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Grivalský T, Lakatos GE, Štěrbová K, Manoel JAC, Beloša R, Divoká P, Kopp J, Kriechbaum R, Spadiut O, Zwirzitz A, Trenzinger K, Masojídek J. Poly-β-hydroxybutyrate production by Synechocystis MT_a24 in a raceway pond using urban wastewater. Appl Microbiol Biotechnol 2024; 108:44. [PMID: 38180554 DOI: 10.1007/s00253-023-12924-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/16/2023] [Accepted: 10/24/2023] [Indexed: 01/06/2024]
Abstract
Poly-β-hydroxybutyrate (PHB) is a potential source of biodegradable plastics that are environmentally friendly due to their complete degradation to water and carbon dioxide. This study aimed to investigate PHB production in the cyanobacterium Synechocystis sp. PCC6714 MT_a24 in an outdoor bioreactor using urban wastewater as a sole nutrient source. The culture was grown in a thin-layer raceway pond with a working volume of 100 L, reaching a biomass density of up to 3.5 g L-1 of cell dry weight (CDW). The maximum PHB content was found under nutrient-limiting conditions in the late stationary phase, reaching 23.7 ± 2.2% PHB per CDW. These data are one of the highest reported for photosynthetic production of PHB by cyanobacteria, moreover using urban wastewater in pilot-scale cultivation which multiplies the potential of sustainable cultivation approaches. Contamination by grazers (Poterioochromonas malhamensis) was managed by culturing Synechocystis in a highly alkaline environment (pH about 10.5) which did not significantly affect the culture growth. Furthermore, the strain MT_a24 showed significant wastewater nutrient remediation removing about 72% of nitrogen and 67% of phosphorus. These trials demonstrate that the photosynthetic production of PHB by Synechocystis sp. PCC6714 MT_a24 in the outdoor thin-layer bioreactor using urban wastewater and ambient carbon dioxide. It shows a promising approach for the cost-effective and sustainable production of biodegradable carbon-negative plastics. KEY POINTS: • High PHB production by cyanobacteria in outdoor raceway pond • Urban wastewater used as a sole source of nutrients for phototrophic growth • Potential for cost-effective and sustainable production of biodegradable plastics.
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Affiliation(s)
- Tomáš Grivalský
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic.
| | - Gergely Ernő Lakatos
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
| | - Karolína Štěrbová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
| | - João Artur Câmara Manoel
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1645/31a, České Budějovice, Czech Republic
| | - Romana Beloša
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
| | - Petra Divoká
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
| | - Julian Kopp
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Division Biochemical Engineering, Getreidemarkt 9, Vienna, Austria
| | - Ricarda Kriechbaum
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Division Biochemical Engineering, Getreidemarkt 9, Vienna, Austria
| | - Oliver Spadiut
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Division Biochemical Engineering, Getreidemarkt 9, Vienna, Austria
| | - Alexander Zwirzitz
- Biosciences Research Group, University of Applied Sciences, Stelzhamerstraße 23, Wels, Austria
| | - Kevin Trenzinger
- Biosciences Research Group, University of Applied Sciences, Stelzhamerstraße 23, Wels, Austria
| | - Jiří Masojídek
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237, Třeboň, Czech Republic
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Mogany T, Bhola V, Bux F. Algal-based bioplastics: global trends in applied research, technologies, and commercialization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33644-9. [PMID: 38787471 DOI: 10.1007/s11356-024-33644-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024]
Abstract
The excessive global demand for plastic materials has resulted in severe plastic waste pollution. Conventional plastics derived from non-renewable fossil fuels are non-biodegradable, leading to significant environmental problems. Algal-based bioplastics represent a more viable, renewable, and sustainable alternative to conventional plastics. They have identical properties and characteristics as conventional plastics while being naturally biodegradable. The potential of the algal biomass value chain has already been well-established by researchers. Here, we review the novel insights on research, technology, and commercialization trends of algal-based bioplastics, encompassing macroalgae and green microalgae/cyanobacteria. Data showed that within the last decade, there has been substantial interest in utilizing microalgae for biopolymer production, with more focus on using cyanobacterial species compared to green algae. Moreover, most of the research conducted has largely focused on the production of PHA or its co-polymers. Since 2011, there have been a total of 55 patents published related to algal-based bioplastics production. To date, ~ 81 entities worldwide (commercial and private businesses) produce bioplastics from algae. Overall results of this study emphasized that even with the economic and social challenges, algae possess a substantial potential for the sustainable development of bioplastics while also addressing the UN's SDGs.
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Affiliation(s)
- Trisha Mogany
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Virthie Bhola
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa.
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Saad MH, Sidkey NM, El-Fakharany EM. Identification and statistical optimization of a novel alginate polymer extracted from newly isolated Synechocystis algini MNE ON864447 with antibacterial activity. Microb Cell Fact 2023; 22:229. [PMID: 37932753 PMCID: PMC10629183 DOI: 10.1186/s12934-023-02240-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 10/28/2023] [Indexed: 11/08/2023] Open
Abstract
Cyanobacteria are a potential source of promising secondary metabolites with different biological activities, including antibacterial, antiviral, antifungal, antiprotozoal, and anticancer activities. To combat the emergence of antibiotic resistance, there is an urgent requirement for new drugs, and cyanobacteria metabolites can constitute alternative new antibacterial medication. The chemical complexity of their exopolysaccharides indicates that they have the potential to be bioactive molecules with many biological activities. The present study aimed to produce and optimise a novel alginate polymer from a newly isolated cyanobacterium, S. algini MNE ON864447, in addition to its promising antibacterial activity. We successfully isolated a new cyanobacterium strain, S. algini MNE ON864447 from the Nile River, which produces alginate as an extracellular polymeric substance. The isolated cyanobacterial alginate was identified using a set of tests, including FTIR, TLC, HPLC, GC-MS, and 1H NMR. Plackett-Burman statistical design showed that working volume (X1), the incubation period (X2), and inoculum size (X3) are the most significant variables affecting the production of alginate. The highest alginate production (3.57 g/L) was obtained using 4% inoculum size in 400 mL medium/L conical flask after 20 days of the incubation period. The extracted alginate showed potent antibacterial activity against both Gram-negative and Gram-positive bacteria and Streptococcus mutants (NCTC10449) are the most sensitive tested pathogen for purified cyanobacterial alginate with inhibition zone diameters of 34 ± 0.1 mm at 10 mg/mL of purified alginate while Vibro cholera (NCTC 8021) the lowest sensitive one and showed inhibition zone diameters of 22.5 ± 0.05 mm at the same cyanobacterial alginate concentration. This antibacterial activity is a critical step in the development of antibacterial drugs and presents a new challenge to fight against multi-resistant bacteria.
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Affiliation(s)
- Mabroka H Saad
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research andTechnological Applications (SRTA-City), New Borg AL Arab, Alexandria, Egypt
- Botany & Microbiology Department, Faculty of Science, Al-Azhar University (Girls Branch), Cairo, Egypt
| | - Nagwa M Sidkey
- Botany & Microbiology Department, Faculty of Science, Al-Azhar University (Girls Branch), Cairo, Egypt
| | - Esmail M El-Fakharany
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research andTechnological Applications (SRTA-City), New Borg AL Arab, Alexandria, Egypt.
- Pharmaceutical and Fermentation Industries Development Centre (PFIDC), City of Scientific Research and Technological Applications (SRTA-City), New Borg Al-Arab, Alexandria, Egypt.
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Masojídek J, Lhotský R, Štěrbová K, Zittelli GC, Torzillo G. Solar bioreactors used for the industrial production of microalgae. Appl Microbiol Biotechnol 2023; 107:6439-6458. [PMID: 37725140 DOI: 10.1007/s00253-023-12733-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/21/2023]
Abstract
Microalgae are excellent sources of biomass containing several important compounds for human and animal nutrition-proteins, lipids, polysaccharides, pigments and antioxidants as well as bioactive secondary metabolites. In addition, they have a great biotechnological potential for nutraceuticals, and pharmaceuticals as well as for CO2 sequestration, wastewater treatment, and potentially also biofuel and biopolymer production. In this review, the industrial production of the most frequently used microalgae genera-Arthrospira, Chlorella, Dunaliella, Haematococcus, Nannochloropsis, Phaeodactylum, Porphyridium and several other species is discussed as concerns the applicability of the most widely used large-scale systems, solar bioreactors (SBRs)-open ponds, raceways, cascades, sleeves, columns, flat panels, tubular systems and others. Microalgae culturing is a complex process in which bioreactor operating parameters and physiological variables closely interact. The requirements of the biological system-microalgae culture are crucial to select the suitable type of SBR. When designing a cultivation process, the phototrophic production of microalgae biomass, it is necessary to employ SBRs that are adequately designed, built and operated to satisfy the physiological requirements of the selected microalgae species, considering also local climate. Moreover, scaling up microalgae cultures for commercial production requires qualified staff working out a suitable cultivation regime. KEY POINTS: • Large-scale solar bioreactors designed for microalgae culturing. • Most frequently used microalgae genera for commercial production. • Scale-up requires suitable cultivation conditions and well-elaborated protocols.
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Affiliation(s)
- Jiří Masojídek
- Laboratory of Algal Biotechnology, Centre Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czech Republic.
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
| | - Richard Lhotský
- Laboratory of Algal Biotechnology, Centre Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czech Republic
| | - Karolína Štěrbová
- Laboratory of Algal Biotechnology, Centre Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czech Republic
| | | | - Giuseppe Torzillo
- Istituto Per La Bioeconomia, CNR, Sesto Fiorentino, Florence, Italy
- Centro de Investigation en Ciencias del Mar Y Limnologia (CIMAR), Ciudad de La Investigation, Universidad de Costa Rica, San Pedro, Costa Rica
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5
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Biopolymer production in microbiology by application of metabolic engineering. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-021-03820-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nanda N, Bharadvaja N. Algal bioplastics: current market trends and technical aspects. CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY 2022; 24:2659-2679. [PMID: 35855786 PMCID: PMC9281343 DOI: 10.1007/s10098-022-02353-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
ABSTRACT Plastics are undebatably a hot topic of discussion across international forums due to their huge ecological footprint. The onset of COVID-19 pandemic has exacerbated the issue in an irreversible manner. Bioplastics produced from renewable sources are a result of lookout for sustainable alternatives. Replacing a ton of synthetic plastics with biobased ones reduces 1.8 tons CO2 emissions. Here, we begin with highlighting the problem statement-Plastic accumulation and its associated negative impacts. Microalgae outperforms plants and microbes, when used to produce bioplastic due to superior growth rate, non-competitive nature to food, and simultaneous wastewater remediation. They have minimal nutrient requirements and less dependency on climatic conditions for cultivation. These are the reasons for current boom in the algal bioplastic market. However, it is still not at par in price with the petroleum-based plastics. A brief market research has been done to better evaluate the current global status and future scope of algal bioplastics. The objective of this review is to propose possible solutions to resolve the challenges in scale up of bioplastic industry. Various bioplastic production technologies have been comprehensively discussed along with their optimization strategies. Overall studies discussed show that in order to make it cost competitive adopting a multi-dimensional approach like algal biorefinery is the best way out. A holistic comparison of any bio-based alternative with its conventional counterpart is imperative to assess its impact upon commercialization. Therefore, the review concludes with the life cycle assessment of bioplastics and measures to improve their inclusivity in a circular economy.
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Affiliation(s)
- Neha Nanda
- Plant Biotechnology Laboratory, Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi, 110042 India
| | - Navneeta Bharadvaja
- Plant Biotechnology Laboratory, Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi, 110042 India
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Rueda E, Álvarez-González A, Vila J, Díez-Montero R, Grifoll M, García J. Inorganic carbon stimulates the metabolic routes related to the polyhdroxybutyrate production in a Synechocystis sp. strain (cyanobacteria) isolated from wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 829:154691. [PMID: 35318053 DOI: 10.1016/j.scitotenv.2022.154691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Cyanobacteria are capable of transforming CO2 into polyhydroxybutyrate (PHB). In this study, different inorganic carbon concentrations (0-2 gC L-1) were evaluated for a Synechocystis sp. strain isolated from wastewater. Quantitative RT-qPCR was also performed to decipher the links between inorganic carbon and PHB and glycogen metabolism. 2 gC L-1 of bicarbonate stimulated cell growth, nutrients consumption and production of PHB. Using this concentration, a 14%dcw of PHB and an average productivity of 2.45 mgPHB L-1 d-1 were obtained. Gene expression analysis revelated that these conditions caused the overexpression of genes related to glycogen and PHB synthesis. Moreover, a positive correlation between the genes codifying for the glycogen phosphorylase, the acetyl-CoA reductase and the poly(3-hydroxyalkanoate) polymerase was found, meaning that PHB synthesis and glycogen catabolism are strongly related. These results provide an exhaustive evaluation of the effect of carbon on the PHB production and cyanobacterial metabolism.
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Affiliation(s)
- Estel Rueda
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Escola d'Enginyeria de Barcelona Est (EEBE), Universitat Politècnica de Catalunya-BarcelonaTech, Av. Eduard Maristany 16, Building C5.1, E-08019 Barcelona, Spain
| | - Ana Álvarez-González
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Joaquim Vila
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Diagonal 643, Barcelona E-08028, Spain
| | - Rubén Díez-Montero
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Magdalena Grifoll
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Diagonal 643, Barcelona E-08028, Spain
| | - Joan García
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain.
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Jo SY, Son J, Sohn YJ, Lim SH, Lee JY, Yoo JI, Park SY, Na JG, Park SJ. A shortcut to carbon-neutral bioplastic production: Recent advances in microbial production of polyhydroxyalkanoates from C1 resources. Int J Biol Macromol 2021; 192:978-998. [PMID: 34656544 DOI: 10.1016/j.ijbiomac.2021.10.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/04/2021] [Accepted: 10/09/2021] [Indexed: 12/18/2022]
Abstract
Since the 20th century, plastics that are widely being used in general life and industries are causing enormous plastic waste problems since improperly discarded plastics barely degrade and decompose. Thus, the demand for polyhydroxyalkanoates (PHAs), biodegradable polymers with material properties similar to conventional petroleum-based plastics, has been increased so far. The microbial production of PHAs is an environment-friendly solution for the current plastic crisis, however, the carbon sources for the microbial PHA production is a crucial factor to be considered in terms of carbon-neutrality. One‑carbon (C1) resources, such as methane, carbon monoxide, and carbon dioxide, are greenhouse gases and are abundantly found in nature and industry. C1 resources as the carbon sources for PHA production have a completely closed carbon loop with much advances; i) fast carbon circulation with direct bioconversion process and ii) simple fermentation procedure without sterilization as non-preferable nutrients. This review discusses the biosynthesis of PHAs based on C1 resource utilization by wild-type and metabolically engineered microbial host strains via biorefinery processes.
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Affiliation(s)
- Seo Young Jo
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Jina Son
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Yu Jung Sohn
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Seo Hyun Lim
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Ji Yeon Lee
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Jee In Yoo
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Se Young Park
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea.
| | - Si Jae Park
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea.
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Sirohi R, Lee JS, Yu BS, Roh H, Sim SJ. Sustainable production of polyhydroxybutyrate from autotrophs using CO 2 as feedstock: Challenges and opportunities. BIORESOURCE TECHNOLOGY 2021; 341:125751. [PMID: 34416655 DOI: 10.1016/j.biortech.2021.125751] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/05/2021] [Accepted: 08/07/2021] [Indexed: 05/05/2023]
Abstract
Due to industrialization and rapid increase in world population, the global energy consumption has increased dramatically. As a consequence, there is increased consumption of fossil fuels, leading to a rapid increase in CO2 concentration in the atmosphere. This accumulated CO2 can be efficiently used by autotrophs as a carbon source to produce chemicals and biopolymers. There has been increasing attention on the production of polyhydroxybutyrate (PHB), a biopolymer, with focus on reducing the production cost. For this, cheaper renewable feedstocks, molecular tools, including metabolic and genetic engineering have been explored to improve microbial strains along with process engineering aspects for scale-up of PHB production. This review discusses the recent advents on the utilization of CO2 as feedstock especially by engineered autotrophs, for sustainable production of PHB. The review also discusses the innovations in cultivation technology and process monitoring while understanding the underlying mechanisms for CO2 to biopolymer conversion.
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Affiliation(s)
- Ranjna Sirohi
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea
| | - Jeong Seop Lee
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea
| | - Byung Sun Yu
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea
| | - Hyejin Roh
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea
| | - Sang Jun Sim
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea.
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Veerabadhran M, Natesan S, MubarakAli D, Xu S, Yang F. Using different cultivation strategies and methods for the production of microalgal biomass as a raw material for the generation of bioproducts. CHEMOSPHERE 2021; 285:131436. [PMID: 34256200 DOI: 10.1016/j.chemosphere.2021.131436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/25/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Microalgal biomass and its fine chemical production from microalgae have pioneered algal bioprocess technology with few limitations such as lab-to-industry. However, laboratory-scale transitions and industrial applications are hindered by a plethora of limitations comprising expensive in culturing methods. Therefore, to emphasize the profitable benefits, the algal culturing techniques appropriately employed for large-scale microalgal biomass yield necessitates intricate assessment to emphasize the profitable benefits. The present review holistically compiles the culturing strategies for improving microalgal biomass production based on appropriate factors like designing better bioreactor designs. On the other hand, synthetic biology approaches for abridging the effective industrial transition success explored recently. Prospects in synthetic biology for enhanced microalgal biomass production based on cultivation strategies and various mechanistic modes approach to enrich cost-effective and viable output are discussed. The State-of-the-art culturing techniques encompassing enhancement of photosynthetic activity, designing bioreactor design, and potential augmenting protocols for biomass yield employing indoor cultivation in both (Open and or/closed) methods are enumerated. Further, limitations hindering the microalgal bioproducts development are critically evaluated for improving culturing techniques for microalgal cell factories, subsequently escalating the cost-benefit ratio in bioproducts synthesis from microalgae. The comprehensive analysis could provide a rational and deeper detailed insight for microalgal entrepreneurs through alternative culturing technology viz., synthetic biology and genome engineering in an Industrial perspective arena.
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Affiliation(s)
- Maruthanayagam Veerabadhran
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China.
| | - Sivakumar Natesan
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
| | - Davoodbasha MubarakAli
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India.
| | - Shuaishuai Xu
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China.
| | - Fei Yang
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical College, University of South China, Hengyang, China.
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Mittermair S, Lakatos G, Nicoletti C, Ranglová K, Manoel JC, Grivalský T, Kozhan DM, Masojídek J, Richter J. Impact of glgA1, glgA2 or glgC overexpression on growth and glycogen production in Synechocystis sp. PCC 6803. J Biotechnol 2021; 340:47-56. [PMID: 34481001 DOI: 10.1016/j.jbiotec.2021.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
Low production rates are still one limiting factor for the industrial climate-neutral production of biovaluable compounds in cyanobacteria. Next to optimized cultivation conditions, new production strategies are required. Hence, the use of established molecular tools could lead to increased product yields in the cyanobacterial model organism Synechocystis sp. PCC6803. Its main storage compound glycogen was chosen to be increased by the use of these tools. In this study, the three genes glgC, glgA1 and glgA2, which are part of the glycogen synthesis pathway, were combined with the Pcpc560 promoter and the neutral cloning site NSC1. The complete genome integration, protein formation, biomass production and glycogen accumulation were determined to select the most productive transformants. The overexpression of glgA2 did not increase the biomass or glycogen production in short-term trials compared to the other two genes but caused transformants death in long-term trials. The transformants glgA1_11 and glgC_2 showed significantly increased biomass (1.6-fold - 1.7-fold) and glycogen production (3.5-fold - 4-fold) compared to the wild type after 96 h making them a promising energy source for further applications. Those could include for example a two-stage production process, with first energy production (glycogen) and second increased product formation (e.g. ethanol).
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Affiliation(s)
- Sandra Mittermair
- Department of Biology and Chemistry, AG Biosciences, University of Applied Sciences Upper Austria, Roseggerstraße 15, 4600 Wels, Austria
| | - Gergely Lakatos
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237 - Opatovický mlýn, 37901 Třeboň, Czech Republic
| | - Cecilia Nicoletti
- Department of Biology and Chemistry, AG Biosciences, University of Applied Sciences Upper Austria, Roseggerstraße 15, 4600 Wels, Austria
| | - Karolína Ranglová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237 - Opatovický mlýn, 37901 Třeboň, Czech Republic
| | - João Câmara Manoel
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237 - Opatovický mlýn, 37901 Třeboň, Czech Republic
| | - Tomáš Grivalský
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237 - Opatovický mlýn, 37901 Třeboň, Czech Republic
| | - Daniyar Malikuly Kozhan
- Al-Farabi Kazakh National University, Faculty of Biology and Biotechnology, 71 Al-Farabi Ave., Almaty 050040, Kazakhstan
| | - Jiří Masojídek
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Algal Biotechnology, Novohradská 237 - Opatovický mlýn, 37901 Třeboň, Czech Republic
| | - Juliane Richter
- Department of Biology and Chemistry, AG Biosciences, University of Applied Sciences Upper Austria, Roseggerstraße 15, 4600 Wels, Austria.
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12
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Davies CG, Reilly K, Altermann E, Hendrickson HL. PLAN-M; Mycobacteriophage Endolysins Fused to Biodegradable Nanobeads Mitigate Mycobacterial Growth in Liquid and on Surfaces. Front Microbiol 2021; 12:562748. [PMID: 33981289 DOI: 10.3389/fmicb.2021.562748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
The Mycobacteria are a genus of Actinobacteria that include human pathogens such as Mycobacterium tuberculosis (TB). Active TB disease can spread by airborne transmission to healthcare workers and to their community. The HHMI SEA-PHAGES program has contributed to discovering bacteriophages that are able to infect M. smegmatis MC2 155, a close relative of M. tuberculosis. This collection of diverse Mycobacteriophages is an excellent resource for trialling bacteriophage-sourced enzymes in novel applications. Herein we measured the ability Mycobacteriophage endolysins to lyse their host strain when functionally fused to biodegradable polyhydroxyalkanoate (PHA) nanobeads. PHA nanobeads facilitate both the expression and the application of enzymes to surfaces and have been demonstrated to stabilize a wide array of proteins for practical applications whilst eliminating the challenges of traditional protein purification. We selected two Lysin A and six Lysin B homologs to be functionally fused to the polyhydroxyalkanoate synthase C (PhaC). Expression of these constructs resulted in functional lysins displayed on the surface of PHA nanobeads. The lysins thus directionally displayed on nanobeads lysed up to 79% of the M. smegmatis MC2 155 population using 80 mg/mL of nanobeads in pure culture. In order to determine whether the nanobeads would be effective as a protective layer in PPE we adapted a fabric-based test and observed a maximum of 1 log loss of the cell population after 5 h of exposure on a textile (91% cell lysis). Lysin B enzymes performed better than the Lysin A enzymes as a protective barrier on textiles surface assays. These results suggest that bacterial endolysins are efficient in their action when displayed on PHA nanobeads and can cause significant population mortality in as little as 45 min. Our results provide the proof-of-principle that Mycobacteriophage endolysins can be used on functionalized nanobeads where they can protect surfaces such as personal protective equipment (PPE) that routinely come into contact with aerosolised bacteria.
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Affiliation(s)
- Courtney G Davies
- Massey Phage Whānau, School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | | | - Eric Altermann
- AgResearch Ltd., Palmerston North, New Zealand.,Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Heather L Hendrickson
- Massey Phage Whānau, School of Natural and Computational Sciences, Massey University, Auckland, New Zealand.,Infectious Disease Research Centre, Massey University, Palmerston North, New Zealand
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13
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Obulisamy PK, Mehariya S. Polyhydroxyalkanoates from extremophiles: A review. BIORESOURCE TECHNOLOGY 2021; 325:124653. [PMID: 33465644 DOI: 10.1016/j.biortech.2020.124653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/27/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
Polyhydroxyalkanoates (PHAs) are group monomers/heteropolymers that are biodegradable and widely used in biomedical applications. They are considered as alternatives to fossil derived polymers and accumulated by microbes including extremophilic archaea as energy storage inclusions under nutrient limitations. The use of extremophilic archaea for PHA production is an economically viable option for conventional aerobic processes, but less is known about their pathways and PHA accumulation capacities. This review summarized: (a) specific adaptive mechanisms towards extreme environments by extremophiles and specific role of PHAs; (b) understanding of PHA synthesis/metabolism in archaea and specific functional genes; (c) genetic engineering and process engineering approaches required for high-rate PHA production using extremophilic archaea. To conclude, the future studies are suggested to understand the membrane lipids and PHAs accumulation to explain the adaptation mechanism of extremophiles and exploiting it for commercial production of PHAs.
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Affiliation(s)
| | - Sanjeet Mehariya
- Department of Engineering, University of Campania "Luigi Vanvitelli", Real Casa dell'Annunziata, Italy
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14
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Amadu AA, Qiu S, Ge S, Addico GND, Ameka GK, Yu Z, Xia W, Abbew AW, Shao D, Champagne P, Wang S. A review of biopolymer (Poly-β-hydroxybutyrate) synthesis in microbes cultivated on wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143729. [PMID: 33310224 DOI: 10.1016/j.scitotenv.2020.143729] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
The large quantities of non-degradable single use plastics, production and disposal, in addition to increasing amounts of municipal and industrial wastewaters are among the major global issues known today. Biodegradable plastics from biopolymers such as Poly-β-hydroxybutyrates (PHB) produced by microorganisms are potential substitutes for non-degradable petroleum-based plastics. This paper reviews the current status of wastewater-cultivated microbes utilized in PHB production, including the various types of wastewaters suitable for either pure or mixed culture PHB production. PHB-producing strains that have the potential for commercialization are also highlighted with proposed selection criteria for choosing the appropriate PHB microbe for optimization of processes. The biosynthetic pathways involved in producing microbial PHB are also discussed to highlight the advancements in genetic engineering techniques. Additionally, the paper outlines the factors influencing PHB production while exploring other metabolic pathways and metabolites simultaneously produced along with PHB in a bio-refinery context. Furthermore, the paper explores the effects of extraction methods on PHB yield and quality to ultimately facilitate the commercial production of biodegradable plastics. This review uniquely discusses the developments in research on microbial biopolymers, specifically PHB and also gives an overview of current commercial PHB companies making strides in cutting down plastic pollution and greenhouse gases.
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Affiliation(s)
- Ayesha Algade Amadu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China.
| | - Gloria Naa Dzama Addico
- Council for Scientific and Industrial Research (CSIR) - Water Research Institute (WRI), P.O. Box AH 38, Achimota Greater Accra, Ghana
| | - Gabriel Komla Ameka
- Department of Botany, University of Ghana, P.O. Box LG55, Legon, Accra, Ghana
| | - Ziwei Yu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Wenhao Xia
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Abdul-Wahab Abbew
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Dadong Shao
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Pascale Champagne
- Department of Civil Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Sufeng Wang
- School of Economics and Management, Anhui Jianzhu University, Hefei, Anhui 230601, PR China
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15
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Afreen R, Tyagi S, Singh GP, Singh M. Challenges and Perspectives of Polyhydroxyalkanoate Production From Microalgae/Cyanobacteria and Bacteria as Microbial Factories: An Assessment of Hybrid Biological System. Front Bioeng Biotechnol 2021; 9:624885. [PMID: 33681160 PMCID: PMC7933458 DOI: 10.3389/fbioe.2021.624885] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/29/2021] [Indexed: 11/13/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are the biopolymer of choice if we look for a substitute of petroleum-based non-biodegradable plastics. Microbial production of PHAs as carbon reserves has been studied for decades and PHAs are gaining attention for a wide range of applications in various fields. Still, their uneconomical production is the major concern largely attributed to high cost of organic substrates for PHA producing heterotrophic bacteria. Therefore, microalgae/cyanobacteria, being photoautotrophic, prove to have an edge over heterotrophic bacteria. They have minimal metabolic requirements, such as inorganic nutrients (CO2, N, P, etc.) and light, and they can survive under adverse environmental conditions. PHA production under photoautotrophic conditions has been reported from cyanobacteria, the only candidate among prokaryotes, and few of the eukaryotic microalgae. However, an efficient cultivation system is still required for photoautotrophic PHA production to overcome the limitations associated with (1) stringent management of closed photobioreactors and (2) optimization of monoculture in open pond culture. Thus, a hybrid system is a necessity, involving the participation of microalgae/cyanobacteria and bacteria, i.e., both photoautotrophic and heterotrophic components having mutual interactive benefits for each other under different cultivation regime, e.g., mixotrophic, successive two modules, consortium based, etc. Along with this, further strategies like optimization of culture conditions (N, P, light exposure, CO2 dynamics, etc.), bioengineering, efficient downstream processes, and the application of mathematical/network modeling of metabolic pathways to improve PHA production are the key areas discussed here. Conclusively, this review aims to critically analyze cyanobacteria as PHA producers and proposes economically sustainable production of PHA from microbial autotrophs and heterotrophs in "hybrid biological system."
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Affiliation(s)
- Rukhsar Afreen
- Department of Zoology, Gargi College, University of Delhi, New Delhi, India
| | - Shivani Tyagi
- Department of Zoology, Gargi College, University of Delhi, New Delhi, India
| | - Gajendra Pratap Singh
- Mathematical Sciences and Interdisciplinary Research Lab (Math Sci Int R-Lab), School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Mamtesh Singh
- Department of Zoology, Gargi College, University of Delhi, New Delhi, India
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Mittermair S, Richter J, Doppler P, Trenzinger K, Nicoletti C, Forsich C, Spadiut O, Herwig C, Lackner M. Impact ofexoDgene knockout on the polyhydroxybutyrate overaccumulating mutant Mt_a24. INTERNATIONAL JOURNAL OF BIOBASED PLASTICS 2021. [DOI: 10.1080/24759651.2020.1863020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Sandra Mittermair
- Department of Chemistry and Biology, University of Applied Sciences Upper Austria, AG Biosciences , Wels, Austria
| | - Juliane Richter
- Department of Chemistry and Biology, University of Applied Sciences Upper Austria, AG Biosciences , Wels, Austria
| | - Philipp Doppler
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien , Vienna, Austria
| | - Kevin Trenzinger
- Department of Chemistry and Biology, University of Applied Sciences Upper Austria, AG Biosciences , Wels, Austria
| | - Cecilia Nicoletti
- Department of Chemistry and Biology, University of Applied Sciences Upper Austria, AG Biosciences , Wels, Austria
| | - Christian Forsich
- Department of Materials Technology, University of Applied Sciences Upper Austria , Wels, Austria
| | - Oliver Spadiut
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien , Vienna, Austria
| | - Christoph Herwig
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien , Vienna, Austria
| | - Maximilian Lackner
- Lackner Ventures & Consulting GmbH , Vienna, Austria
- University of Applied Sciences Technikum Wien , Vienna, Austria
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17
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Koch M, Bruckmoser J, Scholl J, Hauf W, Rieger B, Forchhammer K. Maximizing PHB content in Synechocystis sp. PCC 6803: a new metabolic engineering strategy based on the regulator PirC. Microb Cell Fact 2020; 19:231. [PMID: 33353555 PMCID: PMC7756911 DOI: 10.1186/s12934-020-01491-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/02/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PHB (poly-hydroxy-butyrate) represents a promising bioplastic alternative with good biodegradation properties. Furthermore, PHB can be produced in a completely carbon-neutral fashion in the natural producer cyanobacterium Synechocystis sp. PCC 6803. This strain has been used as model system in past attempts to boost the intracellular production of PHB above ~ 15% per cell-dry-weight (CDW). RESULTS We have created a new strain that lacks the regulatory protein PirC (product of sll0944), which exhibits a higher activity of the phosphoglycerate mutase resulting in increased PHB pools under nutrient limiting conditions. To further improve the intracellular PHB content, two genes involved in PHB metabolism, phaA and phaB, from the known producer strain Cupriavidus necator, were introduced under the control of the strong promotor PpsbA2. The resulting strain, termed PPT1 (ΔpirC-REphaAB), produced high amounts of PHB under continuous light as well under a day-night regime. When grown in nitrogen and phosphorus depleted medium, the cells produced up to 63% per CDW. Upon the addition of acetate, the content was further increased to 81% per CDW. The produced polymer consists of pure PHB, which is highly isotactic. CONCLUSION The amounts of PHB achieved with PPT1 are the highest ever reported in any known cyanobacterium and demonstrate the potential of cyanobacteria for a sustainable, industrial production of PHB.
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Affiliation(s)
- Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Jonas Bruckmoser
- Wacker-Chair of Macromolecular Chemistry, TUM Department of Chemistry, Technical University of Munich, Munich, Germany
| | - Jörg Scholl
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Waldemar Hauf
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Bernhard Rieger
- Wacker-Chair of Macromolecular Chemistry, TUM Department of Chemistry, Technical University of Munich, Munich, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
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18
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Exopolysaccharides from Cyanobacteria: Strategies for Bioprocess Development. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10113763] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cyanobacteria have the potential to become an industrially sustainable source of functional biopolymers. Their exopolysaccharides (EPS) harbor chemical complexity, which predicts bioactive potential. Although some are reported to excrete conspicuous amounts of polysaccharides, others are still to be discovered. The production of this strain-specific trait can promote carbon neutrality while its intrinsic location can potentially reduce downstream processing costs. To develop an EPS cyanobacterial bioprocess (Cyano-EPS) three steps were explored: the selection of the cyanobacterial host; optimization of production parameters; downstream processing. Studying the production parameters allow us to understand and optimize their response in terms of growth and EPS production though many times it was found divergent. Although the extraction of EPS can be achieved with a certain degree of simplicity, the purification and isolation steps demand experience. In this review, we gathered relevant research on EPS with a focus on bioprocess development. Challenges and strategies to overcome possible drawbacks are highlighted.
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Advances in Polyhydroxyalkanoate (PHA) Production, Volume 2. Bioengineering (Basel) 2020; 7:bioengineering7010024. [PMID: 32143303 PMCID: PMC7148466 DOI: 10.3390/bioengineering7010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/02/2020] [Indexed: 01/29/2023] Open
Abstract
During the two years that have passed since the first volume of “Advances in Polyhydroxyalkanoate (PHA) production” was published, the progress in PHA-related research was indeed tremendous, calling for the next, highly bioprocess- and bioengineering-oriented volume. This editorial paper summarizes and puts into context the contributions to this second volume of the Bioengineering Special Issue; it covers highly topical fields of PHA-related R&D activities, covering, beside the pronounced bioengineering-related articles, the fields of the microbiology of underexplored, but probably emerging, PHA production strains from the groups of Pseudomonas, cyanobacteria, methanotrophs, and from the extremophilic domain of haloarchaea. Moreover, novel second-generation lignocellulose feedstocks for PHA production from agriculture to be used in biorefinery concepts, new approaches for fine-tuning the composition of PHA co- and terpolyesters, process simulation for PHA production from methane-rich natural gas, the challenges associated with rheology-governed oxygen transfer in high cell density cultivations, rapid spectroscopic in-line analytics for process monitoring, and the biomedical application of PHA biopolyesters after appropriate advanced processing are the subjects of the presented studies.
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Exploitation of Wheat Straw Biorefinery Side Streams as Sustainable Substrates for Microorganisms: A Feasibility Study. Processes (Basel) 2019. [DOI: 10.3390/pr7120956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Lignocellulosic agricultural side products, like wheat straw, are widely seen as an important contribution to a future sustainable economy. However, optimization of biorefinery processes and exploitation of all side streams are crucial for an economically viable biorefinery. Pretreatment of lignocellulosic raw material, which is necessary for further processing steps, can generate low-value side streams. In this feasibility study, side streams from a liquid hot water (LHW) pretreatment of wheat straw were utilized for the production of polyhydroxybutyrate (PHB) and highly valuable tetraether lipids (TELs). Additional value created by these products can benefit the biorefinery’s economic operation. The utilized wheat straw was pretreated at 120 °C and 170 °C for up to two hours in laboratory and lab scale. The resulting side stream consists mainly of carbohydrates from hemicelluloses and fermentation inhibitors such as acetic acid. In order to achieve a successful production of both products, an acetic acid separation via distillation was necessary. Subsequently, the acetic acid fraction was utilized for the PHB production using cyanobacteria. The carbohydrate-rich fraction was applied in the cultivation of Sulfolobus acidocaldarius and resulted in the successful production of TELs. Both fractions achieved better fermentation yields compared to their corresponding reference media.
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Foong CP, Higuchi-Takeuchi M, Numata K. Optimal iron concentrations for growth-associated polyhydroxyalkanoate biosynthesis in the marine photosynthetic purple bacterium Rhodovulum sulfidophilum under photoheterotrophic condition. PLoS One 2019; 14:e0212654. [PMID: 31034524 PMCID: PMC6488045 DOI: 10.1371/journal.pone.0212654] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/17/2019] [Indexed: 01/02/2023] Open
Abstract
Polyhydroxyalkanoates (PHAs) are a group of natural biopolyesters that resemble petroleum-derived plastics in terms of physical properties but are less harmful biologically to the environment and humans. Most of the current PHA producers are heterotrophs, which require expensive feeding materials and thus contribute to the high price of PHAs. Marine photosynthetic bacteria are promising alternative microbial cell factories for cost-effective, carbon neutral and sustainable production of PHAs. In this study, Rhodovulum sulfidophilum, a marine photosynthetic purple nonsulfur bacterium with a high metabolic versatility, was evaluated for cell growth and PHA production under the influence of various media components found in previous studies. We evaluated iron, using ferric citrate, as another essential factor for cell growth and efficient PHA production and confirmed that PHA production in R. sulfidophilum was growth-associated under microaerobic and photoheterotrophic conditions. In fact, a subtle amount of iron (1 to 2 μM) was sufficient to promote rapid cell growth and biomass accumulation, as well as a high PHA volumetric productivity during the logarithmic phase. However, an excess amount of iron did not enhance the growth rate or PHA productivity. Thus, we successfully confirmed that an optimum concentration of iron, an essential nutrient, promotes cell growth in R. sulfidophilum and also enhances PHA utilization.
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Affiliation(s)
- Choon Pin Foong
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
| | - Mieko Higuchi-Takeuchi
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
| | - Keiji Numata
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
- * E-mail:
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