1
|
Dennis G, Posewitz MC. Advances in light system engineering across the phototrophic spectrum. Front Plant Sci 2024; 15:1332456. [PMID: 38410727 PMCID: PMC10895028 DOI: 10.3389/fpls.2024.1332456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/24/2024] [Indexed: 02/28/2024]
Abstract
Current work in photosynthetic engineering is progressing along the lines of cyanobacterial, microalgal, and plant research. These are interconnected through the fundamental mechanisms of photosynthesis and advances in one field can often be leveraged to improve another. It is worthwhile for researchers specializing in one or more of these systems to be aware of the work being done across the entire research space as parallel advances of techniques and experimental approaches can often be applied across the field of photosynthesis research. This review focuses on research published in recent years related to the light reactions of photosynthesis in cyanobacteria, eukaryotic algae, and plants. Highlighted are attempts to improve photosynthetic efficiency, and subsequent biomass production. Also discussed are studies on cross-field heterologous expression, and related work on augmented and novel light capture systems. This is reviewed in the context of translatability in research across diverse photosynthetic organisms.
Collapse
Affiliation(s)
- Galen Dennis
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| |
Collapse
|
2
|
LaPanse AJ, Krishnan A, Dennis G, Karns DAJ, Dahlin LR, Van Wychen S, Burch TA, Guarnieri MT, Weissman JC, Posewitz MC. Proximate biomass characterization of the high productivity marine microalga Picochlorum celeri TG2. Plant Physiol Biochem 2024; 207:108364. [PMID: 38232496 DOI: 10.1016/j.plaphy.2024.108364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/23/2023] [Accepted: 01/10/2024] [Indexed: 01/19/2024]
Abstract
Microalgae are compelling renewable resources with applications including biofuels, bioplastics, nutrient supplements, and cosmetic products. Picochlorum celeri is an alga with high industrial interest due to exemplary outdoor areal biomass productivities in seawater. Detailed proximate analysis is needed in multiple environmental conditions to understand the dynamic biomass compositions of P. celeri, and how these compositions might be leveraged in biotechnological applications. In this study, biomass characterization of P. celeri was performed under nutrient-replete, nitrogen-restricted, and hyper-saline conditions. Nutrient-replete cultivation of P. celeri resulted in protein-rich biomass (∼50% ash-free dry weight) with smaller carbohydrate (∼12% ash-free dry weight) and lipid (∼11% ash-free dry weight) partitions. Gradual nitrogen depletion elicited a shift from proteins to carbohydrates (∼50% ash-free dry weight, day 3) as cells transitioned into the production of storage metabolites. Importantly, dilutions in nitrogen-restricted 40 parts per million (1.43 mM nitrogen) media generated high-carbohydrate (∼50% ash-free dry weight) biomass without substantially compromising biomass productivity (36 g ash-free dry weight m-2 day-1) despite decreased chlorophyll (∼2% ash-free dry weight) content. This strategy for increasing carbohydrate content allowed for the targeted production of polysaccharides, which could potentially be utilized to produce fuels, oligosaccharides, and bioplastics. Cultivation at 2X sea salts resulted in a shift towards carbohydrates from protein, with significantly increased levels of the amino acid proline, which putatively acts as an osmolyte. A detailed understanding of the biomass composition of P. celeri in nutrient-replete, nitrogen-restricted, and hyper saline conditions informs how this strain can be useful in the production of biotechnological products.
Collapse
Affiliation(s)
- Alaina J LaPanse
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA.
| | - Anagha Krishnan
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Galen Dennis
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Devin A J Karns
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Lukas R Dahlin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Stefanie Van Wychen
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Tyson A Burch
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Michael T Guarnieri
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Joseph C Weissman
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| |
Collapse
|
3
|
Cano M, Krishnan A, Karns DA, Likhogrud MA, Weissman JC, Posewitz MC. Cas9 deletion of lutein biosynthesis in the marine alga Picochlorum celeri reduces photosynthetic pigments while sustaining high biomass productivity. Front Bioeng Biotechnol 2024; 11:1332461. [PMID: 38274009 PMCID: PMC10808502 DOI: 10.3389/fbioe.2023.1332461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024] Open
Abstract
Domestication of algae for food and renewable biofuels remains limited by the low photosynthetic efficiencies of processes that have evolved to be competitive for optimal light capture, incentivizing the development of large antennas in light-limiting conditions, thus decreasing efficient light utilization in cultivated ponds or photobioreactors. Reducing the pigment content to improve biomass productivity has been a strategy discussed for several decades and the ability to reduce pigment significantly is now fully at hand thanks to the widespread use of genome editing tools. Picochlorum celeri is one of the fastest growing marine algae identified and holds particular promise for outdoor cultivation, especially in saline water and warm climates. We show that while chlorophyll b is essential to sustain high biomass productivities under dense cultivation, removing Picochlorum celeri's main carotenoid, lutein, leads to a decreased total chlorophyll content, higher a/b ratio, reduced functional LHCII cross section and higher maximum quantum efficiencies at lower light intensities, resulting in an incremental increase in biomass productivity and increased PAR-to-biomass conversion efficiency. These findings further strengthen the existing strategies to improve photosynthetic efficiency and biomass production in algae.
Collapse
Affiliation(s)
- Melissa Cano
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Anagha Krishnan
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Devin A. Karns
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Maria A. Likhogrud
- ExxonMobil Technology and Engineering Company, Annandale, NJ, United States
| | - Joseph C. Weissman
- ExxonMobil Technology and Engineering Company, Annandale, NJ, United States
| | - Matthew C. Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| |
Collapse
|
4
|
Krishnan A, Cano M, Karns DA, Burch TA, Likhogrud M, Aqui M, Bailey S, Verruto J, Lambert W, Kuzminov F, Naghipor M, Wang Y, Ebmeier CC, Weissman JC, Posewitz MC. Simultaneous CAS9 editing of cp SRP43, LHCA6, and LHCA7 in Picochlorum celeri lowers chlorophyll levels and improves biomass productivity. Plant Direct 2023; 7:e530. [PMID: 37711644 PMCID: PMC10497401 DOI: 10.1002/pld3.530] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/03/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023]
Abstract
High cellular pigment levels in dense microalgal cultures contribute to excess light absorption. To improve photosynthetic yields in the marine microalga Picochlorum celeri, CAS9 gene editing was used to target the molecular chaperone cpSRP43. Depigmented strains (>50% lower chlorophyll) were generated, with proteomics showing attenuated levels of most light harvesting complex (LHC) proteins. Gene editing generated two types of cpSRP43 transformants with distinct lower pigment phenotypes: (i) a transformant (Δsrp43) with both cpSRP43 diploid alleles modified to encode non-functional polypeptides and (ii) a transformant (STR30309) with a 3 nt in-frame insertion in one allele at the CAS9 cut site (non-functional second allele), leading to expression of a modified cpSRP43. STR30309 has more chlorophyll than Δsrp43 but substantially less than wild type. To further decrease light absorption by photosystem I in STR30309, CAS9 editing was used to stack in disruptions of both LHCA6 and LHCA7 to generate STR30843, which has higher (5-24%) productivities relative to wild type in solar-simulating bioreactors. Maximal productivities required frequent partial harvests throughout the day. For STR30843, exemplary diel bioreactor yields of ~50 g m-2 day-1 were attained. Our results demonstrate diel productivity gains in P. celeri by lowering pigment levels.
Collapse
Affiliation(s)
- Anagha Krishnan
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Melissa Cano
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Devin A. Karns
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Tyson A. Burch
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Maria Likhogrud
- ExxonMobil Technology and Engineering CompanyAnnandaleNew JerseyUSA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Saroussi S, Redekop P, Karns DAJ, Thomas DC, Wittkopp TM, Posewitz MC, Grossman AR. Restricting electron flow at cytochrome b6f when downstream electron acceptors are severely limited. Plant Physiol 2023; 192:789-804. [PMID: 36960590 PMCID: PMC10231464 DOI: 10.1093/plphys/kiad185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
Photosynthetic organisms frequently experience abiotic stress that restricts their growth and development. Under such circumstances, most absorbed solar energy cannot be used for CO2 fixation and can cause the photoproduction of reactive oxygen species (ROS) that can damage the photosynthetic reaction centers of PSI and PSII, resulting in a decline in primary productivity. This work describes a biological "switch" in the green alga Chlamydomonas reinhardtii that reversibly restricts photosynthetic electron transport (PET) at the cytochrome b6f (Cyt b6f) complex when the capacity for accepting electrons downstream of PSI is severely limited. We specifically show this restriction in STARCHLESS6 (sta6) mutant cells, which cannot synthesize starch when they are limited for nitrogen (growth inhibition) and subjected to a dark-to-light transition. This restriction represents a form of photosynthetic control that causes diminished electron flow to PSI and thereby prevents PSI photodamage but does not appear to rely on a ΔpH. Furthermore, when electron flow is restricted, the plastid alternative oxidase (PTOX) becomes active, functioning as an electron valve that dissipates some excitation energy absorbed by PSII and allows the formation of a proton motive force (PMF) that would drive some ATP production (potentially sustaining PSII repair and nonphotochemical quenching [NPQ]). The restriction at the Cyt b6f complex can be gradually relieved with continued illumination. This study provides insights into how PET responds to a marked reduction in availability of downstream electron acceptors and the protective mechanisms involved.
Collapse
Affiliation(s)
- Shai Saroussi
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A J Karns
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Dylan C Thomas
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| |
Collapse
|
6
|
Huang W, Krishnan A, Plett A, Meagher M, Linka N, Wang Y, Ren B, Findinier J, Redekop P, Fakhimi N, Kim RG, Karns DA, Boyle N, Posewitz MC, Grossman AR. Chlamydomonas mutants lacking chloroplast TRIOSE PHOSPHATE TRANSPORTER3 are metabolically compromised and light-sensitive. Plant Cell 2023:koad095. [PMID: 36970811 DOI: 10.1093/plcell/koad095] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/08/2023] [Accepted: 03/23/2023] [Indexed: 06/18/2023]
Abstract
Modulation of photoassimilate export from the chloroplast is essential for controlling the distribution of fixed carbon in the cell and maintaining optimum photosynthetic rates. In this study we identified chloroplast TRIOSE PHOSPHATE/PHOSPHATE TRANSLOCATOR2 (CreTPT2) and CreTPT3 in the green alga Chlamydomonas (Chlamydomonas reinhardtii), which exhibit similar substrate specificities but whose encoding genes are differentially expressed over the diurnal cycle. We focused mostly on CreTPT3 because of its high level of expression and the severe phenotype exhibited by tpt3 relative to tpt2 mutants. Null mutants for CreTPT3 had a pleiotropic phenotype that affected growth, photosynthetic activities, metabolite profiles, carbon partitioning, and organelle-specific accumulation of H2O2. These analyses demonstrated that CreTPT3 is a dominant conduit on the chloroplast envelope for the transport of photoassimilates. In addition, CreTPT3 can serve as a safety valve that moves excess reductant out of the chloroplast and appears to be essential for preventing cells from experiencing oxidative stress and accumulating reactive oxygen species, even under low/moderate light intensities. Finally, our studies indicate subfunctionalization of the CreTPT transporters and suggest that there are differences in managing the export of photoassimilates from the chloroplasts of Chlamydomonas and vascular plants.
Collapse
Affiliation(s)
- Weichao Huang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Anagha Krishnan
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Anastasija Plett
- Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Michelle Meagher
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Nicole Linka
- Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Yongsheng Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
- School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Bijie Ren
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Justin Findinier
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Neda Fakhimi
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Rick G Kim
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A Karns
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Nanette Boyle
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| |
Collapse
|
7
|
LaPanse AJ, Burch TA, Tamburro JM, Traller JC, Pinowska A, Posewitz MC. Adaptive laboratory evolution for increased temperature tolerance of the diatom Nitzschia inconspicua. Microbiologyopen 2022; 12:e1343. [PMID: 36825881 PMCID: PMC9791160 DOI: 10.1002/mbo3.1343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/13/2022] [Indexed: 12/27/2022] Open
Abstract
Outdoor microalgal cultivation for the production of valuable biofuels and bioproducts typically requires high insolation and strains with high thermal (>37°C) tolerance. While some strains are naturally thermotolerant, other strains of interest require improved performance at elevated temperatures to enhance industrial viability. In this study, adaptive laboratory evolution (ALE) was performed for over 300 days using consecutive 0.5°C temperature increases in a constant temperature incubator to attain greater thermal tolerance in the industrially relevant diatom Nitzschia inconspicua str. Hildebrandi. The adapted strain was able to grow at a constant temperature of 37.5°C; whereas this constant temperature was lethal to the parental control, which had an upper-temperature boundary of 35.5°C before adaptive evolution. Several high-temperature clonal isolates were obtained from the evolved population following ALE, and increased temperature tolerance was observed in the clonal, parent, and non-clonal adapted cultures. This ALE method demonstrates the development of enhanced industrial algal strains without the production of genetically modified organisms (GMOs).
Collapse
Affiliation(s)
| | - Tyson A. Burch
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Jacob M. Tamburro
- Department of Quantitative Biosciences and EngineeringColorado School of MinesGoldenColoradoUSA
| | | | | | | |
Collapse
|
8
|
Davies FK, Fricker AD, Robins MM, Dempster TA, McGowen J, Charania M, Beliaev AS, Lindemann SR, Posewitz MC. Microbiota associated with the large-scale outdoor cultivation of the cyanobacterium Synechococcus sp. PCC 7002. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
9
|
Hulatt CJ, Wijffels RH, Posewitz MC. The Genome of the Haptophyte Diacronema lutheri (Pavlova lutheri, Pavlovales): A Model for Lipid Biosynthesis in Eukaryotic Algae. Genome Biol Evol 2021; 13:6337978. [PMID: 34343248 PMCID: PMC8379373 DOI: 10.1093/gbe/evab178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 12/28/2022] Open
Abstract
Haptophytes are biogeochemically and industrially important protists with underexplored genomic diversity. We present a nuclear genome assembly for the class Pavlovales, which was assembled with PacBio long-read data into highly contiguous sequences. We sequenced strain Diacronema lutheri NIVA-4/92, formerly known as Pavlova lutheri, because it has established roles in aquaculture and has been a key organism for studying microalgal lipid biosynthesis. Our data show that D. lutheri has the smallest and most streamlined haptophycean genome assembled to date, with an assembly size of 43.503 Mb and 14,446 protein-coding genes. Together with its high nuclear GC content, Diacronema is an important genus for investigating selective pressures on haptophyte genome evolution, contrasting with the much larger and more repetitive genome of the coccolithophore Emiliania huxleyi. The D. lutheri genome will be a valuable resource for resolving the genetic basis of algal lipid biosynthesis and metabolic remodeling that takes place during adaptation and stress response in natural and engineered environments.
Collapse
Affiliation(s)
- Chris J Hulatt
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
| | - René H Wijffels
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Bioprocess Engineering, AlgaePARC, Wageningen University and Research, The Netherlands
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
| |
Collapse
|
10
|
|
11
|
Krishnan A, Cano M, Burch TA, Weissman JC, Posewitz MC. Genome editing using Cas9-RNA ribonucleoprotein complexes in the high-productivity marine alga Picochlorum celeri. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101944] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
12
|
Hulatt CJ, Wijffels RH, Viswanath K, Posewitz MC. The complete mitogenome and plastome of the haptophyte Pavlova lutheri NIVA-4/92. Mitochondrial DNA B Resour 2020; 5:2748-2749. [PMID: 33457933 PMCID: PMC7782304 DOI: 10.1080/23802359.2020.1788436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The complete mitochondrial and plastid genomes of the microalga Pavlova lutheri strain NIVA-4/92 are reported. The circular-mapping mitogenome is 36,202 bp in length, contains 22 protein-coding genes, 24 tRNAs, and has a GC content of 37.5%. Like other haptophytes the mitogenome contains a single large, complex repeat region of approximately 5.4 kbp. The plastome is 95,281 bp in length and has a GC content of 35.6%. It contains 111 protein-coding genes and 27 tRNAs.
Collapse
Affiliation(s)
- Chris J Hulatt
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Department of Chemistry, Colorado School of Mines, Golden, CO, USA
| | - René H Wijffels
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Bioprocess Engineering, AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
| | - Kiron Viswanath
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway
| | | |
Collapse
|
13
|
Dahlin LR, Gerritsen AT, Henard CA, Van Wychen S, Linger JG, Kunde Y, Hovde BT, Starkenburg SR, Posewitz MC, Guarnieri MT. Development of a high-productivity, halophilic, thermotolerant microalga Picochlorum renovo. Commun Biol 2019; 2:388. [PMID: 31667362 PMCID: PMC6811619 DOI: 10.1038/s42003-019-0620-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/10/2019] [Indexed: 01/21/2023] Open
Abstract
Microalgae are promising biocatalysts for applications in sustainable fuel, food, and chemical production. Here, we describe culture collection screening, down-selection, and development of a high-productivity, halophilic, thermotolerant microalga, Picochlorum renovo. This microalga displays a rapid growth rate and high diel biomass productivity (34 g m-2 day-1), with a composition well-suited for downstream processing. P. renovo exhibits broad salinity tolerance (growth at 107.5 g L-1 salinity) and thermotolerance (growth up to 40 °C), beneficial traits for outdoor cultivation. We report complete genome sequencing and analysis, and genetic tool development suitable for expression of transgenes inserted into the nuclear or chloroplast genomes. We further evaluate mechanisms of halotolerance via comparative transcriptomics, identifying novel genes differentially regulated in response to high salinity cultivation. These findings will enable basic science inquiries into control mechanisms governing Picochlorum biology and lay the foundation for development of a microalga with industrially relevant traits as a model photobiology platform.
Collapse
Affiliation(s)
- Lukas R. Dahlin
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401 USA
| | - Alida T. Gerritsen
- Computational Science Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Calvin A. Henard
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Stefanie Van Wychen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Jeffrey G. Linger
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Yuliya Kunde
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - Blake T. Hovde
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | | | | | - Michael T. Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| |
Collapse
|
14
|
Vogler BW, Brannum J, Chung JW, Seger M, Posewitz MC. Characterization of the Nannochloropsis gaditana storage carbohydrate: A 1,3-beta glucan with limited 1,6-branching. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
15
|
Weissman JC, Likhogrud M, Thomas DC, Fang W, Karns DA, Chung JW, Nielsen R, Posewitz MC. High-light selection produces a fast-growing Picochlorum celeri. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.09.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
16
|
Dahlin LR, Van Wychen S, Gerken HG, McGowen J, Pienkos PT, Posewitz MC, Guarnieri MT. Down-Selection and Outdoor Evaluation of Novel, Halotolerant Algal Strains for Winter Cultivation. Front Plant Sci 2018; 9:1513. [PMID: 30459782 PMCID: PMC6232915 DOI: 10.3389/fpls.2018.01513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/26/2018] [Indexed: 06/09/2023]
Abstract
Algae offer promising feedstocks for the production of renewable fuel and chemical intermediates. However, poor outdoor winter cultivation capacity currently limits deployment potential. In this study, 300 distinct algal strains were screened in saline medium to determine their cultivation suitability during winter conditions in Mesa, Arizona. Three strains, from the genera Micractinium, Chlorella, and Scenedesmus, were chosen following laboratory evaluations and grown outdoors in 1000 L raceway ponds during the winter. Strains were down-selected based on doubling time, lipid and carbohydrate amount, final biomass accumulation capacity, cell size and phylogenetic diversity. Algal biomass productivity and compositional analysis for lipids and carbohydrates show successful outdoor deployment and cultivation under winter conditions for these strains. Outdoor harvest-yield biomass productivities ranged from 2.9 to 4.0 g/m2/day over an 18 days winter cultivation trial, with maximum productivities ranging from 4.0 to 6.5 g/m2/day, the highest productivities reported to date for algal winter strains grown in saline media in open raceway ponds. Peak fatty acid levels ranged from 9 to 26% percent of biomass, and peak carbohydrate levels ranged from 13 to 34% depending on the strain. Changes in the lipid and carbohydrate profile throughout outdoor growth are reported. This study demonstrates that algal strain screening under simulated outdoor environmental conditions in the laboratory enables identification of strains with robust biomass productivity and biofuel precursor composition. The strains isolated here represent promising winter deployment candidates for seasonal algal biomass production when using crop rotation strategies.
Collapse
Affiliation(s)
- Lukas R. Dahlin
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Stefanie Van Wychen
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
| | - Henri G. Gerken
- Arizona Center for Algae Technology and Innovation, Arizona State University, Mesa, AZ, United States
| | - John McGowen
- Arizona Center for Algae Technology and Innovation, Arizona State University, Mesa, AZ, United States
| | - Philip T. Pienkos
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
| | - Matthew C. Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO, United States
| | - Michael T. Guarnieri
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
| |
Collapse
|
17
|
Noone S, Ratcliff K, Davis R, Subramanian V, Meuser J, Posewitz MC, King PW, Ghirardi ML. Expression of a clostridial [FeFe]-hydrogenase in Chlamydomonas reinhardtii prolongs photo-production of hydrogen from water splitting. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.12.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
18
|
Liberatore MW, Peterson BN, Nottoli T, McCulloch JM, Jinkerson RE, Boyle NR, Posewitz MC. Effectiveness of cationically modified cellulose polymers for dewatering algae. SEP SCI TECHNOL 2016. [DOI: 10.1080/01496395.2015.1121278] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
19
|
Gu H, Jinkerson RE, Davies FK, Sisson LA, Schneider PE, Posewitz MC. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros Ketoacyl-ACP Synthase. Front Plant Sci 2016; 7:690. [PMID: 27303412 PMCID: PMC4880568 DOI: 10.3389/fpls.2016.00690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/05/2016] [Indexed: 05/12/2023]
Abstract
The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to fivefold. The level of increase is dependent on promoter strength and culturing conditions.
Collapse
Affiliation(s)
- Huiya Gu
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Robert E. Jinkerson
- Department of Plant Biology, Carnegie Institution for Science, StanfordCA, USA
| | - Fiona K. Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Lyle A. Sisson
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Philip E. Schneider
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
- *Correspondence: Matthew C. Posewitz,
| |
Collapse
|
20
|
Morrissey KL, Keirn MI, Inaba Y, Denham AJ, Henry GJ, Vogler BW, Posewitz MC, Stoykovich MP. Recyclable polyampholyte flocculants for the cost-effective dewatering of microalgae and cyanobacteria. ALGAL RES 2015. [DOI: 10.1016/j.algal.2015.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
21
|
Artz JH, White SN, Zadvornyy OA, Fugate CJ, Hicks D, Gauss GH, Posewitz MC, Boyd ES, Peters JW. Biochemical and Structural Properties of a Thermostable Mercuric Ion Reductase from Metallosphaera sedula. Front Bioeng Biotechnol 2015. [PMID: 26217660 PMCID: PMC4500099 DOI: 10.3389/fbioe.2015.00097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Mercuric ion reductase (MerA), a mercury detoxification enzyme, has been tuned by evolution to have high specificity for mercuric ions (Hg2+) and to catalyze their reduction to a more volatile, less toxic elemental form. Here, we present a biochemical and structural characterization of MerA from the thermophilic crenarchaeon Metallosphaera sedula. MerA from M. sedula is a thermostable enzyme, and remains active after extended incubation at 97°C. At 37°C, the NADPH oxidation-linked Hg2+ reduction specific activity was found to be 1.9 μmol/min⋅mg, increasing to 3.1 μmol/min⋅mg at 70°C. M. sedula MerA crystals were obtained and the structure was solved to 1.6 Å, representing the first solved crystal structure of a thermophilic MerA. Comparison of both the crystal structure and amino acid sequence of MerA from M. sedula to mesophillic counterparts provides new insights into the structural determinants that underpin the thermal stability of the enzyme.
Collapse
Affiliation(s)
- Jacob H Artz
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - Spencer N White
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - Oleg A Zadvornyy
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - Corey J Fugate
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - Danny Hicks
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - George H Gauss
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, CO , USA
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University , Bozeman, MT , USA ; Thermal Biology Institute, Montana State University , Bozeman, MT , USA
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| |
Collapse
|
22
|
Zadvornyy OA, Boyd ES, Posewitz MC, Zorin NA, Peters JW. Biochemical and Structural Characterization of Enolase from Chloroflexus aurantiacus: Evidence for a Thermophilic Origin. Front Bioeng Biotechnol 2015; 3:74. [PMID: 26082925 PMCID: PMC4450660 DOI: 10.3389/fbioe.2015.00074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/08/2015] [Indexed: 11/13/2022] Open
Abstract
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate during both glycolysis and gluconeogenesis, and is required by all three domains of life. Here, we report the purification and biochemical and structural characterization of enolase from Chloroflexus aurantiacus, a thermophilic anoxygenic phototroph affiliated with the green non-sulfur bacteria. The protein was purified as a homodimer with a subunit molecular weight of 46 kDa. The temperature optimum for enolase catalysis was 80°C, close to the measured thermal stability of the protein which was determined to be 75°C, while the pH optimum for enzyme activity was 6.5. The specific activities of purified enolase determined at 25 and 80°C were 147 and 300 U mg(-1) of protein, respectively. K m values for the 2-phosphoglycerate/phosphoenolpyruvate reaction determined at 25 and 80°C were 0.16 and 0.03 mM, respectively. The K m values for Mg(2+) binding at these temperatures were 2.5 and 1.9 mM, respectively. When compared to enolase from mesophiles, the biochemical and structural properties of enolase from C. aurantiacus are consistent with this being thermally adapted. These data are consistent with the results of our phylogenetic analysis of enolase, which reveal that enolase has a thermophilic origin.
Collapse
Affiliation(s)
- Oleg A Zadvornyy
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA ; Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino , Russia
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University , Bozeman, MT , USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, CO , USA
| | - Nikolay A Zorin
- Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino , Russia
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
| |
Collapse
|
23
|
Gu H, Nagle N, Pienkos PT, Posewitz MC. Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus. Bioresour Technol 2015; 184:153-160. [PMID: 25539998 DOI: 10.1016/j.biortech.2014.11.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 05/18/2023]
Abstract
In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth.
Collapse
Affiliation(s)
- Huiya Gu
- Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401, USA
| | - Nick Nagle
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Philip T Pienkos
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401, USA.
| |
Collapse
|
24
|
Yang W, Catalanotti C, Wittkopp TM, Posewitz MC, Grossman AR. Algae after dark: mechanisms to cope with anoxic/hypoxic conditions. Plant J 2015; 82:481-503. [PMID: 25752440 DOI: 10.1111/tpj.12823] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 06/04/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular, soil-dwelling (and aquatic) green alga that has significant metabolic flexibility for balancing redox equivalents and generating ATP when it experiences hypoxic/anoxic conditions. The diversity of pathways available to ferment sugars is often revealed in mutants in which the activities of specific branches of fermentative metabolism have been eliminated; compensatory pathways that have little activity in parental strains under standard laboratory fermentative conditions are often activated. The ways in which these pathways are regulated and integrated have not been extensively explored. In this review, we primarily discuss the intricacies of dark anoxic metabolism in Chlamydomonas, but also discuss aspects of dark oxic metabolism, the utilization of acetate, and the relatively uncharacterized but critical interactions that link chloroplastic and mitochondrial metabolic networks.
Collapse
Affiliation(s)
- Wenqiang Yang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Claudia Catalanotti
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| |
Collapse
|
25
|
Work VH, Melnicki MR, Hill EA, Davies FK, Kucek LA, Beliaev AS, Posewitz MC. Lauric Acid Production in a Glycogen-Less Strain of Synechococcus sp. PCC 7002. Front Bioeng Biotechnol 2015; 3:48. [PMID: 25964950 PMCID: PMC4408914 DOI: 10.3389/fbioe.2015.00048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 03/25/2015] [Indexed: 12/04/2022] Open
Abstract
The cyanobacterium Synechococcus sp. Pasteur culture collection 7002 was genetically engineered to synthesize biofuel-compatible medium-chain fatty acids (FAs) during photoautotrophic growth. Expression of a heterologous lauroyl-acyl carrier protein (C12:0-ACP) thioesterase with concurrent deletion of the endogenous putative acyl-ACP synthetase led to secretion of transesterifiable C12:0 FA in CO2-supplemented batch cultures. When grown at steady state over a range of light intensities in a light-emitting diode turbidostat photobioreactor, the C12-secreting mutant exhibited a modest reduction in growth rate and increased O2 evolution relative to the wild-type (WT). Inhibition of (i) glycogen synthesis by deletion of the glgC-encoded ADP-glucose pyrophosphorylase (AGPase) and (ii) protein synthesis by nitrogen deprivation were investigated as potential mechanisms for metabolite redistribution to increase FA synthesis. Deletion of AGPase led to a 10-fold decrease in reducing carbohydrates and secretion of organic acids during nitrogen deprivation consistent with an energy spilling phenotype. When the carbohydrate-deficient background (ΔglgC) was modified for C12 secretion, no increase in C12 was achieved during nutrient replete growth, and no C12 was recovered from any strain upon nitrogen deprivation under the conditions used. At steady state, the growth rate of the ΔglgC strain saturated at a lower light intensity than the WT, but O2 evolution was not compromised and became increasingly decoupled from growth rate with rising irradiance. Photophysiological properties of the ΔglgC strain suggest energy dissipation from photosystem II and reconfiguration of electron flow at the level of the plastoquinone pool.
Collapse
Affiliation(s)
- Victoria H. Work
- Civil and Environmental Engineering Division, Colorado School of Mines, Golden, CO, USA
| | - Matthew R. Melnicki
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Eric A. Hill
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Fiona K. Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
| | - Leo A. Kucek
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | | | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
| |
Collapse
|
26
|
Davies FK, Jinkerson RE, Posewitz MC. Toward a photosynthetic microbial platform for terpenoid engineering. Photosynth Res 2015; 123:265-84. [PMID: 24510550 DOI: 10.1007/s11120-014-9979-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/23/2014] [Indexed: 05/20/2023]
Abstract
Plant terpenoids are among the most diverse group of naturally-occurring organic compounds known, and several are used in contemporary consumer products. Terpene synthase enzymes catalyze complex rearrangements of carbon skeleton precursors to yield thousands of unique chemical structures that range in size from the simplest five carbon isoprene unit to the long polymers of rubber. Such chemical diversity has established plant terpenoids as valuable commodity chemicals with applications in the pharmaceutical, neutraceutical, cosmetic, and food industries. More recently, terpenoids have received attention as a renewable alternative to petroleum-derived fuels and as the building blocks of synthetic biopolymers. However, the current plant- and petrochemical-based supplies of commodity terpenoids have major limitations. Photosynthetic microorganisms provide an opportunity to generate terpenoids in a renewable manner, employing a single consolidated host organism that is able to use solar energy, H2O and CO2 as the primary inputs for terpenoid biosynthesis. Advances in synthetic biology have seen important breakthroughs in microbial terpenoid engineering, traditionally via fermentative pathways in yeast and Escherichia coli. This review draws on the knowledge obtained from heterotrophic microbial engineering to propose strategies for the development of microbial photosynthetic platforms for industrial terpenoid production. The importance of utilizing the wealth of genetic information provided by nature to unravel the regulatory mechanisms of terpenoid biosynthesis is highlighted.
Collapse
Affiliation(s)
- Fiona K Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, 80401, USA,
| | | | | |
Collapse
|
27
|
Krishnan A, Kumaraswamy GK, Vinyard DJ, Gu H, Ananyev G, Posewitz MC, Dismukes GC. Metabolic and photosynthetic consequences of blocking starch biosynthesis in the green alga Chlamydomonas reinhardtii sta6 mutant. Plant J 2015; 81:947-60. [PMID: 25645872 DOI: 10.1111/tpj.12783] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 05/20/2023]
Abstract
Upon nutrient deprivation, microalgae partition photosynthate into starch and lipids at the expense of protein synthesis and growth. We investigated the role of starch biosynthesis with respect to photosynthetic growth and carbon partitioning in the Chlamydomonas reinhardtii starchless mutant, sta6, which lacks ADP-glucose pyrophosphorylase. This mutant is unable to convert glucose-1-phosphate to ADP-glucose, the precursor of starch biosynthesis. During nutrient-replete culturing, sta6 does not re-direct metabolism to make more proteins or lipids, and accumulates 20% less biomass. The underlying molecular basis for the decreased biomass phenotype was identified using LC-MS metabolomics studies and flux methods. Above a threshold light intensity, photosynthetic electron transport rates (water → CO2) decrease in sta6 due to attenuated rates of NADPH re-oxidation, without affecting photosystems I or II (no change in isolated photosynthetic electron transport). We observed large accumulations of carbon metabolites that are precursors for the biosynthesis of lipids, amino acids and sugars/starch, indicating system-wide consequences of slower NADPH re-oxidation. Attenuated carbon fixation resulted in imbalances in both redox and adenylate energy. The pool sizes of both pyridine and adenylate nucleotides in sta6 increased substantially to compensate for the slower rate of turnover. Mitochondrial respiration partially relieved the reductant stress; however, prolonged high-light exposure caused accelerated photoinhibition. Thus, starch biosynthesis in Chlamydomonas plays a critical role as a principal carbon sink influencing cellular energy balance however, disrupting starch biosynthesis does not redirect resources to other bioproducts (lipids or proteins) during nutrient-replete culturing, resulting in cells that are susceptible to photochemical damage caused by redox stress.
Collapse
Affiliation(s)
- Anagha Krishnan
- Waksman Institute of Microbiology, Rutgers: The State University of New Jersey, Piscataway, NJ, 08854, USA
| | | | | | | | | | | | | |
Collapse
|
28
|
Boyd ES, Hamilton TL, Swanson KD, Howells AE, Baxter BK, Meuser JE, Posewitz MC, Peters JW. [FeFe]-hydrogenase abundance and diversity along a vertical redox gradient in Great Salt Lake, USA. Int J Mol Sci 2014; 15:21947-66. [PMID: 25464382 PMCID: PMC4284687 DOI: 10.3390/ijms151221947] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 11/29/2022] Open
Abstract
The use of [FeFe]-hydrogenase enzymes for the biotechnological production of H2 or other reduced products has been limited by their sensitivity to oxygen (O2). Here, we apply a PCR-directed approach to determine the distribution, abundance, and diversity of hydA gene fragments along co-varying salinity and O2 gradients in a vertical water column of Great Salt Lake (GSL), UT. The distribution of hydA was constrained to water column transects that had high salt and relatively low O2 concentrations. Recovered HydA deduced amino acid sequences were enriched in hydrophilic amino acids relative to HydA from less saline environments. In addition, they harbored interesting variations in the amino acid environment of the complex H-cluster metalloenzyme active site and putative gas transfer channels that may be important for both H2 transfer and O2 susceptibility. A phylogenetic framework was created to infer the accessory cluster composition and quaternary structure of recovered HydA protein sequences based on phylogenetic relationships and the gene contexts of known complete HydA sequences. Numerous recovered HydA are predicted to harbor multiple N- and C-terminal accessory iron-sulfur cluster binding domains and are likely to exist as multisubunit complexes. This study indicates an important role for [FeFe]-hydrogenases in the functioning of the GSL ecosystem and provides new target genes and variants for use in identifying O2 tolerant enzymes for biotechnological applications.
Collapse
Affiliation(s)
- Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.
| | - Trinity L Hamilton
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Kevin D Swanson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Alta E Howells
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| | - Bonnie K Baxter
- Department of Biology and the Great Salt Lake Institute, Westminster College, Salt Lake City, UT 84105, USA.
| | - Jonathan E Meuser
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA.
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA.
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
| |
Collapse
|
29
|
Yang W, Catalanotti C, D'Adamo S, Wittkopp TM, Ingram-Smith CJ, Mackinder L, Miller TE, Heuberger AL, Peers G, Smith KS, Jonikas MC, Grossman AR, Posewitz MC. Alternative acetate production pathways in Chlamydomonas reinhardtii during dark anoxia and the dominant role of chloroplasts in fermentative acetate production. Plant Cell 2014; 26:4499-518. [PMID: 25381350 PMCID: PMC4277214 DOI: 10.1105/tpc.114.129965] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 07/15/2014] [Accepted: 10/15/2014] [Indexed: 05/18/2023]
Abstract
Chlamydomonas reinhardtii insertion mutants disrupted for genes encoding acetate kinases (EC 2.7.2.1) (ACK1 and ACK2) and a phosphate acetyltransferase (EC 2.3.1.8) (PAT2, but not PAT1) were isolated to characterize fermentative acetate production. ACK1 and PAT2 were localized to chloroplasts, while ACK2 and PAT1 were shown to be in mitochondria. Characterization of the mutants showed that PAT2 and ACK1 activity in chloroplasts plays a dominant role (relative to ACK2 and PAT1 in mitochondria) in producing acetate under dark, anoxic conditions and, surprisingly, also suggested that Chlamydomonas has other pathways that generate acetate in the absence of ACK activity. We identified a number of proteins associated with alternative pathways for acetate production that are encoded on the Chlamydomonas genome. Furthermore, we observed that only modest alterations in the accumulation of fermentative products occurred in the ack1, ack2, and ack1 ack2 mutants, which contrasts with the substantial metabolite alterations described in strains devoid of other key fermentation enzymes.
Collapse
Affiliation(s)
- Wenqiang Yang
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305
| | - Claudia Catalanotti
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305
| | - Sarah D'Adamo
- Colorado School of Mines, Department of Chemistry and Geochemistry, Golden, Colorado 80401
| | - Tyler M Wittkopp
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305 Stanford University, Department of Biology, Stanford, California 94305
| | - Cheryl J Ingram-Smith
- Clemson University, Department of Genetics and Biochemistry, Clemson, South Carolina 29634
| | - Luke Mackinder
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305
| | - Tarryn E Miller
- Colorado School of Mines, Department of Chemistry and Geochemistry, Golden, Colorado 80401
| | - Adam L Heuberger
- Colorado State University, Proteomics and Metabolomics Facility, Fort Collins, Colorado 80523
| | - Graham Peers
- Colorado State University, Department of Biology, Fort Collins, Colorado 80523
| | - Kerry S Smith
- Clemson University, Department of Genetics and Biochemistry, Clemson, South Carolina 29634
| | - Martin C Jonikas
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305
| | - Arthur R Grossman
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305
| | - Matthew C Posewitz
- Colorado School of Mines, Department of Chemistry and Geochemistry, Golden, Colorado 80401
| |
Collapse
|
30
|
Subramanian V, Dubini A, Astling DP, Laurens LML, Old WM, Grossman AR, Posewitz MC, Seibert M. Profiling Chlamydomonas metabolism under dark, anoxic H2-producing conditions using a combined proteomic, transcriptomic, and metabolomic approach. J Proteome Res 2014; 13:5431-51. [PMID: 25333711 DOI: 10.1021/pr500342j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Chlamydomonas reinhardtii is well adapted to survive under different environmental conditions due to the unique flexibility of its metabolism. Here we report metabolic pathways that are active during acclimation to anoxia, but were previously not thoroughly studied under dark, anoxic H2-producing conditions in this model green alga. Proteomic analyses, using 2D-differential in-gel electrophoresis in combination with shotgun mass fingerprinting, revealed increased levels of proteins involved in the glycolytic pathway downstream of 3-phosphoglycerate, the glyoxylate pathway, and steps of the tricarboxylic acid (TCA) reactions. Upregulation of the enzyme, isocitrate lyase (ICL), was observed, which was accompanied by increased intracellular succinate levels, suggesting the functioning of glyoxylate pathway reactions. The ICL-inhibitor study revealed presence of reverse TCA reactions under these conditions. Contributions of the serine-isocitrate lyase pathway, glycine cleavage system, and c1-THF/serine hydroxymethyltransferase pathway in the acclimation to dark anoxia were found. We also observed increased levels of amino acids (AAs) suggesting nitrogen reorganization in the form of de novo AA biosynthesis during anoxia. Overall, novel routes for reductant utilization, in combination with redistribution of carbon and nitrogen, are used by this alga during acclimation to O2 deprivation in the dark.
Collapse
|
31
|
Keeling PJ, Burki F, Wilcox HM, Allam B, Allen EE, Amaral-Zettler LA, Armbrust EV, Archibald JM, Bharti AK, Bell CJ, Beszteri B, Bidle KD, Cameron CT, Campbell L, Caron DA, Cattolico RA, Collier JL, Coyne K, Davy SK, Deschamps P, Dyhrman ST, Edvardsen B, Gates RD, Gobler CJ, Greenwood SJ, Guida SM, Jacobi JL, Jakobsen KS, James ER, Jenkins B, John U, Johnson MD, Juhl AR, Kamp A, Katz LA, Kiene R, Kudryavtsev A, Leander BS, Lin S, Lovejoy C, Lynn D, Marchetti A, McManus G, Nedelcu AM, Menden-Deuer S, Miceli C, Mock T, Montresor M, Moran MA, Murray S, Nadathur G, Nagai S, Ngam PB, Palenik B, Pawlowski J, Petroni G, Piganeau G, Posewitz MC, Rengefors K, Romano G, Rumpho ME, Rynearson T, Schilling KB, Schroeder DC, Simpson AGB, Slamovits CH, Smith DR, Smith GJ, Smith SR, Sosik HM, Stief P, Theriot E, Twary SN, Umale PE, Vaulot D, Wawrik B, Wheeler GL, Wilson WH, Xu Y, Zingone A, Worden AZ. The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): illuminating the functional diversity of eukaryotic life in the oceans through transcriptome sequencing. PLoS Biol 2014; 12:e1001889. [PMID: 24959919 PMCID: PMC4068987 DOI: 10.1371/journal.pbio.1001889] [Citation(s) in RCA: 613] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Current sampling of genomic sequence data from eukaryotes is relatively poor, biased, and inadequate to address important questions about their biology, evolution, and ecology; this Community Page describes a resource of 700 transcriptomes from marine microbial eukaryotes to help understand their role in the world's oceans.
Collapse
Affiliation(s)
- Patrick J. Keeling
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
- Canadian Institute for Advanced Research, Integrated Microbial Biodiversity program, Canada
- * E-mail: (PJK); (AZW)
| | - Fabien Burki
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Heather M. Wilcox
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
| | - Bassem Allam
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Eric E. Allen
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Linda A. Amaral-Zettler
- The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
- Department of Geological Sciences, Brown University, Providence, Rhode Island, United States of America
| | - E. Virginia Armbrust
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
| | - John M. Archibald
- Canadian Institute for Advanced Research, Integrated Microbial Biodiversity program, Canada
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Arvind K. Bharti
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Callum J. Bell
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Bank Beszteri
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | - Kay D. Bidle
- Institute of Marine and Coastal Science, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Connor T. Cameron
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Lisa Campbell
- Department of Oceanography, Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - David A. Caron
- Department of Biology, University of Southern California, Los Angeles, California, United States of America
| | - Rose Ann Cattolico
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Jackie L. Collier
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Kathryn Coyne
- University of Delaware, School of Marine Science and Policy, College of Earth, Ocean, and Environment, Lewes, Delaware, United States of America
| | - Simon K. Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Phillipe Deschamps
- Unité d'Ecologie, Systematique et Evolution, CNRS UMR8079, Université Paris-Sud, Orsay, France
| | - Sonya T. Dyhrman
- Department of Earth and Environmental Sciences and the Lamont-Doherty Earth Observatory, Columbia University, New York, New York, United States of America
| | | | - Ruth D. Gates
- Hawaii Institute of Marine Biology, University of Hawaii, Hawaii, United States of America
| | - Christopher J. Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Spencer J. Greenwood
- Department of Biomedical Sciences and AVC Lobster Science Centre, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Stephanie M. Guida
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Jennifer L. Jacobi
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | | | - Erick R. James
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bethany Jenkins
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, United States of America
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, United States of America
| | - Uwe John
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | - Matthew D. Johnson
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - Andrew R. Juhl
- Department of Earth and Environmental Sciences and the Lamont-Doherty Earth Observatory, Columbia University, New York, New York, United States of America
| | - Anja Kamp
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Jacobs University Bremen, Molecular Life Science Research Center, Bremen, Germany
| | - Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Ronald Kiene
- University of South Alabama, Dauphin Island Sea Lab, Mobile, Alabama, United States of America
| | - Alexander Kudryavtsev
- Department of Invertebrate Zoology, Saint-Petersburg State University, Saint-Petersburg, Russia
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Brian S. Leander
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut, United States of America
| | - Connie Lovejoy
- Département de Biologie, Université Laval, Québec, Canada
| | - Denis Lynn
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Adrian Marchetti
- Department of Marine Sciences, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - George McManus
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut, United States of America
| | - Aurora M. Nedelcu
- University of New Brunswick, Department of Biology, Fredericton, New Brusnswick, Canada
| | - Susanne Menden-Deuer
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, United States of America
| | - Cristina Miceli
- School of Biosciences and Biotechnology, University of Camerino, Camerino, Italy
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | | | - Mary Ann Moran
- Department of Marine Sciences, University of Georgia, Athens, Georgia, United States of America
| | - Shauna Murray
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology, Sydney, Australia
| | - Govind Nadathur
- Department of Marine Sciences, University of Puerto Rico, Mayaguez, Puerto Rico, United States of America
| | - Satoshi Nagai
- National Research Institute of Fisheries Science, Kanagawa, Japan
| | - Peter B. Ngam
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Brian Palenik
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Jan Pawlowski
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | | | - Gwenael Piganeau
- CNRS, UMR 7232, BIOM, Observatoire Océanologique, Banyuls-sur-Mer, France
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7232, BIOM, Banyuls-sur-Mer, France
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, United States of America
| | | | | | - Mary E. Rumpho
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Tatiana Rynearson
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, United States of America
| | - Kelly B. Schilling
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Declan C. Schroeder
- The Marine Biological Association of the United Kingdom, Plymouth, United Kingdom
| | - Alastair G. B. Simpson
- Canadian Institute for Advanced Research, Integrated Microbial Biodiversity program, Canada
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Claudio H. Slamovits
- Canadian Institute for Advanced Research, Integrated Microbial Biodiversity program, Canada
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - G. Jason Smith
- Moss Landing Marine Laboratories, Moss Landing, California, United States of America
| | - Sarah R. Smith
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Heidi M. Sosik
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - Peter Stief
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Edward Theriot
- Section of Integrative Biology, University of Texas, Austin, Texas, United States of America
| | - Scott N. Twary
- Los Alamos National Laboratory, Biosciences, Los Alamos, New Mexico, United States of America
| | - Pooja E. Umale
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Daniel Vaulot
- UMR714, CNRS and UPMC (Paris-06), Station Biologique, Roscoff, France
| | - Boris Wawrik
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Glen L. Wheeler
- The Marine Biological Association of the United Kingdom, Plymouth, United Kingdom
- Plymouth Marine Laboratory, Plymouth, United Kingdom
| | - William H. Wilson
- NCMA, Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, United States of America
| | - Yan Xu
- Princeton University, Princeton, New Jersey, United States of America
| | | | - Alexandra Z. Worden
- Canadian Institute for Advanced Research, Integrated Microbial Biodiversity program, Canada
- Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America
- * E-mail: (PJK); (AZW)
| |
Collapse
|
32
|
Davies FK, Work VH, Beliaev AS, Posewitz MC. Engineering Limonene and Bisabolene Production in Wild Type and a Glycogen-Deficient Mutant of Synechococcus sp. PCC 7002. Front Bioeng Biotechnol 2014; 2:21. [PMID: 25152894 PMCID: PMC4126464 DOI: 10.3389/fbioe.2014.00021] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/04/2014] [Indexed: 02/05/2023] Open
Abstract
The plant terpenoids limonene (C10H16) and α-bisabolene (C15H24) are hydrocarbon precursors to a range of industrially relevant chemicals. High-titer microbial synthesis of limonene and α-bisabolene could pave the way for advances in in vivo engineering of tailor-made hydrocarbons, and production at commercial scale. We have engineered the fast-growing unicellular euryhaline cyanobacterium Synechococcus sp. PCC 7002 to produce yields of 4 mg L−1 limonene and 0.6 mg L−1 α-bisabolene through heterologous expression of the Mentha spicatal-limonene synthase or the Abies grandis (E)-α-bisabolene synthase genes, respectively. Titers were significantly higher when a dodecane overlay was applied during culturing, suggesting either that dodecane traps large quantities of volatile limonene or α-bisabolene that would otherwise be lost to evaporation, and/or that continuous product removal in dodecane alleviates product feedback inhibition to promote higher rates of synthesis. We also investigate limonene and bisabolene production in the ΔglgC genetic background, where carbon partitioning is redirected at the expense of glycogen biosynthesis. The Synechococcus sp. PCC 7002 ΔglgC mutant excreted a suite of overflow metabolites (α-ketoisocaproate, pyruvate, α-ketoglutarate, succinate, and acetate) during nitrogen-deprivation, and also at the onset of stationary growth in nutrient-replete media. None of the excreted metabolites, however, appeared to be effectively utilized for terpenoid metabolism. Interestingly, we observed a 1.6- to 2.5-fold increase in the extracellular concentration of most excreted organic acids when the ΔglgC mutant was conferred with the ability to produce limonene. Overall, Synechococcus sp. PCC 7002 provides a highly promising platform for terpenoid biosynthetic and metabolic engineering efforts.
Collapse
Affiliation(s)
- Fiona K Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, CO , USA
| | - Victoria H Work
- Civil and Environmental Engineering Division, Colorado School of Mines , Golden, CO , USA
| | - Alexander S Beliaev
- Biological Sciences Division, Pacific Northwest National Laboratory , Richland, WA , USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, CO , USA
| |
Collapse
|
33
|
D'Adamo S, Jinkerson RE, Boyd ES, Brown SL, Baxter BK, Peters JW, Posewitz MC. Evolutionary and biotechnological implications of robust hydrogenase activity in halophilic strains of Tetraselmis. PLoS One 2014; 9:e85812. [PMID: 24465722 PMCID: PMC3897525 DOI: 10.1371/journal.pone.0085812] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 12/02/2013] [Indexed: 11/19/2022] Open
Abstract
Although significant advances in H2 photoproduction have recently been realized in fresh water algae (e.g. Chlamydomonas reinhardtii), relatively few studies have focused on H2 production and hydrogenase adaptations in marine or halophilic algae. Salt water organisms likely offer several advantages for biotechnological H2 production due to the global abundance of salt water, decreased H2 and O2 solubility in saline and hypersaline systems, and the ability of extracellular NaCl levels to influence metabolism. We screened unialgal isolates obtained from hypersaline ecosystems in the southwest United States and identified two distinct halophilic strains of the genus Tetraselmis (GSL1 and QNM1) that exhibit both robust fermentative and photo H2-production activities. The influence of salinity (3.5%, 5.5% and 7.0% w/v NaCl) on H2 production was examined during anoxic acclimation, with the greatest in vivo H2-production rates observed at 7.0% NaCl. These Tetraselmis strains maintain robust hydrogenase activity even after 24 h of anoxic acclimation and show increased hydrogenase activity relative to C. reinhardtii after extended anoxia. Transcriptional analysis of Tetraselmis GSL1 enabled sequencing of the cDNA encoding the FeFe-hydrogenase structural enzyme (HYDA) and its maturation proteins (HYDE, HYDEF and HYDG). In contrast to freshwater Chlorophyceae, the halophilic Tetraselmis GSL1 strain likely encodes a single HYDA and two copies of HYDE, one of which is fused to HYDF. Phylogenetic analyses of HYDA and concatenated HYDA, HYDE, HYDF and HYDG in Tetraselmis GSL1 fill existing knowledge gaps in the evolution of algal hydrogenases and indicate that the algal hydrogenases sequenced to date are derived from a common ancestor. This is consistent with recent hypotheses that suggest fermentative metabolism in the majority of eukaryotes is derived from a common base set of enzymes that emerged early in eukaryotic evolution with subsequent losses in some organisms.
Collapse
Affiliation(s)
- Sarah D'Adamo
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, United States of America
| | - Robert E. Jinkerson
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, United States of America
| | - Eric S. Boyd
- Department of Microbiology and the Thermal Biology Institute, Montana State University, Bozeman, Montana, United States of America
| | - Susan L. Brown
- Center for Marine Microbial Ecology and Diversity, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Bonnie K. Baxter
- Department of Biology and the Great Salt Lake Institute, Westminster College, Salt Lake City, Utah, United States of America
| | - John W. Peters
- Department of Microbiology and the Thermal Biology Institute, Montana State University, Bozeman, Montana, United States of America
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado, United States of America
| |
Collapse
|
34
|
Therien JB, Zadvornyy OA, Posewitz MC, Bryant DA, Peters JW. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002. Biotechnol Biofuels 2014; 7:154. [PMID: 25364380 PMCID: PMC4216383 DOI: 10.1186/s13068-014-0154-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/02/2014] [Indexed: 05/05/2023]
Abstract
BACKGROUND The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. Here we demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC 7002. RESULTS Optimal growth conditions for co-cultivation of C. reinhardtii with wild-type and mutant strains of Synechococcus sp. 7002 were established. In co-culture, acetate produced by a glycogen synthase knockout mutant of Synechococcus sp. PCC 7002 was able to support the growth of a lipid-accumulating mutant strain of C. reinhardtii defective in starch production. Encapsulation of Synechococcus sp. PCC 7002 using an alginate matrix was successfully employed in co-cultures to limit growth and maintain the stability. CONCLUSIONS The ability of immobilized strains of the cyanobacterium Synechococcus sp. PCC 7002 to produce acetate at a level adequate to support the growth of lipid-accumulating strains of C. reinhartdii offers a potentially practical, photosynthetic alternative to providing exogenous acetate into growth media.
Collapse
Affiliation(s)
- Jesse B Therien
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
| | - Oleg A Zadvornyy
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
| | - Matthew C Posewitz
- />Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401 USA
| | - Donald A Bryant
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
- />Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | - John W Peters
- />Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA
| |
Collapse
|
35
|
Radakovits R, Jinkerson RE, Fuerstenberg SI, Tae H, Settlage RE, Boore JL, Posewitz MC. Erratum: Corrigendum: Draft genome sequence and genetic transformation of the oleaginous alga Nannochloropsis gaditana. Nat Commun 2013. [PMCID: PMC3868315 DOI: 10.1038/ncomms3356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
36
|
Meuser JE, Baxter BK, Spear JR, Peters JW, Posewitz MC, Boyd ES. Contrasting patterns of community assembly in the stratified water column of Great Salt Lake, Utah. Microb Ecol 2013; 66:268-80. [PMID: 23354179 DOI: 10.1007/s00248-013-0180-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 01/09/2013] [Indexed: 05/26/2023]
Abstract
Phylogenetic examinations of communities sampled along geochemical gradients provide a framework for inferring the relative importance of niche-based ecological interactions (competition, environmental filtering) and neutral-based evolutionary interactions in structuring biodiversity. Great Salt Lake (GSL) in Utah exhibits strong spatial gradients due to both seasonal variation in freshwater input into the watershed and restricted fluid flow within North America's largest saline terminal lake ecosystem. Here, we examine the phylogenetic structure and composition of archaeal, bacterial, and eukaryal small subunit (SSU) rRNA genes sampled along a stratified water column (DWR3) in the south arm of GSL in order to infer the underlying mechanism of community assembly. Communities sampled from the DWR3 epilimnion were phylogenetically clustered (i.e., coexistence of close relatives due to environmental filtering) whereas those sampled from the DWR3 hypolimnion were phylogenetically overdispersed (i.e., coexistence of distant relatives due to competitive interactions), with minimal evidence for a role for neutral processes in structuring any assemblage. The shift from phylogenetically clustered to overdispersed assemblages was associated with an increase in salinity and a decrease in dissolved O2 (DO) concentration. Likewise, the phylogenetic diversity and phylogenetic similarity of assemblages was strongly associated with salinity or DO gradients. Thus, salinity and/or DO appeared to influence the mechanism of community assembly as well as the phylogenetic diversity and composition of communities. It is proposed that the observed patterns in the phylogenetic composition and structure of DWR3 assemblages are attributable to the meromictic nature of GSL, which prevents significant mixing between the epilimnion and the hypolimnion. This leads to strong physicochemical gradients at the halocline, which are capable of supporting a greater diversity. However, concomitant shifts in nutrient availability (e.g., DO) at and below the halocline drive competitive interactions leading to hypolimnion assemblages with minimal niche overlap.
Collapse
Affiliation(s)
- Jonathan E Meuser
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | | | | | | | | | | |
Collapse
|
37
|
Catalanotti C, Yang W, Posewitz MC, Grossman AR. Fermentation metabolism and its evolution in algae. Front Plant Sci 2013; 4:150. [PMID: 23734158 PMCID: PMC3660698 DOI: 10.3389/fpls.2013.00150] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/02/2013] [Indexed: 05/20/2023]
Abstract
Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume.
Collapse
Affiliation(s)
- Claudia Catalanotti
- Department of Plant Biology, Carnegie Institution for ScienceStanford, CA, USA
| | - Wenqiang Yang
- Department of Plant Biology, Carnegie Institution for ScienceStanford, CA, USA
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of MinesGolden, CO, USA
| | - Arthur R. Grossman
- Department of Plant Biology, Carnegie Institution for ScienceStanford, CA, USA
| |
Collapse
|
38
|
Elliott LG, Feehan C, Laurens LM, Pienkos PT, Darzins A, Posewitz MC. Establishment of a bioenergy-focused microalgal culture collection. ALGAL RES 2012. [DOI: 10.1016/j.algal.2012.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
39
|
Abstract
Nannochloropsis species have emerged as leading phototrophic microorganisms for the production of biofuels. Several isolates produce large quantities of triacylglycerols, grow rapidly, and can be cultivated at industrial scales. Recently, the mitochondrial, plastid and nuclear genomes of Nannochloropsis gaditana were sequenced. Genomic interrogation revealed several key features that likely facilitate the oleaginous phenotype observed in Nannochloropsis, including an over-representation of genes involved in lipid biosynthesis. Here we present additional analyses on gene orientation, vitamin B12 requiring enzymes, the acetyl-CoA metabolic node, and codon usage in N. gaditana. Nuclear genome transformation methods are established with exogenous DNA integration occurring via either random incorporation or by homologous recombination, making Nannochloropsis amenable to both forward and reverse genetic engineering. Completion of a draft genomic sequence, establishment of transformation techniques, and robust outdoor growth properties have positioned Nannochloropsis as a new model alga with significant potential for further development into an integrated photons-to-fuel production platform.
Collapse
Affiliation(s)
- Robert E Jinkerson
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
| | | | | |
Collapse
|
40
|
Murthy UMN, Wecker MSA, Posewitz MC, Gilles-Gonzalez MA, Ghirardi ML. Novel FixL homologues in Chlamydomonas reinhardtii bind heme and O(2). FEBS Lett 2012; 586:4282-8. [PMID: 22801216 DOI: 10.1016/j.febslet.2012.06.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/26/2012] [Accepted: 06/28/2012] [Indexed: 11/17/2022]
Abstract
Genome inspection revealed nine putative heme-binding, FixL-homologous proteins in Chlamydomonas reinhardtii. The heme-binding domains from two of these proteins, FXL1 and FXL5 were cloned, expressed in Escherichia coli, purified and characterized. The recombinant FXL1 and FXL5 domains stained positively for heme, while mutations in the putative ligand-binding histidine FXL1-H200S and FXL5-H200S resulted in loss of heme binding. The FXL1 and FXL5 [Fe(II), bound O(2)] had Soret absorption maxima around 415 nm, and weaker absorptions at longer wavelengths, in concurrence with the literature. Ligand-binding measurements showed that FXL1 and FXL5 bind O(2) with moderate affinity, 135 and 222 μM, respectively. This suggests that Chlamydomonas may use the FXL proteins in O(2)-sensing mechanisms analogous to that reported in nitrogen-fixing bacteria to regulate gene expression.
Collapse
Affiliation(s)
- U M Narayana Murthy
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | | | | | | | | |
Collapse
|
41
|
Magneschi L, Catalanotti C, Subramanian V, Dubini A, Yang W, Mus F, Posewitz MC, Seibert M, Perata P, Grossman AR. A mutant in the ADH1 gene of Chlamydomonas reinhardtii elicits metabolic restructuring during anaerobiosis. Plant Physiol 2012; 158:1293-305. [PMID: 22271746 PMCID: PMC3291268 DOI: 10.1104/pp.111.191569] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/21/2012] [Indexed: 05/20/2023]
Abstract
The green alga Chlamydomonas reinhardtii has numerous genes encoding enzymes that function in fermentative pathways. Among these, the bifunctional alcohol/acetaldehyde dehydrogenase (ADH1), highly homologous to the Escherichia coli AdhE enzyme, is proposed to be a key component of fermentative metabolism. To investigate the physiological role of ADH1 in dark anoxic metabolism, a Chlamydomonas adh1 mutant was generated. We detected no ethanol synthesis in this mutant when it was placed under anoxia; the two other ADH homologs encoded on the Chlamydomonas genome do not appear to participate in ethanol production under our experimental conditions. Pyruvate formate lyase, acetate kinase, and hydrogenase protein levels were similar in wild-type cells and the adh1 mutant, while the mutant had significantly more pyruvate:ferredoxin oxidoreductase. Furthermore, a marked change in metabolite levels (in addition to ethanol) synthesized by the mutant under anoxic conditions was observed; formate levels were reduced, acetate levels were elevated, and the production of CO(2) was significantly reduced, but fermentative H(2) production was unchanged relative to wild-type cells. Of particular interest is the finding that the mutant accumulates high levels of extracellular glycerol, which requires NADH as a substrate for its synthesis. Lactate production is also increased slightly in the mutant relative to the control strain. These findings demonstrate a restructuring of fermentative metabolism in the adh1 mutant in a way that sustains the recycling (oxidation) of NADH and the survival of the mutant (similar to wild-type cell survival) during dark anoxic growth.
Collapse
Affiliation(s)
- Leonardo Magneschi
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Radakovits R, Jinkerson RE, Fuerstenberg SI, Tae H, Settlage RE, Boore JL, Posewitz MC. Draft genome sequence and genetic transformation of the oleaginous alga Nannochloropis gaditana. Nat Commun 2012; 3:686. [PMID: 22353717 PMCID: PMC3293424 DOI: 10.1038/ncomms1688] [Citation(s) in RCA: 395] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/17/2012] [Indexed: 11/09/2022] Open
Abstract
The potential use of algae in biofuels applications is receiving significant attention. However, none of the current algal model species are competitive production strains. Here we present a draft genome sequence and a genetic transformation method for the marine microalga Nannochloropsis gaditana CCMP526. We show that N. gaditana has highly favourable lipid yields, and is a promising production organism. The genome assembly includes nuclear (~29 Mb) and organellar genomes, and contains 9,052 gene models. We define the genes required for glycerolipid biogenesis and detail the differential regulation of genes during nitrogen-limited lipid biosynthesis. Phylogenomic analysis identifies genetic attributes of this organism, including unique stramenopile photosynthesis genes and gene expansions that may explain the distinguishing photoautotrophic phenotypes observed. The availability of a genome sequence and transformation methods will facilitate investigations into N. gaditana lipid biosynthesis and permit genetic engineering strategies to further improve this naturally productive alga.
Collapse
Affiliation(s)
- Randor Radakovits
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401, USA
- These authors contributed equally to this work
| | - Robert E. Jinkerson
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401, USA
- These authors contributed equally to this work
| | | | - Hongseok Tae
- Data Analysis Core, Virginia Bioinformatics Institute, Virginia Tech, 1 Washington Street, Blacksburg, Virginia 24060, USA
| | - Robert E. Settlage
- Data Analysis Core, Virginia Bioinformatics Institute, Virginia Tech, 1 Washington Street, Blacksburg, Virginia 24060, USA
| | - Jeffrey L. Boore
- Genome Project Solutions, 1024 Promenade Street, Hercules, California 94547, USA
- Department of Integrative Biology, University of California, Berkeley, California 94720, USA
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401, USA
| |
Collapse
|
43
|
Catalanotti C, Dubini A, Subramanian V, Yang W, Magneschi L, Mus F, Seibert M, Posewitz MC, Grossman AR. Altered fermentative metabolism in Chlamydomonas reinhardtii mutants lacking pyruvate formate lyase and both pyruvate formate lyase and alcohol dehydrogenase. Plant Cell 2012; 24:692-707. [PMID: 22353371 PMCID: PMC3315241 DOI: 10.1105/tpc.111.093146] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/05/2012] [Accepted: 01/25/2012] [Indexed: 05/20/2023]
Abstract
Chlamydomonas reinhardtii, a unicellular green alga, often experiences hypoxic/anoxic soil conditions that activate fermentation metabolism. We isolated three Chlamydomonas mutants disrupted for the pyruvate formate lyase (PFL1) gene; the encoded PFL1 protein catalyzes a major fermentative pathway in wild-type Chlamydomonas cells. When the pfl1 mutants were subjected to dark fermentative conditions, they displayed an increased flux of pyruvate to lactate, elevated pyruvate decarboxylation, ethanol accumulation, diminished pyruvate oxidation by pyruvate ferredoxin oxidoreductase, and lowered H(2) production. The pfl1-1 mutant also accumulated high intracellular levels of lactate, succinate, alanine, malate, and fumarate. To further probe the system, we generated a double mutant (pfl1-1 adh1) that is unable to synthesize both formate and ethanol. This strain, like the pfl1 mutants, secreted lactate, but it also exhibited a significant increase in the levels of extracellular glycerol, acetate, and intracellular reduced sugars and a decrease in dark, fermentative H(2) production. Whereas wild-type Chlamydomonas fermentation primarily produces formate and ethanol, the double mutant reroutes glycolytic carbon to lactate and glycerol. Although the metabolic adjustments observed in the mutants facilitate NADH reoxidation and sustained glycolysis under dark, anoxic conditions, the observed changes could not have been predicted given our current knowledge of the regulation of fermentation metabolism.
Collapse
Affiliation(s)
- Claudia Catalanotti
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Meuser JE, D'Adamo S, Jinkerson RE, Mus F, Yang W, Ghirardi ML, Seibert M, Grossman AR, Posewitz MC. Genetic disruption of both Chlamydomonas reinhardtii [FeFe]-hydrogenases: Insight into the role of HYDA2 in H₂ production. Biochem Biophys Res Commun 2011; 417:704-9. [PMID: 22177948 DOI: 10.1016/j.bbrc.2011.12.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 12/01/2011] [Indexed: 11/18/2022]
Abstract
Chlamydomonas reinhardtii (Chlamydomonas throughout) encodes two [FeFe]-hydrogenases, designated HYDA1 and HYDA2. While HYDA1 is considered the dominant hydrogenase, the role of HYDA2 is unclear. To study the individual functions of each hydrogenase and provide a platform for future bioengineering, we isolated the Chlamydomonas hydA1-1, hydA2-1 single mutants and the hydA1-1 hydA2-1 double mutant. A reverse genetic screen was used to identify a mutant with an insertion in HYDA2, followed by mutagenesis of the hydA2-1 strain coupled with a H(2) chemosensor phenotypic screen to isolate the hydA1-1 hydA2-1 mutant. Genetic crosses of the hydA1-1 hydA2-1 mutant to wild-type cells allowed us to also isolate the single hydA1-1 mutant. Fermentative, photosynthetic, and in vitro hydrogenase activities were assayed in each of the mutant genotypes. Surprisingly, analyses of the hydA1-1 and hydA2-1 single mutants, as well as the HYDA1 and HYDA2 rescued hydA1-1 hydA2-1 mutant demonstrated that both hydrogenases are able to catalyze H(2) production from either fermentative or photosynthetic pathways. The physiology of both mutant and complemented strains indicate that the contribution of HYDA2 to H(2) photoproduction is approximately 25% that of HYDA1, which corresponds to similarly low levels of in vitro hydrogenase activity measured in the hydA1-1 mutant. Interestingly, enhanced in vitro and fermentative H(2) production activities were observed in the hydA1-1 hydA2-1 strain complemented with HYDA1, while maximal H(2)-photoproduction rates did not exceed those of wild-type cells.
Collapse
Affiliation(s)
- Jonathan E Meuser
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Cendron L, Berto P, D'Adamo S, Vallese F, Govoni C, Posewitz MC, Giacometti GM, Costantini P, Zanotti G. Crystal structure of HydF scaffold protein provides insights into [FeFe]-hydrogenase maturation. J Biol Chem 2011; 286:43944-43950. [PMID: 22057316 DOI: 10.1074/jbc.m111.281956] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
[FeFe]-hydrogenases catalyze the reversible production of H2 in some bacteria and unicellular eukaryotes. These enzymes require ancillary proteins to assemble the unique active site H-cluster, a complex structure composed of a 2Fe center bridged to a [4Fe-4S] cubane. The first crystal structure of a key factor in the maturation process, HydF, has been determined at 3 Å resolution. The protein monomer present in the asymmetric unit of the crystal comprises three domains: a GTP-binding domain, a dimerization domain, and a metal cluster-binding domain, all characterized by similar folding motifs. Two monomers dimerize, giving rise to a stable dimer, held together mainly by the formation of a continuous β-sheet comprising eight β-strands from two monomers. Moreover, in the structure presented, two dimers aggregate to form a supramolecular organization that represents an inactivated form of the HydF maturase. The crystal structure of the latter furnishes several clues about the events necessary for cluster generation/transfer and provides an excellent model to begin elucidating the structure/function of HydF in [FeFe]-hydrogenase maturation.
Collapse
Affiliation(s)
- Laura Cendron
- Department of Biological Chemistry, University of Padua, 35131 Padua, Italy
| | - Paola Berto
- Department of Biology, University of Padua, 35131 Padua, Italy
| | - Sarah D'Adamo
- Department of Biology, University of Padua, 35131 Padua, Italy; Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
| | | | - Chiara Govoni
- Department of Biotechnologies, University of Verona, 37134 Verona, Italy
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
| | | | | | - Giuseppe Zanotti
- Department of Biological Chemistry, University of Padua, 35131 Padua, Italy.
| |
Collapse
|
46
|
Meuser JE, Boyd ES, Ananyev G, Karns D, Radakovits R, Narayana Murthy UM, Ghirardi ML, Dismukes GC, Peters JW, Posewitz MC. Evolutionary significance of an algal gene encoding an [FeFe]-hydrogenase with F-domain homology and hydrogenase activity in Chlorella variabilis NC64A. Planta 2011; 234:829-43. [PMID: 21643991 DOI: 10.1007/s00425-011-1431-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 05/06/2011] [Indexed: 05/20/2023]
Abstract
[FeFe]-hydrogenases (HYDA) link the production of molecular H(2) to anaerobic metabolism in many green algae. Similar to Chlamydomonas reinhardtii, Chlorella variabilis NC64A (Trebouxiophyceae, Chlorophyta) exhibits [FeFe]-hydrogenase (HYDA) activity during anoxia. In contrast to C. reinhardtii and other chlorophycean algae, which contain hydrogenases with only the HYDA active site (H-cluster), C. variabilis NC64A is the only known green alga containing HYDA genes encoding accessory FeS cluster-binding domains (F-cluster). cDNA sequencing confirmed the presence of F-cluster HYDA1 mRNA transcripts, and identified deviations from the in silico splicing models. We show that HYDA activity in C. variabilis NC64A is coupled to anoxic photosynthetic electron transport (PSII linked, as well as PSII-independent) and dark fermentation. We also show that the in vivo H(2)-photoproduction activity observed is as O(2) sensitive as in C. reinhardtii. The two C. variabilis NC64A HYDA sequences are similar to homologs found in more deeply branching bacteria (Thermotogales), diatoms, and heterotrophic flagellates, suggesting that an F-cluster HYDA is the ancestral enzyme in algae. Phylogenetic analysis indicates that the algal HYDA H-cluster domains are monophyletic, suggesting that they share a common origin, and evolved from a single ancestral F-cluster HYDA. Furthermore, phylogenetic reconstruction indicates that the multiple algal HYDA paralogs are the result of gene duplication events that occurred independently within each algal lineage. Collectively, comparative genomic, physiological, and phylogenetic analyses of the C. variabilis NC64A hydrogenase has provided new insights into the molecular evolution and diversity of algal [FeFe]-hydrogenases.
Collapse
Affiliation(s)
- Jonathan E Meuser
- Division of Environmental Science and Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Reinsvold RE, Jinkerson RE, Radakovits R, Posewitz MC, Basu C. The production of the sesquiterpene β-caryophyllene in a transgenic strain of the cyanobacterium Synechocystis. J Plant Physiol 2011; 168:848-52. [PMID: 21185107 DOI: 10.1016/j.jplph.2010.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/23/2010] [Accepted: 11/25/2010] [Indexed: 05/12/2023]
Abstract
The plant secondary metabolite, β-caryophyllene, is a ubiquitous component of many plant resins that has traditionally been used in the cosmetics industry to provide a woody, spicy aroma to cosmetics and perfumes. Clinical studies have shown it to be potentially effective as an antibiotic, anesthetic, and anti-inflammatory agent. Additionally, there is significant interest in engineering phototrophic microorganisms with sesquiterpene synthase genes for the production of biofuels. Currently, the isolation of β-caryophyllene relies on purification methods from oleoresins extracted from large amounts of plant material. An engineered cyanobacterium platform that produces β-caryophyllene may provide a more sustainable and controllable means of production. To this end, the β-caryophyllene synthase gene (QHS1) from Artemisia annua was stably inserted, via double homologous recombination, into the genome of the cyanobacterium Synechocystis sp. strain PCC6803. Gene insertion into Synechocystis was confirmed through PCR assays and sequencing reactions. Transcription and expression of QHS1 were confirmed using RT-PCR, and synthesis of β-caryophyllene was confirmed in the transgenic strain using GC-FID and GC-MS analysis.
Collapse
Affiliation(s)
- Robert E Reinsvold
- School of Biological Sciences, University of Northern Colorado, Ross Hall, Room 2480, Greeley, CO 80639, United States
| | | | | | | | | |
Collapse
|
48
|
Grossman AR, Catalanotti C, Yang W, Dubini A, Magneschi L, Subramanian V, Posewitz MC, Seibert M. Multiple facets of anoxic metabolism and hydrogen production in the unicellular green alga Chlamydomonas reinhardtii. New Phytol 2011; 190:279-88. [PMID: 21563367 DOI: 10.1111/j.1469-8137.2010.03534.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Many microbes in the soil environment experience micro-oxic or anoxic conditions for much of the late afternoon and night, which inhibit or prevent respiratory metabolism. To sustain the production of energy and maintain vital cellular processes during the night, organisms have developed numerous pathways for fermentative metabolism. This review discusses fermentation pathways identified for the soil-dwelling model alga Chlamydomonas reinhardtii, its ability to produce molecular hydrogen under anoxic conditions through the activity of hydrogenases, and the molecular flexibility associated with fermentative metabolism that has only recently been revealed through the analysis of specific mutant strains.
Collapse
Affiliation(s)
- Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Abstract
There are currently intensive global research efforts aimed at increasing and modifying the accumulation of lipids, alcohols, hydrocarbons, polysaccharides, and other energy storage compounds in photosynthetic organisms, yeast, and bacteria through genetic engineering. Many improvements have been realized, including increased lipid and carbohydrate production, improved H(2) yields, and the diversion of central metabolic intermediates into fungible biofuels. Photosynthetic microorganisms are attracting considerable interest within these efforts due to their relatively high photosynthetic conversion efficiencies, diverse metabolic capabilities, superior growth rates, and ability to store or secrete energy-rich hydrocarbons. Relative to cyanobacteria, eukaryotic microalgae possess several unique metabolic attributes of relevance to biofuel production, including the accumulation of significant quantities of triacylglycerol; the synthesis of storage starch (amylopectin and amylose), which is similar to that found in higher plants; and the ability to efficiently couple photosynthetic electron transport to H(2) production. Although the application of genetic engineering to improve energy production phenotypes in eukaryotic microalgae is in its infancy, significant advances in the development of genetic manipulation tools have recently been achieved with microalgal model systems and are being used to manipulate central carbon metabolism in these organisms. It is likely that many of these advances can be extended to industrially relevant organisms. This review is focused on potential avenues of genetic engineering that may be undertaken in order to improve microalgae as a biofuel platform for the production of biohydrogen, starch-derived alcohols, diesel fuel surrogates, and/or alkanes.
Collapse
Affiliation(s)
- Randor Radakovits
- Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois St., Golden, Colorado 80401, and
| | - Robert E. Jinkerson
- Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois St., Golden, Colorado 80401, and
| | - Al Darzins
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois St., Golden, Colorado 80401, and
| |
Collapse
|
50
|
Beer LL, Boyd ES, Peters JW, Posewitz MC. Engineering algae for biohydrogen and biofuel production. Curr Opin Biotechnol 2009; 20:264-71. [DOI: 10.1016/j.copbio.2009.06.002] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 06/02/2009] [Accepted: 06/03/2009] [Indexed: 01/11/2023]
|