1
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Eudes A, Lin CY, De Ben C, Ortega J, Lee MY, Chen YC, Li G, Putnam DH, Mortimer JC, Ronald PC, Scown CD, Scheller HV. Field performance of switchgrass plants engineered for reduced recalcitrance. FRONTIERS IN PLANT SCIENCE 2023; 14:1181035. [PMID: 37324714 PMCID: PMC10266223 DOI: 10.3389/fpls.2023.1181035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/26/2023] [Indexed: 06/17/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a promising perennial bioenergy crop that achieves high yields with relatively low nutrient and energy inputs. Modification of cell wall composition for reduced recalcitrance can lower the costs of deconstructing biomass to fermentable sugars and other intermediates. We have engineered overexpression of OsAT10, encoding a rice BAHD acyltransferase and QsuB, encoding dehydroshikimate dehydratase from Corynebacterium glutamicum, to enhance saccharification efficiency in switchgrass. These engineering strategies demonstrated low lignin content, low ferulic acid esters, and increased saccharification yield during greenhouse studies in switchgrass and other plant species. In this work, transgenic switchgrass plants overexpressing either OsAT10 or QsuB were tested in the field in Davis, California, USA for three growing seasons. No significant differences in the content of lignin and cell wall-bound p-coumaric acid or ferulic acid were detected in transgenic OsAT10 lines compared with the untransformed Alamo control variety. However, the transgenic overexpressing QsuB lines had increased biomass yield and slightly increased biomass saccharification properties compared to the control plants. This work demonstrates good performance of engineered plants in the field, and also shows that the cell wall changes in the greenhouse were not replicated in the field, emphasizing the need to validate engineered plants under relevant field conditions.
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Affiliation(s)
- Aymerick Eudes
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Chien-Yuan Lin
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Christopher De Ben
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Department of Plant Sciences, University of California, Davis, CA, United States
| | - Jasmine Ortega
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Mi Yeon Lee
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Yi-Chun Chen
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Guotian Li
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, United States
| | - Daniel H. Putnam
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Department of Plant Sciences, University of California, Davis, CA, United States
| | - Jenny C. Mortimer
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA, Australia
| | - Pamela C. Ronald
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, United States
| | - Corinne D. Scown
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Energy Analysis and Environmental Impacts Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Energy & Biosciences Institute, University of California, Berkeley, CA, United States
| | - Henrik V. Scheller
- Feedstocks and Life-Cycle, Economics and Agronomy Divisions, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA, United States
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2
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Mehta N, Meng Y, Zare R, Kamenetsky-Goldstein R, Sattely E. A developmental gradient reveals biosynthetic pathways to eukaryotic toxins in monocot geophytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.12.540595. [PMID: 37214939 PMCID: PMC10197729 DOI: 10.1101/2023.05.12.540595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Numerous eukaryotic toxins that accumulate in geophytic plants are valuable in the clinic, yet their biosynthetic pathways have remained elusive. A lead example is the >150 Amaryllidaceae alkaloids (AmAs) including galantamine, an FDA-approved treatment for Alzheimer's disease. We show that while AmAs accumulate to high levels in many tissues in daffodils, biosynthesis is localized to nascent, growing tissue at the base of leaves. A similar trend is found for the production of steroidal alkaloids (e.g. cyclopamine) in corn lily. This model of active biosynthesis enabled elucidation of a complete set of biosynthetic genes for the production of AmAs. Taken together, our work sheds light on the developmental and enzymatic logic of diverse alkaloid biosynthesis in daffodil. More broadly, it suggests a paradigm for biosynthesis regulation in monocot geophytes where plants are protected from herbivory through active charging of newly formed cells with eukaryotic toxins that persist as aboveground tissue develops.
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Affiliation(s)
- Niraj Mehta
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Yifan Meng
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Richard Zare
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | | | - Elizabeth Sattely
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
- HHMI, Stanford University, Stanford, CA 94305
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3
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Lin CY, Geiselman GM, Liu D, Magurudeniya HD, Rodriguez A, Chen YC, Pidatala V, Unda F, Amer B, Baidoo EEK, Mansfield SD, Simmons BA, Singh S, Scheller HV, Gladden JM, Eudes A. Evaluation of engineered low-lignin poplar for conversion into advanced bioproducts. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:145. [PMID: 36567331 PMCID: PMC9790118 DOI: 10.1186/s13068-022-02245-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 12/10/2022] [Indexed: 12/26/2022]
Abstract
BACKGROUND Lignocellulosic resources are promising feedstocks for the manufacture of bio-based products and bioenergy. However, the inherent recalcitrance of biomass to conversion into simple sugars currently hinders the deployment of advanced bioproducts at large scale. Lignin is a primary contributor to biomass recalcitrance as it protects cell wall polysaccharides from degradation and can inhibit hydrolytic enzymes via non-productive adsorption. Several engineering strategies have been designed to reduce lignin or modify its monomeric composition. For example, expression of bacterial 3-dehydroshikimate dehydratase (QsuB) in poplar trees resulted in a reduction in lignin due to redirection of metabolic flux toward 3,4-dihydroxybenzoate at the expense of lignin. This reduction was accompanied with remarkable changes in the pools of aromatic compounds that accumulate in the biomass. RESULTS The impact of these modifications on downstream biomass deconstruction and conversion into advanced bioproducts was evaluated in the current study. Using ionic liquid pretreatment followed by enzymatic saccharification, biomass from engineered trees released more glucose and xylose compared to wild-type control trees under optimum conditions. Fermentation of the resulting hydrolysates using Rhodosporidium toruloides strains engineered to produce α-bisabolene, epi-isozizaene, and fatty alcohols showed no negative impact on cell growth and yielded higher titers of bioproducts (as much as + 58%) in the case of QsuB transgenics trees. CONCLUSION Our data show that low-recalcitrant poplar biomass obtained with the QsuB technology has the potential to improve the production of advanced bioproducts.
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Affiliation(s)
- Chien-Yuan Lin
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Gina M. Geiselman
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94550 USA ,DOE, Agile BioFoundry, Emeryville, CA 94608 USA
| | - Di Liu
- grid.474523.30000000403888279Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94550 USA ,DOE, Agile BioFoundry, Emeryville, CA 94608 USA
| | - Harsha D. Magurudeniya
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94550 USA
| | - Alberto Rodriguez
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94550 USA ,DOE, Agile BioFoundry, Emeryville, CA 94608 USA
| | - Yi-Chun Chen
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Venkataramana Pidatala
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Faride Unda
- grid.17091.3e0000 0001 2288 9830Department of Wood Science, University of British Columbia, Vancouver, BC Canada
| | - Bashar Amer
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Edward E. K. Baidoo
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Shawn D. Mansfield
- grid.17091.3e0000 0001 2288 9830Department of Wood Science, University of British Columbia, Vancouver, BC Canada ,grid.454753.40000 0004 0520 2998DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, WI 53726 USA
| | - Blake A. Simmons
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Seema Singh
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Department of Bioresources and Environmental Security, Sandia National Laboratories, Livermore, CA 94550 USA
| | - Henrik V. Scheller
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - John M. Gladden
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.474523.30000000403888279Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94550 USA ,DOE, Agile BioFoundry, Emeryville, CA 94608 USA
| | - Aymerick Eudes
- grid.451372.60000 0004 0407 8980DOE Joint BioEnergy Institute, Emeryville, CA 94608 USA ,grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
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4
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Lin CY, Tian Y, Nelson-Vasilchik K, Hague J, Kakumanu R, Lee MY, Pidatala VR, Trinh J, De Ben CM, Dalton J, Northen TR, Baidoo EEK, Simmons BA, Gladden JM, Scown CD, Putnam DH, Kausch AP, Scheller HV, Eudes A. Engineering sorghum for higher 4-hydroxybenzoic acid content. Metab Eng Commun 2022; 15:e00207. [PMID: 36188638 PMCID: PMC9519784 DOI: 10.1016/j.mec.2022.e00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/25/2022] [Accepted: 09/19/2022] [Indexed: 11/01/2022] Open
Abstract
Engineering bioenergy crops to accumulate coproducts in planta can increase the value of lignocellulosic biomass and enable a sustainable bioeconomy. In this study, we engineered sorghum with a bacterial gene encoding a chorismate pyruvate-lyase (ubiC) to reroute the plastidial pool of chorismate from the shikimate pathway into the valuable compound 4-hydroxybenzoic acid (4-HBA). A gene encoding a feedback-resistant version of 3-deoxy-d-arabino-heptulonate-7-phosphate synthase (aroG) was also introduced in an attempt to increase the carbon flux through the shikimate pathway. At the full maturity and senesced stage, two independent lines that co-express ubiC and aroG produced 1.5 and 1.7 dw% of 4-HBA in biomass, which represents 36- and 40-fold increases compared to the titer measured in wildtype. The two transgenic lines showed no obvious phenotypes, growth defects, nor alteration of cell wall polysaccharide content when cultivated under controlled conditions. In the field, when harvested before grain maturity, transgenic lines contained 0.8 and 1.2 dw% of 4-HBA, which represent economically relevant titers based on recent technoeconomic analysis. Only a slight reduction (11-15%) in biomass yield was observed in transgenics grown under natural environment. This work provides the first metabolic engineering steps toward 4-HBA overproduction in the bioenergy crop sorghum to improve the economics of biorefineries by accumulating a value-added coproduct that can be recovered from biomass and provide an additional revenue stream.
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Affiliation(s)
- Chien-Yuan Lin
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yang Tian
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Joel Hague
- Department of Cell and Molecular Biology, University of Rhode Island, Rhode Island, RI, 02892, USA
| | - Ramu Kakumanu
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mi Yeon Lee
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Venkataramana R Pidatala
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jessica Trinh
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Christopher M De Ben
- Department of Plant Sciences, University of California-Davis, Davis, CA, 95616, USA
| | - Jutta Dalton
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Trent R Northen
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edward E K Baidoo
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Blake A Simmons
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John M Gladden
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Corinne D Scown
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Energy & Biosciences Institute, University of California-Berkeley, Berkeley, CA, 94720, USA.,Energy Analysis and Environmental Impacts Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Daniel H Putnam
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Department of Plant Sciences, University of California-Davis, Davis, CA, 95616, USA
| | - Albert P Kausch
- Department of Cell and Molecular Biology, University of Rhode Island, Rhode Island, RI, 02892, USA
| | - Henrik V Scheller
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Aymerick Eudes
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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5
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Comparing in planta accumulation with microbial routes to set targets for a cost-competitive bioeconomy. Proc Natl Acad Sci U S A 2022; 119:e2122309119. [PMID: 35858445 PMCID: PMC9335188 DOI: 10.1073/pnas.2122309119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The establishment of a carbon-negative bioeconomy that eliminates the need for crude oil will require a range of bioproducts. Accumulating value-added bioproducts directly in bioenergy crops can be an important strategy for enabling economically competitive biorefineries that produce a range of renewable fuels and replacements for petrochemicals. However, microbial chassis may have advantages over plants for some products. To date, there has been no systematic analysis aimed at comparing microbial production routes with in planta accumulation to establish breakeven targets for yields and accumulation rates. In this study, we provide generalizable insights into these breakeven points by exploring four bioproducts (4-hydroxybenzoic acid [4-HBA], 2-pyrone-4,6-dicarboxylic acid [PDC], muconic acid, and catechol) currently produced both in plants and by microbial hosts. Plants and microbes share common metabolic pathways for producing a range of bioproducts that are potentially foundational to the future bioeconomy. However, in planta accumulation and microbial production of bioproducts have never been systematically compared on an economic basis to identify optimal routes of production. A detailed technoeconomic analysis of four exemplar compounds (4-hydroxybenzoic acid [4-HBA], catechol, muconic acid, and 2-pyrone-4,6-dicarboxylic acid [PDC]) is conducted with the highest reported yields and accumulation rates to identify economically advantaged platforms and breakeven targets for plants and microbes. The results indicate that in planta mass accumulation ranging from 0.1 to 0.3 dry weight % (dwt%) can achieve costs comparable to microbial routes operating at 40 to 55% of maximum theoretical yields. These yields and accumulation rates are sufficient to be cost competitive if the products are sold at market prices consistent with specialty chemicals ($20 to $50/kg). Prices consistent with commodity chemicals will require an order-of-magnitude-greater accumulation rate for plants and/or yields nearing theoretical maxima for microbial production platforms. This comparative analysis revealed that the demonstrated accumulation rates of 4-HBA (3.2 dwt%) and PDC (3.0 dwt%) in engineered plants vastly outperform microbial routes, even if microbial platforms were to reach theoretical maximum yields. Their recovery and sale as part of a lignocellulosic biorefinery could enable biofuel prices to be competitive with petroleum. Muconic acid and catechol, in contrast, are currently more attractive when produced microbially using a sugar feedstock. Ultimately, both platforms can play an important role in replacing fossil-derived products.
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6
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Cheng Y, Kuboyama K, Akasaka S, Araki T, Masai E, Nakamura M, Michinobu T. Polyurethanes based on lignin-derived metabolic intermediate with strong adhesion to metals. Polym Chem 2022. [DOI: 10.1039/d2py01128j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Polyurethanes based on lignin-derived 2-pyrone-4,6-dicarboxylic acid (PDC) were successfully synthesized in one-pot, and their thermal, mechanical, and adhesive properties were investigated.
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Affiliation(s)
- Ye Cheng
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Keiichi Kuboyama
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Shuichi Akasaka
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Takuma Araki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masaya Nakamura
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Tsuyoshi Michinobu
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
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7
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Tian Y, Lin CY, Park JH, Wu CY, Kakumanu R, Pidatala VR, Vuu KM, Rodriguez A, Shih PM, Baidoo EEK, Temple S, Simmons BA, Gladden JM, Scheller HV, Eudes A. Overexpression of the rice BAHD acyltransferase AT10 increases xylan-bound p-coumarate and reduces lignin in Sorghum bicolor. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:217. [PMID: 34801067 PMCID: PMC8606057 DOI: 10.1186/s13068-021-02068-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/06/2021] [Indexed: 05/14/2023]
Abstract
BACKGROUND The development of bioenergy crops with reduced recalcitrance to enzymatic degradation represents an important challenge to enable the sustainable production of advanced biofuels and bioproducts. Biomass recalcitrance is partly attributed to the complex structure of plant cell walls inside which cellulose microfibrils are protected by a network of hemicellulosic xylan chains that crosslink with each other or with lignin via ferulate (FA) bridges. Overexpression of the rice acyltransferase OsAT10 is an effective bioengineering strategy to lower the amount of FA involved in the formation of cell wall crosslinks and thereby reduce cell wall recalcitrance. The annual crop sorghum represents an attractive feedstock for bioenergy purposes considering its high biomass yields and low input requirements. Although we previously validated the OsAT10 engineering approach in the perennial bioenergy crop switchgrass, the effect of OsAT10 expression on biomass composition and digestibility in sorghum remains to be explored. RESULTS We obtained eight independent sorghum (Sorghum bicolor (L.) Moench) transgenic lines with a single copy of a construct designed for OsAT10 expression. Consistent with the proposed role of OsAT10 in acylating arabinosyl residues on xylan with p-coumarate (pCA), a higher amount of p-coumaroyl-arabinose was released from the cell walls of these lines upon hydrolysis with trifluoroacetic acid. However, no major changes were observed regarding the total amount of pCA or FA esters released from cell walls upon mild alkaline hydrolysis. Certain diferulate (diFA) isomers identified in alkaline hydrolysates were increased in some transgenic lines. The amount of the main cell wall monosaccharides glucose, xylose, and arabinose was unaffected. The transgenic lines showed reduced lignin content and their biomass released higher yields of sugars after ionic liquid pretreatment followed by enzymatic saccharification. CONCLUSIONS Expression of OsAT10 in sorghum leads to an increase of xylan-bound pCA without reducing the overall content of cell wall FA esters. Nevertheless, the amount of total cell wall pCA remains unchanged indicating that most pCA is ester-linked to lignin. Unlike other engineered plants overexpressing OsAT10 or a phylogenetically related acyltransferase with similar putative function, the improvements of biomass saccharification efficiency in sorghum OsAT10 lines are likely the result of lignin reductions rather than reductions of cell wall-bound FA. These results also suggest a relationship between xylan-bound pCA and lignification in cell walls.
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Affiliation(s)
- Yang Tian
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Chien-Yuan Lin
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | | | - Chuan-Yin Wu
- Forage Genetics International, West Salem, WI 54669 USA
| | - Ramu Kakumanu
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Venkataramana R. Pidatala
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Khanh M. Vuu
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Alberto Rodriguez
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94551 USA
| | - Patrick M. Shih
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA 94720 USA
| | - Edward E. K. Baidoo
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | | | - Blake A. Simmons
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - John M. Gladden
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, CA 94551 USA
| | - Henrik V. Scheller
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA 94720 USA
| | - Aymerick Eudes
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
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