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Usai G, Cordara A, Mazzocchi E, Re A, Fino D, Pirri CF, Menin B. Coupling dairy wastewaters for nutritional balancing and water recycling: sustainable heterologous 2-phenylethanol production by engineered cyanobacteria. Front Bioeng Biotechnol 2024; 12:1359032. [PMID: 38497052 PMCID: PMC10940361 DOI: 10.3389/fbioe.2024.1359032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
Microalgae biotechnology is hampered by the high production costs and the massive usage of water during large-volume cultivations. These drawbacks can be softened by the production of high-value compounds and by adopting metabolic engineering strategies to improve their performances and productivity. Today, the most sustainable approach is the exploitation of industrial wastewaters for microalgae cultivation, which couples valuable biomass production with water resource recovery. Among the food processing sectors, the dairy industry generates the largest volume of wastewaters through the manufacturing process. These effluents are typically rich in dissolved organic matter and nutrients, which make it a challenging and expensive waste stream for companies to manage. Nevertheless, these rich wastewaters represent an appealing resource for microalgal biotechnology. In this study, we propose a sustainable approach for high-value compound production from dairy wastewaters through cyanobacteria. This strategy is based on a metabolically engineered strain of the model cyanobacterium Synechococcus elongatus PCC 7942 (already published elsewhere) for 2-phenylethanol (2-PE). 2-PE is a high-value aromatic compound that is widely employed as a fragrance in the food and cosmetics industry thanks to its pleasant floral scent. First, we qualitatively assessed the impact of four dairy effluents on cyanobacterial growth to identify the most promising substrates. Both tank-washing water and the liquid effluent of exhausted sludge resulted as suitable nutrient sources. Thus, we created an ideal buffer system by combining the two wastewaters while simultaneously providing balanced nutrition and completely avoiding the need for fresh water. The combination of 75% liquid effluent of exhausted sludge and 25% tank-washing water with a fine-tuning ammonium supplementation yielded 180 mg L-1 of 2-PE and a biomass concentration of 0.6 gDW L-1 within 10 days. The mixture of 90% exhausted sludge and 10% washing water produced the highest yield of 2-PE (205 mg L-1) and biomass accumulation (0.7 gDW L-1), although in 16 days. Through these treatments, the phosphates were completely consumed, and nitrogen was removed in a range of 74%-77%. Overall, our approach significantly valorized water recycling and the exploitation of valuable wastewaters to circularly produce marketable compounds via microalgae biotechnology, laying a promising groundwork for subsequent implementation and scale-up.
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Affiliation(s)
- Giulia Usai
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Department of Applied Science and Technology—DISAT, Politecnico di Torino, Turin, Italy
| | - Alessandro Cordara
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Department of Environment, Land and Infrastructure Engineering—DIATI, Politecnico di Torino, Turin, Italy
| | - Elena Mazzocchi
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Department of Applied Science and Technology—DISAT, Politecnico di Torino, Turin, Italy
| | - Angela Re
- Department of Applied Science and Technology—DISAT, Politecnico di Torino, Turin, Italy
| | - Debora Fino
- Department of Applied Science and Technology—DISAT, Politecnico di Torino, Turin, Italy
| | - Candido Fabrizio Pirri
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Department of Applied Science and Technology—DISAT, Politecnico di Torino, Turin, Italy
| | - Barbara Menin
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche IBBA-CNR, Milan, Italy
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Zinicovscaia I, Safonov A, Ostalkevich S, Gundorina S, Nekhoroshkov P, Grozdov D. Metal ions removal from different type of industrial effluents using Spirulina platensis biomass. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2019; 21:1442-1448. [PMID: 31244333 DOI: 10.1080/15226514.2019.1633264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The biomass of the cyanobacterium Spirulina platensis was used for metal removal from four industrial effluents with different chemical composition. The process of metal bioaccumulation (alive biomass) and biosorption (dry biomass) was studied at the native effluents pH as well as the pH 9.5. Metal uptake by S. platensis biomass was determined by means of neutron activation analysis (NNA). The obtained results show different affinity of biomass to metals presented in effluents. The results of this study have indicated that S. platensis is a very good candidate for the removal of heavy metals from complex industrial effluents.
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Affiliation(s)
- Inga Zinicovscaia
- Joint Institute for Nuclear Research, Moscow, Russia
- Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, Bucharest, Romania
| | - Alexey Safonov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
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Lou W, Wolf BM, Blankenship RE, Liu H. Cu+ Contributes to the Orange Carotenoid Protein-Related Phycobilisome Fluorescence Quenching and Photoprotection in Cyanobacteria. Biochemistry 2019; 58:3109-3115. [DOI: 10.1021/acs.biochem.9b00409] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wenjing Lou
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Benjamin M. Wolf
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Robert E. Blankenship
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Haijun Liu
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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Engineering and characterization of copper and gold sensors in Escherichia coli and Synechococcus sp. PCC 7002. Appl Microbiol Biotechnol 2019; 103:2797-2808. [PMID: 30645690 DOI: 10.1007/s00253-018-9490-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 10/27/2018] [Indexed: 12/17/2022]
Abstract
The anthropogenic release of toxic metals into the environment poses danger to the health of both humans and the local ecosystem. Biosensors for the detection of metals have been developed to improve our ability to monitor these environmental contaminants, yet most of these sensors use heterotrophic bacterial hosts, which require a fixed carbon source and do not typically grow in natural waterways. In this study, we constructed and characterized metal sensors for development of a photoautotrophic biosensor using Synechococcus sp. PCC 7002. We characterized gold and copper sensors based on modified MerR transcriptional activators: GolSA113T, with improved gold binding, and GolSCL, containing the metal-binding loop from CueR which binds both gold and copper. The metal-sensing constructs were first optimized and characterized in Escherichia coli MG1655. The addition of a strong ribosome binding site to the optical reporter protein increased translation of the fluorescent reporter, and expression of golSA113T from the rbc promoter of Synechococcus sp. PCC 7002 improved the response to gold in MG1655. In rich medium, the GolSA113T-based E. coli sensor detected gold at concentrations as low as 100 nM, while the GolSCL-based E. coli sensor detected gold and copper at sensitivities of 100 nM and 10 μM, respectively. Both E. coli sensors responded to gold and copper yet showed no detectable response to other metals. Abiotic factors, such as medium complexity, were found to influence the response of the E. coli sensors, with minimal medium resulting in higher sensitivities of detection. Expression of the GolSA113T- and GolSCL-based sensor constructs in the cyanobacterium Synechococcus sp. PCC 7002 resulted in photoautotrophic gold sensors, but these biosensors failed to produce a significant response to copper. Moreover, the fluorescence response of the cyanobacterial sensors to gold was significantly reduced compared to that of analogous E. coli sensors. While this effort demonstrates feasibility for the development of photoautotrophic biosensors, additional efforts to optimize sensor performance will be required.
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Zhou XT, Wang F, Ma YP, Jia LJ, Liu N, Wang HY, Zhao P, Xia GX, Zhong NQ. Ectopic expression of SsPETE2, a plastocyanin from Suaeda salsa, improves plant tolerance to oxidative stress. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 268:1-10. [PMID: 29362078 DOI: 10.1016/j.plantsci.2017.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/02/2017] [Accepted: 12/09/2017] [Indexed: 05/21/2023]
Abstract
Accumulating evidence indicates that plant plastocyanin is involved in copper homeostasis, yet the physiological relevance remains elusive. In this study, we found that a plastocyanin gene (SsPETE2) from euhalophyte Suaeda salsa possessed a novel antioxidant function, which was associated with the copper-chelating activity of SsPETE2. In S. salsa, expression of SsPETE2 increased in response to oxidative stress and ectopic expression of SsPETE2 in Arabidopsis enhanced the antioxidant ability of the transgenic plants. SsPETE2 bound Cu ion and alleviated formation of hydroxyl radicals in vitro. Accordingly, SsPETE2 expression lowered the free Cu content that was associated with reduced H2O2 level under oxidative stress. Arabidopsis pete1 and pete2 mutants showed ROS-sensitive phenotypes that could be restored by expression of SsPETE2 or AtPETEs. In addition, SsPETE2-expressing plants exhibited more potent tolerance to oxidative stress than plants overexpressing AtPETEs, likely owing to the stronger copper-binding activity of SsPETE2 than AtPETEs. Taken together, these results demonstrated that plant PETEs play a novel role in oxidative stress tolerance by regulating Cu homeostasis under stress conditions, and SsPETE2, as an efficient copper-chelating PETE, potentially could be used in crop genetic engineering.
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Affiliation(s)
- Xin-Tong Zhou
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Fang Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Yin-Ping Ma
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Li-Jia Jia
- State Key Laboratory of Plant Cell and Chromosome Engineering and Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Beijing 100101, PR China
| | - Ning Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Hai-Yun Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Pan Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Gui-Xian Xia
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
| | - Nai-Qin Zhong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
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Giner-Lamia J, López-Maury L, Florencio FJ. Ni interferes in the Cu-regulated transcriptional switchpetJ/petEinSynechocystissp. PCC 6803. FEBS Lett 2016; 590:3639-3648. [DOI: 10.1002/1873-3468.12438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/09/2016] [Accepted: 09/20/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Joaquín Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis; CSIC-Universidad de Sevilla; Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis; CSIC-Universidad de Sevilla; Spain
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Zhao S, Wang X, Niu G, Dong W, Wang J, Fang Y, Lin Y, Liu L. Structural basis for copper/silver binding by theSynechocystismetallochaperone CopM. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:997-1005. [DOI: 10.1107/s2059798316011943] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/21/2016] [Indexed: 11/11/2022]
Abstract
Copper homeostasis integrates multiple processes from sensing to storage and efflux out of the cell. CopM is a cyanobacterial metallochaperone, the gene for which is located upstream of a two-component system for copper resistance, but the molecular basis for copper recognition by this four-helical bundle protein is unknown. Here, crystal structures of CopM in apo, copper-bound and silver-bound forms are reported. Monovalent copper/silver ions are buried within the bundle core; divalent copper ions are found on the surface of the bundle. The monovalent copper/silver-binding site is constituted by two consecutive histidines and is conserved in a previously functionally unknown protein family. The structural analyses show two conformational states and suggest that flexibility in the first α-helix is related to the metallochaperone function. These results also reveal functional diversity from a protein family with a simple four-helical fold.
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Released polysaccharides (RPS) from Cyanothece sp. CCY 0110 as biosorbent for heavy metals bioremediation: interactions between metals and RPS binding sites. Appl Microbiol Biotechnol 2016; 100:7765-75. [PMID: 27188779 DOI: 10.1007/s00253-016-7602-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
Abstract
Bioremediation of heavy metals using microorganisms can be advantageous compared to conventional physicochemical methods due to the use of renewable resources and efficiencies of removal particularly cations at low concentrations. In this context, cyanobacteria/cyanobacterial extracellular polymeric substances (EPS) emerge as a valid alternative due to the anionic nature and particular composition of these polymers. In this work, various culture fractions of the unicellular cyanobacterium Cyanothece sp. CCY 0110 were employed in bioremoval assays using three of the most common heavy metal pollutants in water bodies-copper, cadmium, and lead-separately or in combined systems. Our study showed that the released polysaccharides (RPS) were the most efficient fraction, removing the metal(s) by biosorption. Therefore, this polymer was subsequently used to evaluate the interactions between the metals/RPS binding sites using SEM-EDX, ICP-OES, and FTIR. Acid and basic pretreatments applied to the polymer further improve the process efficiency, and the exposure to an alkaline solution seems to alter the RPS conformation. The differences observed in the specific metal bioremoval seem to be mainly due to the RPS organic functional groups available, mainly carboxyl and hydroxyl, than to an ion exchange mechanism. Considering that Cyanothece is a highly efficient RPS-producer and that RPS can be easily separated from the culture, immobilized or confined, this polymer can be advantageous for the establishment/improvement of heavy metal removal systems.
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Effects of heavy metals on Cyanothece sp. CCY 0110 growth, extracellular polymeric substances (EPS) production, ultrastructure and protein profiles. J Proteomics 2015; 120:75-94. [DOI: 10.1016/j.jprot.2015.03.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/13/2015] [Accepted: 03/07/2015] [Indexed: 11/16/2022]
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Huertas MJ, López-Maury L, Giner-Lamia J, Sánchez-Riego AM, Florencio FJ. Metals in cyanobacteria: analysis of the copper, nickel, cobalt and arsenic homeostasis mechanisms. Life (Basel) 2014; 4:865-86. [PMID: 25501581 PMCID: PMC4284471 DOI: 10.3390/life4040865] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 11/27/2014] [Accepted: 12/04/2014] [Indexed: 11/16/2022] Open
Abstract
Traces of metal are required for fundamental biochemical processes, such as photosynthesis and respiration. Cyanobacteria metal homeostasis acquires an important role because the photosynthetic machinery imposes a high demand for metals, making them a limiting factor for cyanobacteria, especially in the open oceans. On the other hand, in the last two centuries, the metal concentrations in marine environments and lake sediments have increased as a result of several industrial activities. In all cases, cells have to tightly regulate uptake to maintain their intracellular concentrations below toxic levels. Mechanisms to obtain metal under limiting conditions and to protect cells from an excess of metals are present in cyanobacteria. Understanding metal homeostasis in cyanobacteria and the proteins involved will help to evaluate the use of these microorganisms in metal bioremediation. Furthermore, it will also help to understand how metal availability impacts primary production in the oceans. In this review, we will focus on copper, nickel, cobalt and arsenic (a toxic metalloid) metabolism, which has been mainly analyzed in model cyanobacterium Synechocystis sp. PCC 6803.
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Affiliation(s)
- María José Huertas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, E-41092 Sevilla, Spain.
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, E-41092 Sevilla, Spain.
| | - Joaquín Giner-Lamia
- Systems Biology and Bioinformatics Laboratory, IBB-CBME, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Ana María Sánchez-Riego
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, E-41092 Sevilla, Spain.
| | - Francisco Javier Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, E-41092 Sevilla, Spain.
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Giner-Lamia J, López-Maury L, Florencio FJ. Global transcriptional profiles of the copper responses in the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2014; 9:e108912. [PMID: 25268225 PMCID: PMC4182526 DOI: 10.1371/journal.pone.0108912] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/27/2014] [Indexed: 12/22/2022] Open
Abstract
Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport system, CopBAC and a protein of unknown function, CopM. Here, we report the transcriptional responses to copper additions at non-toxic (0.3 µM) and toxic concentrations (3 µM) in the wild type and in the copper sensitive copR mutant strain. While 0.3 µM copper slightly stimulated metabolism and promoted the exchange between cytochrome c6 and plastocyanin as soluble electron carriers, the addition of 3 µM copper catalyzed the formation of ROS, led to a general stress response and induced expression of Fe-S cluster biogenesis genes. According to this, a double mutant strain copRsufR, which expresses constitutively the sufBCDS operon, tolerated higher copper concentration than the copR mutant strain, suggesting that Fe-S clusters are direct targets of copper toxicity in Synechocystis. In addition we have also demonstrated that InrS, a nickel binding transcriptional repressor that belong to the CsoR family of transcriptional factor, was involved in heavy metal homeostasis, including copper, in Synechocystis. Finally, global gene expression analysis of the copR mutant strain suggested that CopRS only controls the expression of copMRS and copBAC operons in response to copper.
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Affiliation(s)
- Joaquin Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
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