux and assess the technical and economic feasibility. The optimum operating condition was to use 5 mg/L cationic polyacrylamide with 25 μm pore size and 0.1 m/s cross-flow velocity, under which a high harvesting efficiency of 95.2 %, a high average permeate flux of 55.5 m3/(m2 h) and a volumetric reduction factor of 118.9 were achieved. Algal floc analysis revealed that flocs formed by ferric chloride and polyaluminium sulfate tended to partially deconstruct into smaller pieces during the filtration process. In contrast, flocs formed by cationic polyacrylamide tended to aggregate into bigger flocs, which, when paired with the effect of flocculant dosage and membrane pore size, could explain the difference in filtration performance and membrane permeance. No negative effect on downstream technology was observed for the combined process. A significantly lowered estimated total cost of 0.139 $/kg under optimum operating condition was obtained compared to filtration without flocculation assisted (0.206 $/kg).
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Affiliation(s)
- Bingcong Zhang
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Cheng Peng
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Shuangshuang Zhang
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Miao Zhang
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Dan Li
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Xin Wang
- Department of Water Resource and Environmental Engineering, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China
| | - Bifei Mao
- Department of Chemistry, Biology and Materials, East China University of Technology, Guanglan Blvd 418, Nanchang, Jiangxi 330013, China.
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Maeda Y, Tanaka T. Molecular Insights into Lipoxygenases in Diatoms Based on Structure Prediction: a Pioneering Study on Lipoxygenases Found in Pseudo-nitzschia arenysensis and Fragilariopsis cylindrus. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:468-479. [PMID: 35397048 DOI: 10.1007/s10126-022-10120-4] [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: 12/27/2021] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Diatoms produce a variety of oxylipins which are oxygenated polyunsaturated fatty acids and are involved in chemical defense and intercellular communication, among other roles. Although the chemistry of diatom oxylipins has long been studied, the enzymes involved in their production, in particular lipoxygenase (LOX), which catalyzes the initial reaction of the synthesis, have not been discovered in diatom genomes. Recently, diatom LOXs were found in two species, Pseudo-nitzschia arenysensis (PaLOX) and Fragilariopsis cylindrus (FcLOX); however, the enzymology of these LOXs is largely unknown. In this review article, we discuss the potential functions of the diatom LOXs based on previously reported structures of LOXs derived from various organisms other than diatoms. Since the structures of PaLOX and FcLOX have not yet been solved, we discussed their functions, such as regio- and stereospecificities, on the basis of their structures predicted using a computational tool based on deep learning technology. Both diatom LOXs were predicted to conserve common core domains with relatively wide substrate-binding pockets. The stereo-determinant residues in PaLOX and FcLOX suggest S specificity. We assume that the highly conserved common core domain can be a clue to reveal unidentified lox genes from the accumulated diatom genome information with the aid of high-throughput structure prediction tools and structure-based alignment tools in the near future.
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Affiliation(s)
- Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
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6
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Shah AM, Yang W, Mohamed H, Zhang Y, Song Y. Microbes: A Hidden Treasure of Polyunsaturated Fatty Acids. Front Nutr 2022; 9:827837. [PMID: 35369055 PMCID: PMC8968027 DOI: 10.3389/fnut.2022.827837] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
Microbes have gained a lot of attention for their potential in producing polyunsaturated fatty acids (PUFAs). PUFAs are gaining scientific interest due to their important health-promoting effects on higher organisms including humans. The current sources of PUFAs (animal and plant) have associated limitations that have led to increased interest in microbial PUFAs as most reliable alternative source. The focus is on increasing the product value of existing oleaginous microbes or discovering new microbes by implementing new biotechnological strategies in order to compete with other sources. The multidisciplinary approaches, including metabolic engineering, high-throughput screening, tapping new microbial sources, genome-mining as well as co-culturing and elicitation for the production of PUFAs, have been considered and discussed in this review. The usage of agro-industrial wastes as alternative low-cost substrates in fermentation for high-value single-cell oil production has also been discussed. Multidisciplinary approaches combined with new technologies may help to uncover new microbial PUFA sources that may have nutraceutical and biotechnological importance.
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Affiliation(s)
- Aabid Manzoor Shah
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
| | - Wu Yang
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
| | - Hassan Mohamed
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Assiut, Egypt
| | - Yingtong Zhang
- Institute of Agricultural Facilities and Equipment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yuanda Song
- Colin Ratledge Center of Microbial Lipids, School of Agriculture Engineering and Food Sciences, Shandong University of Technology, Zibo, China
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7
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Yao J, Zhao M, Song L, Chen X, Zhang Z, Gao N. Characteristics of extracellular organic matters and the formation potential of disinfection by-products during the growth phases of M. aeruginosa and Synedra sp. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:14509-14521. [PMID: 34617221 DOI: 10.1007/s11356-021-16647-8] [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: 04/07/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Extracellular organic matter (EOM) is an important precursor of disinfection by-products (DBPs). Nowadays, little is known about changes in molecular weight (MW) and hydrophilic (HPI)/hydrophobic (HPO) fractions of EOM during the entire algal growth phase. In this study, a combined approach of fractionation procedure and parallel factor (PARAFAC) analysis was applied to characterize the EOM during the entire growth phase of two algal species (M. aeruginosa and Synedra sp.), and investigated the relationships between fluorescent component and the DBP formation potential (FP) in MW and HPI/HPO fractions. Thereinto, three components (including one protein-like component (C1), one humic-like component (C2), and one fulvic acid-like component (C3)) were identified by the PARAFAC model. For two algae, the HPI and high MW (> 100 kDa) fractions were both the main components of algal EOM in the three growth phases in terms of the dissolved organic carbon. The high MW fraction had more C1 compared with other MW fractions, especially for M. aeruginosa. Besides, the formation risk of EOM-derived DBPs from M. aeruginosa was lower than that from Synedra sp. The result of this study showed the FP of DBPs varied with fluorescent components of algal EOM fractions and also indicated that the humic-like substances were tended to form trichloromethane and the tryptophan-like substances were associated with dichloroacetic acid by canonical correspondence analysis for both two algae.
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Affiliation(s)
- Juanjuan Yao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 40045, China.
| | - Meng Zhao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 40045, China
| | - Lili Song
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 40045, China
| | - Xiangyu Chen
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 40045, China
| | - Zhi Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 40045, China
| | - Naiyun Gao
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China
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8
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Effects of fatty acid synthase-inhibitors on polyunsaturated fatty acid production in marine diatom Fistulifera solaris JPCC DA0580. J Biosci Bioeng 2022; 133:340-346. [DOI: 10.1016/j.jbiosc.2021.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/17/2021] [Accepted: 12/27/2021] [Indexed: 11/20/2022]
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Tanaka T, Maeda Y, Suhaimi N, Tsuneoka C, Nonoyama T, Yoshino T, Kato N, Lauersen KJ. Intron-mediated enhancement of transgene expression in the oleaginous diatom Fistulifera solaris towards bisabolene production. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Maeda Y, Tsuru Y, Matsumoto N, Nonoyama T, Yoshino T, Matsumoto M, Tanaka T. Prostaglandin production by the microalga with heterologous expression of cyclooxygenase. Biotechnol Bioeng 2021; 118:2734-2743. [PMID: 33851720 DOI: 10.1002/bit.27792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/30/2021] [Accepted: 04/05/2021] [Indexed: 01/28/2023]
Abstract
Prostaglandins (PGs) are the physiologically active compounds synthesized from C20 polyunsaturated fatty acids (PUFAs) by cyclooxygenase (COX) and a series of PG synthases, and are utilized as pharmaceuticals. Currently, commercialized PGs are mainly produced by chemical synthesis under harsh conditions. By contrast, bioproduction of PGs can be an alternative, environmental-friendly, and inexpensive process with genetic engineering of model plants, although these conventional host organisms contain a limited quantity of PG precursors. In this study, we established an efficient PG production process using the genetically engineered microalga Fistulifera solaris which is rich in C20 PUFAs. A cox gene derived from the red alga Agarophyton vermiculophyllum was introduced into F. solaris. As a result, a transformant clone with high cox expression produced PGs (i.e., PGD2 , PGE2 , PGF2α , and 15-ketoPGF2α derived from arachidonic acid, and PGD3 , PGE3 , and PGF3α derived from eicosapentaenoic acid) as revealed by liquid chromatography/mass spectrometry. The total content of PGs was 1290.4 ng/g of dry cell weight, which was higher than that produced in the transgenic plant reported previously. The results obtained in this study indicate that the C20 PUFA-rich microalga functionally expressing COX is a promising host for PG bioproduction.
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Affiliation(s)
- Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Yuki Tsuru
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Nana Matsumoto
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Tomomi Nonoyama
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Mitsufumi Matsumoto
- Biotechnology Laboratory, Electric Power Development Co., Ltd., Kitakyusyu, Fukuoka, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
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11
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Kashiyama Y, Ishizuka Y, Terauchi I, Matsuda T, Maeda Y, Yoshino T, Matsumoto M, Yabuki A, Bowler C, Tanaka T. Engineered chlorophyll catabolism conferring predator resistance for microalgal biomass production. Metab Eng 2021; 66:79-86. [PMID: 33862197 DOI: 10.1016/j.ymben.2021.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/27/2020] [Accepted: 03/27/2021] [Indexed: 01/27/2023]
Abstract
Production of valuable compounds including biofuels and pharmaceutical precursors derived from microalgae has garnered significant interest. Stable production of algal biomass is essential to make the microalgal industry commercially feasible. However, one of the largest issues is severe biological contamination by predators grazing the algal biomass, resulting in the crash of outdoor cultures. In the present study, we propose a novel engineering strategy for microalgae to cope with predators. The overexpression of plant chlorophyllase (CLH) in a microalga resulted in the enhancement of resistance to the predator. This result supported our hypothesis that CLH promotes chlorophyll breakdown in the chloroplasts of the microalgae when they are digested by the predator, generating the phototoxic catabolite chlorophyllide that damages the predator. To the best of our knowledge, this is the first study to establish predator-resistant microalgae by enhancing the CLH activity.
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Affiliation(s)
- Yuichiro Kashiyama
- Department of Applied Science and Engineering, Graduate School of Engineering, Fukui University of Technology, 3-6-1, Gakuen, Fukui, Fukui, 910-8505, Japan
| | - Yuki Ishizuka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Issei Terauchi
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Toshiki Matsuda
- Department of Applied Science and Engineering, Graduate School of Engineering, Fukui University of Technology, 3-6-1, Gakuen, Fukui, Fukui, 910-8505, Japan
| | - Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Mitsufumi Matsumoto
- Biotechnology Laboratory, Electric Power Development Co., Ltd, 1, Yanagisaki-machi, Wakamatsu-ku, Kitakyusyu, Fukuoka, 808-0111, Japan
| | - Akinori Yabuki
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Chris Bowler
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
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12
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Abstract
Eicosapentaenoic acid (EPA) is an omega-3 fatty acid which is an essential nutrient for both humans and animals. This review examines the global need for EPA, both in human nutrition and aquaculture. The potential shortfall in supply of this important nutrient as well as sustainability issues with wild-caught fish have generated increased interest into alternative sources of EPA. Various approaches are summarized, including heterotrophic production and the use of genetically modified microorganisms and plants. Studies on photoautotrophic production of EPA are extensively reviewed. Widely used species for large-scale production of EPA includes Phaeodactylum tricornutum and Nannochloropsis due to their robustness and relatively high growth rates and EPA content (typically 5% of dry biomass). Approaches for large-scale production have also been reviewed. Closed reactors like flat panels, tubular reactors and bubble columns may be the most suitable due to their high productivity. However, there is no agreement in the literature as to which design generates the lowest cost of production. The economics of the process has also been examined. The best estimates for large-scale (100 hectare) plants give EPA prices of the order 39-90 USD per kilogram. This is approximately ten times higher than the price of EPA derived from fish oil. Potential avenues for lowering the cost are highlighted, along with the need to better understand the advantages and disadvantages of different EPA production methods from a more holistic perspective.
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Affiliation(s)
- Wenjia Gu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
| | - John M Kavanagh
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
| | - Dale D McClure
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
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13
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Sethi D, Butler TO, Shuhaili F, Vaidyanathan S. Diatoms for Carbon Sequestration and Bio-Based Manufacturing. BIOLOGY 2020; 9:E217. [PMID: 32785088 PMCID: PMC7464044 DOI: 10.3390/biology9080217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
Carbon dioxide (CO2) is a major greenhouse gas responsible for climate change. Diatoms, a natural sink of atmospheric CO2, can be cultivated industrially in autotrophic and mixotrophic modes for the purpose of CO2 sequestration. In addition, the metabolic diversity exhibited by this group of photosynthetic organisms provides avenues to redirect the captured carbon into products of value. These include lipids, omega-3 fatty acids, pigments, antioxidants, exopolysaccharides, sulphated polysaccharides, and other valuable metabolites that can be produced in environmentally sustainable bio-manufacturing processes. To realize the potential of diatoms, expansion of our knowledge of carbon supply, CO2 uptake and fixation by these organisms, in conjunction with ways to enhance metabolic routing of the fixed carbon to products of value is required. In this review, current knowledge is explored, with an evaluation of the potential of diatoms for carbon capture and bio-based manufacturing.
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Affiliation(s)
- Deepak Sethi
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
| | - Thomas O. Butler
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
| | - Faqih Shuhaili
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
- School of Bioprocess Engineering, Universiti Malaysia Perlis (UniMAP), Arau 02600, Perlis, Malaysia
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
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14
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Marella TK, Tiwari A. Marine diatom Thalassiosira weissflogii based biorefinery for co-production of eicosapentaenoic acid and fucoxanthin. BIORESOURCE TECHNOLOGY 2020; 307:123245. [PMID: 32234591 DOI: 10.1016/j.biortech.2020.123245] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 06/11/2023]
Abstract
Diatom algae can produce bioactive compounds like fucoxanthin (FX) and ecosapentaenoic acid (EPA) which are of high demand in pharmaceutical and nutraceutical industries. Here, the influence of different light regimes in combination with major nutrients on growth, FX and EPA production by marine diatom Thalassiosira weissflogii were investigated. Batch cultures of T. weissflogii were illuminated under blue (BL), red (RL) and white (WL) light at two intensities. BL regime resulted in higher cell density with a specific growth rate of 2.49µ. Lipid productivity and lipid % as dry cell weight (DCW) was considerably higher in BL with EPA productivity of 33.4 mg L-1d-1. Fucoxanthin content as % DCW reached 0.95 (BL), 0.75 (RL) and 0.81 (WL) at mid exponential growth phase. The results further prove the plasticity of diatoms and provide a way for future metabolic engineering of T. weissflogii for potential microalgal bio-refinery for combined EPA and FX production.
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Affiliation(s)
- Thomas Kiran Marella
- International Crop Research Institute for Semi-arid Tropics (ICRISAT), Patancheru 502 324, Telangana State, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, 201 313, India.
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15
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Marella TK, López-Pacheco IY, Parra-Saldívar R, Dixit S, Tiwari A. Wealth from waste: Diatoms as tools for phycoremediation of wastewater and for obtaining value from the biomass. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 724:137960. [PMID: 32408422 DOI: 10.1016/j.scitotenv.2020.137960] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/13/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
Diatoms are a type of microalgae with diverse capabilities which make them useful for multiple applications. The abundance of diatoms in water bodies facilitates the removal of pollutants from wastewater originating from different industries, such as agriculture and other anthropogenic sources. The unique photosynthetic, cellular and metabolic characteristics of diatoms allows them to utilize pollutants like nitrate, iron, phosphate, molybdenum, silica, and heavy metals, such as copper, cadmium, chromium, lead, etc., which make diatoms a good option for wastewater treatment. In addition, the biomass produced by diatoms growth on wastewaters has diverse applications and can, therefore, be valuable. This review focusses on the unique capabilities of diatoms for wastewater remediation and the capture of carbon dioxide, concomitant with the generation of valuable products. Diatom biorefinery can be a sustainable solution to wastewater management, and the biomass obtained from treatment can be turned into biofuels, biofertilizers, nutritional supplements for animal production, and used for pharmaceutical applications containing bioactive compounds like EPA, DHA and pigments such as fucoxanthin.
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Affiliation(s)
- Thomas Kiran Marella
- International Crop Research Institute for Semi-arid Tropics (ICRISAT), Patancheru 502 324, Telangana State, India
| | - Itzel Y López-Pacheco
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Monterrey, Ave. Eugenio Garza Sada 2501, CP 64849 Monterrey, N.L., Mexico
| | - Roberto Parra-Saldívar
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Monterrey, Ave. Eugenio Garza Sada 2501, CP 64849 Monterrey, N.L., Mexico
| | - Sreenath Dixit
- International Crop Research Institute for Semi-arid Tropics (ICRISAT), Patancheru 502 324, Telangana State, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, 201 313, India.
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16
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Patel A, Karageorgou D, Rova E, Katapodis P, Rova U, Christakopoulos P, Matsakas L. An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries. Microorganisms 2020; 8:E434. [PMID: 32204542 PMCID: PMC7143722 DOI: 10.3390/microorganisms8030434] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 12/17/2022] Open
Abstract
Microorganisms are known to be natural oil producers in their cellular compartments. Microorganisms that accumulate more than 20% w/w of lipids on a cell dry weight basis are considered as oleaginous microorganisms. These are capable of synthesizing vast majority of fatty acids from short hydrocarbonated chain (C6) to long hydrocarbonated chain (C36), which may be saturated (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA), depending on the presence and number of double bonds in hydrocarbonated chains. Depending on the fatty acid profile, the oils obtained from oleaginous microorganisms are utilized as feedstock for either biodiesel production or as nutraceuticals. Mainly microalgae, bacteria, and yeasts are involved in the production of biodiesel, whereas thraustochytrids, fungi, and some of the microalgae are well known to be producers of very long-chain PUFA (omega-3 fatty acids). In this review article, the type of oleaginous microorganisms and their expertise in the field of biodiesel or omega-3 fatty acids, advances in metabolic engineering tools for enhanced lipid accumulation, upstream and downstream processing of lipids, including purification of biodiesel and concentration of omega-3 fatty acids are reviewed.
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Affiliation(s)
- Alok Patel
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden; (A.P.); (E.R.); (U.R.); (P.C.)
| | - Dimitra Karageorgou
- Laboratory of Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, Ioannina 45110, Greece; (D.K.); (P.K.)
| | - Emma Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden; (A.P.); (E.R.); (U.R.); (P.C.)
| | - Petros Katapodis
- Laboratory of Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, Ioannina 45110, Greece; (D.K.); (P.K.)
| | - Ulrika Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden; (A.P.); (E.R.); (U.R.); (P.C.)
| | - Paul Christakopoulos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden; (A.P.); (E.R.); (U.R.); (P.C.)
| | - Leonidas Matsakas
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden; (A.P.); (E.R.); (U.R.); (P.C.)
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17
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Abstract
Microalgae are unicellular organisms that act as the crucial primary producers all over the world, typically found in marine and freshwater environments. Most of them can live photo-autotrophically, reproduce rapidly, and accumulate biomass in a short period efficiently. To adapt to the uninterrupted change of the environment, they evolve and differentiate continuously. As a result, some of them evolve special abilities such as toleration of extreme environment, generation of sophisticated structure to adapt to the environment, and avoid predators. Microalgae are believed to be promising bioreactors because of their high lipid and pigment contents. Genetic engineering technologies have given revolutions in the microalgal industry, which decoded the secrets of microalgal genes, express recombinant genes in microalgal genomes, and largely soar the accumulation of interested components in transgenic microalgae. However, owing to several obstructions, the industry of transgenic microalgae is still immature. Here, we provide an overview to emphasize the advantage and imperfection of the existing transgenic microalgal bioreactors.
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Affiliation(s)
- Zhi-Cong Liang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Ming-Hua Liang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Jian-Guo Jiang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
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18
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Maeda Y, Nojima D, Sakurai M, Nomaguchi T, Ichikawa M, Ishizuka Y, Tanaka T. Genome analysis and genetic transformation of a water surface-floating microalga Chlorococcum sp. FFG039. Sci Rep 2019; 9:11200. [PMID: 31371830 PMCID: PMC6671960 DOI: 10.1038/s41598-019-47612-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/18/2019] [Indexed: 11/30/2022] Open
Abstract
Microalgal harvesting and dewatering are the main bottlenecks that need to be overcome to tap the potential of microalgae for production of valuable compounds. Water surface-floating microalgae form robust biofilms, float on the water surface along with gas bubbles entrapped under the biofilms, and have great potential to overcome these bottlenecks. However, little is known about the molecular mechanisms involved in the water surface-floating phenotype. In the present study, we analysed the genome sequence of a water surface-floating microalga Chlorococcum sp. FFG039, with a next generation sequencing technique to elucidate the underlying mechanisms. Comparative genomics study with Chlorococcum sp. FFG039 and other non-floating green microalgae revealed some of the unique gene families belonging to this floating microalga, which may be involved in biofilm formation. Furthermore, genetic transformation of this microalga was achieved with an electroporation method. The genome information and transformation techniques presented in this study will be useful to obtain molecular insights into the water surface-floating phenotype of Chlorococcum sp. FFG039.
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Affiliation(s)
- Yoshiaki Maeda
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Daisuke Nojima
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Miki Sakurai
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Tatsuhiro Nomaguchi
- Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan
| | - Momoko Ichikawa
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Yuki Ishizuka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.
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19
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Metabolic Innovations Underpinning the Origin and Diversification of the Diatom Chloroplast. Biomolecules 2019; 9:biom9080322. [PMID: 31366180 PMCID: PMC6723447 DOI: 10.3390/biom9080322] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
Of all the eukaryotic algal groups, diatoms make the most substantial contributions to photosynthesis in the contemporary ocean. Understanding the biological innovations that have occurred in the diatom chloroplast may provide us with explanations to the ecological success of this lineage and clues as to how best to exploit the biology of these organisms for biotechnology. In this paper, we use multi-species transcriptome datasets to compare chloroplast metabolism pathways in diatoms to other algal lineages. We identify possible diatom-specific innovations in chloroplast metabolism, including the completion of tocopherol synthesis via a chloroplast-targeted tocopherol cyclase, a complete chloroplast ornithine cycle, and chloroplast-targeted proteins involved in iron acquisition and CO2 concentration not shared between diatoms and their closest relatives in the stramenopiles. We additionally present a detailed investigation of the chloroplast metabolism of the oil-producing diatom Fistulifera solaris, which is of industrial interest for biofuel production. These include modified amino acid and pyruvate hub metabolism that might enhance acetyl-coA production for chloroplast lipid biosynthesis and the presence of a chloroplast-localised squalene synthesis pathway unknown in other diatoms. Our data provides valuable insights into the biological adaptations underpinning an ecologically critical lineage, and how chloroplast metabolism can change even at a species level in extant algae.
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20
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Jaramillo-Madrid AC, Ashworth J, Fabris M, Ralph PJ. Phytosterol biosynthesis and production by diatoms (Bacillariophyceae). PHYTOCHEMISTRY 2019; 163:46-57. [PMID: 31005802 DOI: 10.1016/j.phytochem.2019.03.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 03/22/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Diatoms are abundant unicellular marine photosynthetic algae that have genetically diversified their physiology and metabolism while adapting to numerous environments. The metabolic repertoire of diatoms presents opportunities to characterise the biosynthesis and production of new and potentially valuable microalgal compounds, including sterols. Sterols of plant origin, known as phytosterols, have been studied for health benefits including demonstrated cholesterol-lowering properties. In this review we summarise sterol diversity, the unique metabolic features of sterol biosynthesis in diatoms, and prospects for the extraction of diatom phytosterols in comparison to existing sources. We also review biotechnological efforts to manipulate diatom biosynthesis, including culture conditions and avenues for the rational engineering of metabolism and cellular regulation.
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Affiliation(s)
| | - Justin Ashworth
- Climate Change Cluster, University of Technology Sydney, Sydney, Australia.
| | - Michele Fabris
- Climate Change Cluster, University of Technology Sydney, Sydney, Australia; CSIRO Synthetic Biology Future Science Platform, PO Box 2583, Brisbane, QLD, 4001, Australia
| | - Peter J Ralph
- Climate Change Cluster, University of Technology Sydney, Sydney, Australia.
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21
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Xiao S, Ju LK. Conversion of wastewater-originated waste grease to polyunsaturated fatty acid-rich algae with phagotrophic capability. Appl Microbiol Biotechnol 2018; 103:695-705. [PMID: 30392123 DOI: 10.1007/s00253-018-9477-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/18/2018] [Accepted: 10/23/2018] [Indexed: 01/08/2023]
Abstract
Grease balls collected from a municipal wastewater treatment plant were melt-screened and used for cultivation of microalga Ochromonas danica, which could phagocytize droplets and particles as food. After autoclaving, the waste grease (WG) separated into two (upper and lower) phases. O. danica grew well on both, accumulating 48-79% (w/w) intracellular lipids. Initial WG contained approximately 50:50 triglycerides and free fatty acids (FFAs); over time, almost only FFAs remained in the extracellular WG presumably due to hydrolysis by algal lipase. PUFAs, mainly C18:2n6, C18:3n3, C18:3n6, C20:4n6, and C22:5n6, were synthesized and enriched to up to 67% of intracellular FAs, from the original 15% PUFA content in WG. The study showed feasibility of converting wastewater-originated WG to PUFA-rich O. danica algae culture, possibly as aquaculture/animal feed. WG dispersion was identified as a major processing factor to further improve for optimal WG conversion rate and cell and FA yields.
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Affiliation(s)
- Suo Xiao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH, 44325, USA
| | - Lu-Kwang Ju
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH, 44325, USA.
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22
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Zhang W, Song R, Cao B, Yang X, Wang D, Fu X, Song Y. Variations of floc morphology and extracellular organic matters (EOM) in relation to floc filterability under algae flocculation harvesting using polymeric titanium coagulants (PTCs). BIORESOURCE TECHNOLOGY 2018; 256:350-357. [PMID: 29471230 DOI: 10.1016/j.biortech.2018.02.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
The work evaluated the algae cells removal efficiency using titanium salt coagulants with different degree of polymerization (PTCs), and the algae cells aggregates and extracellular organic matter (EOM) under chemical flocculation were investigated. The results indicated that PTCs performed well in algae cells flocculation and separation. The main mechanism using PTCs of low alkalisation degree for algae flocculation was associated with charge neutralization, while adsorption bridging and sweep flocculation was mainly responsible for algae removal by PTCs of high alkalisation degree treatment. In addition, the flocs formed by PTC1.0 showed the best filtration property, and EOM reached the minimum at this time, indicating the flocs formed by PTC1.0 were more compact than other PTCs, which can be confirmed by SEM analysis. Three-dimensional excitation emission matrix fluorescence (3D-EEM) and high performance size exclusion chromatography (HPSEC) revealed that the EOMs were removed under PTCs flocculation, which improved floc filterability.
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Affiliation(s)
- Weijun Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
| | - Rongna Song
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Bingdi Cao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaofang Yang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dongsheng Wang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, Hubei, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Provincial Engineering Research Center of Systematic Water Pollution Control, Wuhan 430074, Hubei, China
| | - Xingmin Fu
- Beijing Engineering Research Center of Wastewater Resuse, Beijing 100124, China
| | - Yao Song
- Beijing Drainage Group Co. Ltd, Beijing 100124, China
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