1
|
Anthony WE, Geng W, Diao J, Carr RR, Wang B, Ning J, Moon TS, Dantas G, Zhang F. Increased triacylglycerol production in Rhodococcus opacus by overexpressing transcriptional regulators. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:83. [PMID: 38898475 PMCID: PMC11186279 DOI: 10.1186/s13068-024-02523-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024]
Abstract
Lignocellulosic biomass is currently underutilized, but it offers promise as a resource for the generation of commercial end-products, such as biofuels, detergents, and other oleochemicals. Rhodococcus opacus PD630 is an oleaginous, Gram-positive bacterium with an exceptional ability to utilize recalcitrant aromatic lignin breakdown products to produce lipid molecules such as triacylglycerols (TAGs), which are an important biofuel precursor. Lipid carbon storage molecules accumulate only under growth-limiting low nitrogen conditions, representing a significant challenge toward using bacterial biorefineries for fuel precursor production. In this work, we screened overexpression of 27 native transcriptional regulators for their abilities to improve lipid accumulation under nitrogen-rich conditions, resulting in three strains that accumulate increased lipids, unconstrained by nitrogen availability when grown in phenol or glucose. Transcriptomic analyses revealed that the best strain (#13) enhanced FA production via activation of the β-ketoadipate pathway. Gene deletion experiments confirm that lipid accumulation in nitrogen-replete conditions requires reprogramming of phenylalanine metabolism. By generating mutants decoupling carbon storage from low nitrogen environments, we move closer toward optimizing R. opacus for efficient bioproduction on lignocellulosic biomass.
Collapse
Affiliation(s)
- Winston E Anthony
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Earth and Biological Systems Directorate, Pacific Northwest National Laboratory, Seattle, USA
| | - Weitao Geng
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Jinjin Diao
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Rhiannon R Carr
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Bin Wang
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jie Ning
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St Louis, MO, 63110, USA.
- Department of Pediatrics, Washington University School of Medicine in St Louis, St Louis, MO, 63110, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Institute of Materials Science & Engineering, Washington University in St Louis, St Louis, MO, 63130, USA.
| |
Collapse
|
2
|
Gu J, Qiu Q, Yu Y, Sun X, Tian K, Chang M, Wang Y, Zhang F, Huo H. Bacterial transformation of lignin: key enzymes and high-value products. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:2. [PMID: 38172947 PMCID: PMC10765951 DOI: 10.1186/s13068-023-02447-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024]
Abstract
Lignin, a natural organic polymer that is recyclable and inexpensive, serves as one of the most abundant green resources in nature. With the increasing consumption of fossil fuels and the deterioration of the environment, the development and utilization of renewable resources have attracted considerable attention. Therefore, the effective and comprehensive utilization of lignin has become an important global research topic, with the goal of environmental protection and economic development. This review focused on the bacteria and enzymes that can bio-transform lignin, focusing on the main ways that lignin can be utilized to produce high-value chemical products. Bacillus has demonstrated the most prominent effect on lignin degradation, with 89% lignin degradation by Bacillus cereus. Furthermore, several bacterial enzymes were discussed that can act on lignin, with the main enzymes consisting of dye-decolorizing peroxidases and laccase. Finally, low-molecular-weight lignin compounds were converted into value-added products through specific reaction pathways. These bacteria and enzymes may become potential candidates for efficient lignin degradation in the future, providing a method for lignin high-value conversion. In addition, the bacterial metabolic pathways convert lignin-derived aromatics into intermediates through the "biological funnel", achieving the biosynthesis of value-added products. The utilization of this "biological funnel" of aromatic compounds may address the heterogeneous issue of the aromatic products obtained via lignin depolymerization. This may also simplify the separation of downstream target products and provide avenues for the commercial application of lignin conversion into high-value products.
Collapse
Affiliation(s)
- Jinming Gu
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Qing Qiu
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Yue Yu
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Xuejian Sun
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Kejian Tian
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Menghan Chang
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Yibing Wang
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Fenglin Zhang
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China
| | - Hongliang Huo
- School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun, 130117, China.
- Engineering Lab for Water Pollution Control and Resources Recovery of Jilin Province, Changchun, 130117, China.
- Engineering Research Center of Low-Carbon Treatment and Green Development of Polluted Water in Northeast China, Ministry of Education, Changchun, 130117, China.
| |
Collapse
|
3
|
Zhao ZM, Liu ZH, Zhang T, Meng R, Gong Z, Li Y, Hu J, Ragauskas AJ, Li BZ, Yuan YJ. Unleashing the capacity of Rhodococcus for converting lignin into lipids. Biotechnol Adv 2024; 70:108274. [PMID: 37913947 DOI: 10.1016/j.biotechadv.2023.108274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/11/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
Bioconversion of bioresources/wastes (e.g., lignin, chemical pulping byproducts) represents a promising approach for developing a bioeconomy to help address growing energy and materials demands. Rhodococcus, a promising microbial strain, utilizes numerous carbon sources to produce lipids, which are precursors for synthesizing biodiesel and aviation fuels. However, compared to chemical conversion, bioconversion involves living cells, which is a more complex system that needs further understanding and upgrading. Various wastes amenable to bioconversion are reviewed herein to highlight the potential of Rhodococci for producing lipid-derived bioproducts. In light of the abundant availability of these substrates, Rhodococcus' metabolic pathways converting them to lipids are analyzed from a "beginning-to-end" view. Based on an in-depth understanding of microbial metabolic routes, genetic modifications of Rhodococcus by employing emerging tools (e.g., multiplex genome editing, biosensors, and genome-scale metabolic models) are presented for promoting the bioconversion. Co-solvent enhanced lignocellulose fractionation (CELF) strategy facilitates the generation of a lignin-derived aromatic stream suitable for the Rhodococcus' utilization. Novel alkali sterilization (AS) and elimination of thermal sterilization (ETS) approaches can significantly enhance the bioaccessibility of lignin and its derived aromatics in aqueous fermentation media, which promotes lipid titer significantly. In order to achieve value-added utilization of lignin, biodiesel and aviation fuel synthesis from lignin and lipids are further discussed. The possible directions for unleashing the capacity of Rhodococcus through synergistically modifying microbial strains, substrates, and fermentation processes are proposed toward a sustainable biological lignin valorization.
Collapse
Affiliation(s)
- Zhi-Min Zhao
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Zhi-Hua Liu
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Tongtong Zhang
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Rongqian Meng
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Zhiqun Gong
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yibing Li
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Jing Hu
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Arthur J Ragauskas
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, United States; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN 37996, United States.
| | - Bing-Zhi Li
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Ying-Jin Yuan
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| |
Collapse
|
4
|
Xue L, Zhao Y, Li L, Rao X, Chen X, Ma F, Yu H, Xie S. A key O-demethylase in the degradation of guaiacol by Rhodococcus opacus PD630. Appl Environ Microbiol 2023; 89:e0052223. [PMID: 37800939 PMCID: PMC10617553 DOI: 10.1128/aem.00522-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/24/2023] [Indexed: 10/07/2023] Open
Abstract
Rhodococcus opacus PD630 is a high oil-producing strain with the ability to convert lignin-derived aromatics to high values, but limited research has been done to elucidate its conversion pathway, especially the upper pathways. In this study, we focused on the upper pathways and demethylation mechanism of lignin-derived aromatics metabolism by R. opacus PD630. The results of the aromatic carbon resource utilization screening showed that R. opacus PD630 had a strong degradation capacity to the lignin-derived methoxy-containing aromatics, such as guaiacol, 3,4-veratric acid, anisic acid, isovanillic acid, and vanillic acid. The gene of gcoAR, which encodes cytochrome P450, showed significant up-regulation when R. opacus PD630 grew on diverse aromatics. Deletion mutants of gcoAR and its partner protein gcoBR resulted in the strain losing the ability to grow on guaiacol, but no significant difference to the other aromatics. Only co-complementation alone of gcoAR and gcoBR restored the strain's ability to utilize guaiacol, demonstrating that both genes were equally important in the utilization of guaiacol. In vitro assays further revealed that GcoAR could convert guaiacol and anisole to catechol and phenol, respectively, with the production of formaldehyde as a by-product. The study provided robust evidence to reveal the molecular mechanism of R. opacus PD630 on guaiacol metabolism and offered a promising study model for dissecting the demethylation process of lignin-derived aromatics in microbes.IMPORTANCEAryl-O-demethylation is believed to be the key rate-limiting step in the catabolism of heterogeneous lignin-derived aromatics in both native and engineered microbes. However, the mechanisms of O-demethylation in lignin-derived aromatic catabolism remain unclear. Notably, guaiacol, the primary component unit of lignin, lacks in situ demonstration and illustration of the molecular mechanism of guaiacol O-demethylation in lignin-degrading bacteria. This is the first study to illustrate the mechanism of guaiacol metabolism by R. opacus PD630 in situ as well as characterize the purified key O-demethylase in vitro. This study provided further insight into the lignin metabolic pathway of R. opacus PD630 and could guide the design of an efficient biocatalytic system for lignin valorization.
Collapse
Affiliation(s)
- Le Xue
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yiquan Zhao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ling Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xinran Rao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xinjie Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Fuying Ma
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hongbo Yu
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shangxian Xie
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| |
Collapse
|
5
|
Sun S, Li F, Li M, Zhang W, Jiang Z, Zhao H, Pu Y, Ragauskas AJ, Dai SY, Zhang X, Yu H, Yuan JS, Xie S. Lytic polysaccharide monooxygenase synergized with lignin-degrading enzymes for efficient lignin degradation. iScience 2023; 26:107870. [PMID: 37766973 PMCID: PMC10520884 DOI: 10.1016/j.isci.2023.107870] [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: 12/05/2022] [Revised: 05/09/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Even though the discovery of lytic polysaccharide monooxygenases (LPMOs) has fundamentally shifted our understanding of biomass degradation, most of the current studies focused on their roles in carbohydrate oxidation. However, no study demonstrated if LPMO could directly participate to the process of lignin degradation in lignin-degrading microbes. This study showed that LPMO could synergize with lignin-degrading enzymes for efficient lignin degradation in white-rot fungi. The transcriptomics analysis of fungi Irpex lacteus and Dichomitus squalens during their lignocellulosic biomass degradation processes surprisingly highlighted that LPMOs co-regulated with lignin-degrading enzymes, indicating their more versatile roles in the redox network. Biochemical analysis further confirmed that the purified LPMO from I. lacteus CD2 could use diverse electron donors to produce H2O2, drive Fenton reaction, and synergize with manganese peroxidase for lignin oxidation. The results thus indicated that LPMO might uniquely leverage the redox network toward dynamic and efficient degradation of different cell wall components.
Collapse
Affiliation(s)
- Su Sun
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- College of Urban Construction, Wuchang Shouyi University, Wuhan 430064, China
| | - Fei Li
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Department of Bioengineering, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Muzi Li
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Texas A&M Agrilife Synthetic, Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Wenqian Zhang
- Texas A&M Agrilife Synthetic, Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Zhenxiong Jiang
- Texas A&M Agrilife Synthetic, Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Honglu Zhao
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yunqiao Pu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Arthur J. Ragauskas
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Chemical and Biomolecular Engineering, Department of Forestry, Wildlife, and Fisheries, University of Tennessee, Knoxville, TN 37996, USA
| | - Susie Y. Dai
- Texas A&M Agrilife Synthetic, Systems Biology Innovation Hub, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Xiaoyu Zhang
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hongbo Yu
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Joshua S. Yuan
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Shangxian Xie
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
6
|
Shen Y, Zeng Z, Yue X, Li H, Bonnet H, Zhou L, Zhuang WQ. The impact of perfluorooctanoic acid shock on hydrogen-driven nitrate and arsenate removal. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122261. [PMID: 37499971 DOI: 10.1016/j.envpol.2023.122261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 07/23/2023] [Accepted: 07/24/2023] [Indexed: 07/29/2023]
Abstract
Perfluorooctanoic acid (PFOA) is a type of toxic per- and poly-fluoroalkyl substance (PFAS) commonly found in groundwater due to its use in firefighting and industrial applications. The main purpose of this study was to investigate the influence of PFOA shock on the biological performance of a hydrogen-driven bioreactor for nitrate and arsenate removal. Four hydrogen-driven removal reactors (HdBRs) used for the simultaneous removal of nitrate and arsenal were operated with concentrations of either 0, 1, 5, and 10 mg/L of PFOA to induce shock on the systems and examine the corresponding bacterial response. Our results showed that PFOA shock inhibited and decreased the maximum hydrogen-driven arsenate removal rate. Principal Component Analysis (PCA) confirmed that this performance decrease occurred due to a bacterial strike triggered by PFOA shock. PFOA toxicity also led to protein secretion and sludge density decreases. Bacterial analyses showed shifts in the community population due to PFOA shock. The dominant bacteria phylum Proteobacteria became more abundant, from 41.24% originally to 48.29% after exposure to 10 mg/L of PFOA. Other phyla, such as Euryarchaeota and Bacteroidetes, were more tolerant to PFOA shock. Although some of the predominant species within the sludge of each HdBR exhibited a decline, other species with similar functions persisted and assumed the functional responsibilities previously held by the dominant species.
Collapse
Affiliation(s)
- Yichang Shen
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Zhihang Zeng
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xi Yue
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Haixiang Li
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin, Guangxi, 541004, China
| | - Hukerenui Bonnet
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland, 1142, New Zealand
| | - Lijie Zhou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Wei-Qin Zhuang
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland, 1142, New Zealand
| |
Collapse
|
7
|
Zhao ZM, Meng X, Pu Y, Li M, Li Y, Zhang Y, Chen F, Ragauskas AJ. Bioconversion of Homogeneous Linear C-Lignin to Polyhydroxyalkanoates. Biomacromolecules 2023; 24:3996-4004. [PMID: 37555845 DOI: 10.1021/acs.biomac.3c00288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The bioconversion of homogeneous linear catechyl lignin (C-lignin) to polyhydroxyalkanoates (PHA) was examined for the first time in this study. C-lignins from vanilla, euphorbia, and candlenut seed coats (denoted as C1, C2, and C3, respectively) varied in their molecular structures, which showed different molecular weight distributions, etherification degrees, and contents of hydroxyl groups. A notable amount of nonetherified catechol units existed within C1 and C2 lignins, and these catechol units were consumed during fermentation. These results suggested that the nonetherified catechol structure was readily converted by Pseudomonas putida KT2440. Since the weight-average molecular weight of C2 raw lignin was 26.7% lower than that of C1, the bioconversion performance of C2 lignin was more outstanding. The P. putida KT2440 cell amount reached the maximum of 9.3 × 107 CFU/mL in the C2 medium, which was 37.9 and 82.4% higher than that in the C1 and C3 medium, respectively. Accordingly, PHA concentration reached 137 mg/L within the C2 medium, which was 41.2 and 149.1% higher than the C1 and C3 medium, respectively. Overall, C-lignin, with a nonetherified catechol structure and low molecular weight, benefits its microbial conversion significantly.
Collapse
Affiliation(s)
- Zhi-Min Zhao
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Yunqiao Pu
- Center for Bioenergy Innovation (CBI), Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Mi Li
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Yibing Li
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yihan Zhang
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Fang Chen
- Center for Bioenergy Innovation (CBI), Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203, United States
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Bioenergy Innovation (CBI), Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| |
Collapse
|
8
|
Lan HN, Liu RY, Liu ZH, Li X, Li BZ, Yuan YJ. Biological valorization of lignin to flavonoids. Biotechnol Adv 2023; 64:108107. [PMID: 36758651 DOI: 10.1016/j.biotechadv.2023.108107] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/12/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023]
Abstract
Lignin is the most affluent natural aromatic biopolymer on the earth, which is the promising renewable source for valuable products to promote the sustainability of biorefinery. Flavonoids are a class of plant polyphenolic secondary metabolites containing the benzene ring structure with various biological activities, which are largely applied in health food, pharmaceutical, and medical fields. Due to the aromatic similarity, microbial conversion of lignin derived aromatics to flavonoids could facilitate flavonoid biosynthesis and promote the lignin valorization. This review thereby prospects a novel valorization route of lignin to high-value natural products and demonstrates the potential advantages of microbial bioconversion of lignin to flavonoids. The biodegradation of lignin polymers is summarized to identify aromatic monomers as momentous precursors for flavonoid synthesis. The biosynthesis pathways of flavonoids in both plants and strains are introduced and compared. After that, the key branch points and important intermediates are clearly discussed in the biosynthesis pathways of flavonoids. Moreover, the most significant enzyme reactions including Claisen condensation, cyclization and hydroxylation are demonstrated in the biosynthesis pathways of flavonoids. Finally, current challenges and potential future strategies are also discussed for transforming lignin into various flavonoids. The holistic microbial conversion routes of lignin to flavonoids could make a sustainable production of flavonoids and improve the feasibility of lignin valorization.
Collapse
Affiliation(s)
- Hai-Na Lan
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Ruo-Ying Liu
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Zhi-Hua Liu
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Xia Li
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Bing-Zhi Li
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
| | - Ying-Jin Yuan
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| |
Collapse
|
9
|
Li YQ, Wang MJ, Luo CB. Highly efficient polyhydroxyalkanoate production from lignin using genetically engineered Halomonas sp. Y3. BIORESOURCE TECHNOLOGY 2023; 370:128526. [PMID: 36572161 DOI: 10.1016/j.biortech.2022.128526] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Lignin degradation represents a significant challenge in biological valorization, but it is suffering from insufficiency, putting barriers to efficient lignin conversion. Herein, the study first develops a highly efficient laccase secretion apparatus, enabling high enzyme activity of 184 U/mL, complementing the biochemical limits on lignin depolymerization well in Halomonas sp. Y3. Further engineering of PHA biosynthesis produces a significantly high PHA titer of 286, 742, and 868 mg/L from alkaline lignin, catechol, and protocatechuate, respectively. The integration of laccase-secretion and PHA production modules enables a record titer of 693 and 1209 mg/L in converting lignin and lignin-containing stream to PHA, respectively. The titer is improved furtherly to 740 and 1314 mg/L by developing a non-sterilized fermentation. This study advances a cheaper and greener production of valuable chemicals from lignin by constructing a biosynthetic platform for PHA production and provides novel insight into the lignin conversion by extremophilic microbes.
Collapse
Affiliation(s)
- Yuan-Qiu Li
- College of Life Science, Leshan Normal University, Leshan 614000, China; College of Life Sciences, Capital Normal University, Beijing 100064, China
| | - Ming-Jun Wang
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Chao-Bing Luo
- College of Life Science, Leshan Normal University, Leshan 614000, China.
| |
Collapse
|
10
|
Tunuhe A, Liu P, Ullah M, Sun S, Xie H, Ma F, Yu H, Zhou Y, Xie S. Fungal-Modified Lignin-Enhanced Physicochemical Properties of Collagen-Based Composite Films. J Fungi (Basel) 2022; 8:jof8121303. [PMID: 36547636 PMCID: PMC9783068 DOI: 10.3390/jof8121303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Renewable and biodegradable materials have attracted broad attention as alternatives to existing conventional plastics, which have caused serious environmental problems. Collagen is a potential material for developing versatile film due to its biosafety, renewability, and biodegradability. However, it is still critical to overcome the low mechanical, antibacterial and antioxidant properties of the collagen film for food packaging applications. To address these limitations, we developed a new technology to prepare composite film by using collagen and fungal-modified APL (alkali pretreatment liquor). In this study, five edible and medical fungi, Cunninghamella echinulata FR3, Pleurotus ostreatus BP3, Ganoderma lucidum EN2, Schizophyllum commune DS1 and Xylariaceae sp. XY were used to modify the APL, and that showed that the modified APL significantly improved the mechanical, antibacterial and antioxidant properties of APL/Collagen composite films. Particularly, the APL modified by BP3, EN2 and XY showed preferable performance in enhancing the properties of the composite films. The tensile strength of the film was increased by 1.5-fold in the presence of the APL modified by EN2. To further understand the effect of fungal-biomodified APL on the properties of the composite films, a correlation analysis between the components of APL and the properties of composite films was conducted and indicated that the content of aromatic functional groups and lignin had a positive correlation with the enhanced mechanical and antioxidant properties of the composite films. In summary, composite films prepared from collagen and fungal biomodified APL showed elevated mechanical, antibacterial and antioxidant properties, and the herein-reported novel technology prospectively possesses great potential application in the food packaging industry.
Collapse
Affiliation(s)
- Alitenai Tunuhe
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Pengyang Liu
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mati Ullah
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Su Sun
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- College of Urban Construction, Wuchang Shouyi University, Wuhan 430074, China
| | - Hua Xie
- Guangxi Shenguan Collagen Technology Research Institute, Guangxi Shenguan Collagen Biological Group, Wuzhou 543000, China
| | - Fuying Ma
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hongbo Yu
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yaxian Zhou
- Guangxi Shenguan Collagen Technology Research Institute, Guangxi Shenguan Collagen Biological Group, Wuzhou 543000, China
- Correspondence: (Y.Z.); (S.X.); Tel.: +86-0774-2035538 (Y.Z.); +86-27-87792108 (S.X.)
| | - Shangxian Xie
- Key Laboratory of Molecular Biophysics of MOE, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Correspondence: (Y.Z.); (S.X.); Tel.: +86-0774-2035538 (Y.Z.); +86-27-87792108 (S.X.)
| |
Collapse
|
11
|
Li F, Zhao Y, Xue L, Ma F, Dai SY, Xie S. Microbial lignin valorization through depolymerization to aromatics conversion. Trends Biotechnol 2022; 40:1469-1487. [PMID: 36307230 DOI: 10.1016/j.tibtech.2022.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 11/05/2022]
Abstract
Lignin is the most abundant source of renewable aromatic biopolymers and its valorization presents significant value for biorefinery sustainability, which promotes the utilization of renewable resources. However, it is challenging to fully convert the structurally complex, heterogeneous, and recalcitrant lignin into high-value products. The in-depth research on the lignin degradation mechanism, microbial metabolic pathways, and rational design of new systems using synthetic biology have significantly accelerated the development of lignin valorization. This review summarizes the key enzymes involved in lignin depolymerization, the mechanisms of microbial lignin conversion, and the lignin valorization application with integrated systems and synthetic biology. Current challenges and future strategies to further study lignin biodegradation and the trends of lignin valorization are also discussed.
Collapse
Affiliation(s)
- Fei Li
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yiquan Zhao
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Le Xue
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Fuying Ma
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Susie Y Dai
- Department of Plant Pathology and Microbiology, Texas A&M University, College station, TX 77843, USA.
| | - Shangxian Xie
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
| |
Collapse
|
12
|
Liu ZH, Li BZ, Yuan JS, Yuan YJ. Creative biological lignin conversion routes toward lignin valorization. Trends Biotechnol 2022; 40:1550-1566. [PMID: 36270902 DOI: 10.1016/j.tibtech.2022.09.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/18/2022] [Accepted: 09/22/2022] [Indexed: 11/05/2022]
Abstract
Lignin, the largest renewable aromatic resource, is a promising alternative feedstock for the sustainable production of various chemicals, fuels, and materials. Despite this potential, lignin is characterized by heterogeneous and macromolecular structures that must be addressed. In this review, we present biological lignin conversion routes (BLCRs) that offer opportunities for overcoming these challenges, making lignin valorization feasible. Funneling heterogeneous aromatics via a 'biological funnel' offers a high-specificity bioconversion route for aromatic platform chemicals. The inherent aromaticity of lignin drives atom-economic functionalization routes toward aromatic natural product generation. By harnessing the ligninolytic capacities of specific microbial systems, powerful aromatic ring-opening routes can be developed to generate various value-added products. Thus, BLCRs hold the promise to make lignin valorization feasible and enable a lignocellulose-based bioeconomy.
Collapse
Affiliation(s)
- Zhi-Hua Liu
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Bing-Zhi Li
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
| | - Joshua S Yuan
- Department of Energy, Environmental, and Chemical Engineering, The McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Ying-Jin Yuan
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| |
Collapse
|
13
|
Li J, Hu C, Arreola-Vargas J, Chen K, Yuan JS. Feedstock design for quality biomaterials. Trends Biotechnol 2022; 40:1535-1549. [PMID: 36273927 DOI: 10.1016/j.tibtech.2022.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
Feedstock design is crucial for lignocellulosic biomass use. Current strategies for feedstock design cannot be readily applied to improve the quality of biomass-based materials, limiting the sustainability and economics of lignocellulosic biorefineries. Recent studies have advanced the understanding of biomass structure-property relationships and discovered several characteristics, such as molecular weight, uniformity, linkage profile, and functional groups, that are critical for manufacturing diverse quality biomaterials. These discoveries call for fundamentally different strategies for feedstock development. Such strategies need to rediscover the roles of monolignol biosynthesis enzymes and leverage lignin polymerization enzymes to achieve precise control of lignin molecular structure. These innovations could transform biomass into feedstock for high-quality biomaterials, addressing essential environmental challenges and empowering the bioeconomy.
Collapse
Affiliation(s)
- Jinghao Li
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Cheng Hu
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Jorge Arreola-Vargas
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Kainan Chen
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Joshua S Yuan
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
| |
Collapse
|
14
|
Wu Z, Peng K, Zhang Y, Wang M, Yong C, Chen L, Qu P, Huang H, Sun E, Pan M. Lignocellulose dissociation with biological pretreatment towards the biochemical platform: A review. Mater Today Bio 2022; 16:100445. [PMID: 36212906 PMCID: PMC9535326 DOI: 10.1016/j.mtbio.2022.100445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/24/2022] [Accepted: 09/27/2022] [Indexed: 11/30/2022]
Abstract
Lignocellulose utilization has been gaining great attention worldwide due to its abundance, accessibility, renewability and recyclability. Destruction and dissociation of the cross-linked, hierarchical structure within cellulose hemicellulose and lignin is the key procedure during chemical utilization of lignocellulose. Of the pretreatments, biological treatment, which can effectively target the complex structures, is attractive due to its mild reaction conditions and environmentally friendly characteristics. Herein, we report a comprehensive review of the current biological pretreatments for lignocellulose dissociation and their corresponding degradation mechanisms. Firstly, we analyze the layered, hierarchical structure of cell wall, and the cross-linked network between cellulose, hemicellulose and lignin, then highlight that the cracking of β-aryl ether is considered the key to lignin degradation because of its dominant position. Secondly, we explore the effect of biological pretreatments, such as fungi, bacteria, microbial consortium, and enzymes, on substrate structure and degradation efficiency. Additionally, combining biological pretreatment with other methods (chemical methods and catalytic materials) may reduce the time necessary for the whole process, which also help to strengthen the lignocellulose dissociation efficiency. Thirdly, we summarize the related applications of lignocellulose, such as fuel production, chemicals platform, and bio-pulping, which could effectively alleviate the energy pressure through bioconversion into high value-added products. Based on reviewing of current progress of lignocellulose pretreatment, the challenges and future prospects are emphasized. Genetic engineering and other technologies to modify strains or enzymes for improved biotransformation efficiency will be the focus of future research.
Collapse
Affiliation(s)
- Zengyou Wu
- College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Kun Peng
- School of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yin Zhang
- College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China
| | - Mei Wang
- School of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Cheng Yong
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Ling Chen
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Ping Qu
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Hongying Huang
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Enhui Sun
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
- School of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, China
- College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Pietermaritzburg Campus), Private Bag X01, Scottsville, 3209, South Africa
- Corresponding author. Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization/Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
| | - Mingzhu Pan
- College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China
- Corresponding author.
| |
Collapse
|
15
|
Coyle H, Wawrousek K. Rhodococcus opacus PD630 Bioconversion of Molasses Desugarized Solubles for Fatty Acid Production. Ind Biotechnol (New Rochelle N Y) 2022. [DOI: 10.1089/ind.2022.0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Hanley Coyle
- Chemical Engineering, University of Wyoming, Laramie, WY 82071
| | - Karen Wawrousek
- Chemical Engineering, University of Wyoming, Laramie, WY 82071
| |
Collapse
|
16
|
Deciphering the transcriptional regulation of the catabolism of lignin-derived aromatics in Rhodococcus opacus PD630. Commun Biol 2022; 5:1109. [PMID: 36261484 DOI: 10.1038/s42003-022-04069-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 10/04/2022] [Indexed: 11/08/2022] Open
Abstract
Rhodococcus opacus PD630 has considerable potential as a platform for valorizing lignin due to its innate "biological funneling" pathways. However, the transcriptional regulation of the aromatic catabolic pathways and the mechanisms controlling aromatic catabolic operons in response to different aromatic mixtures are still underexplored. Here, we identified and studied the transcription factors for aromatic degradation using GFP-based sensors and comprehensive deletion analyses. Our results demonstrate that the funneling pathways for phenol, guaiacol, 4-hydroxybenzoate, and vanillate are controlled by transcriptional activators. The two different branches of the β-ketoadipate pathway, however, are controlled by transcriptional repressors. Additionally, promoter activity assays revealed that the substrate hierarchy in R. opacus may be ascribed to the transcriptional cross-regulation of the individual aromatic funneling pathways. These results provide clues to clarify the molecule-level mechanisms underlying the complex regulation of aromatic catabolism, which facilitates the development of R. opacus as a promising chassis for valorizing lignin.
Collapse
|
17
|
Cai C, Xu Z, Li J, Zhou H, Jin M. Developing
Rhodococcus opacus
and
Sphingobium
sp. co‐culture systems for valorization of lignin‐derived dimers. Biotechnol Bioeng 2022; 119:3162-3177. [DOI: 10.1002/bit.28215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Chenggu Cai
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Zhaoxian Xu
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Jie Li
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Huarong Zhou
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Mingjie Jin
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| |
Collapse
|
18
|
Mattoo AJ, Nonzom S. Endophytes in Lignin Valorization: A Novel Approach. Front Bioeng Biotechnol 2022; 10:895414. [PMID: 35928943 PMCID: PMC9343868 DOI: 10.3389/fbioe.2022.895414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 06/23/2022] [Indexed: 11/29/2022] Open
Abstract
Lignin, one of the essential components of lignocellulosic biomass, comprises an abundant renewable aromatic resource on the planet earth. Although 15%––40% of lignocellulose pertains to lignin, its annual valorization rate is less than 2% which raises the concern to harness and/or develop effective technologies for its valorization. The basic hindrance lies in the structural heterogeneity, complexity, and stability of lignin that collectively makes it difficult to depolymerize and yield common products. Recently, microbial delignification, an eco-friendly and cheaper technique, has attracted the attention due to the diverse metabolisms of microbes that can channelize multiple lignin-based products into specific target compounds. Also, endophytes, a fascinating group of microbes residing asymptomatically within the plant tissues, exhibit marvellous lignin deconstruction potential. Apart from novel sources for potent and stable ligninases, endophytes share immense ability of depolymerizing lignin into desired valuable products. Despite their efficacy, ligninolytic studies on endophytes are meagre with incomplete understanding of the pathways involved at the molecular level. In the recent years, improvement of thermochemical methods has received much attention, however, we lagged in exploring the novel microbial groups for their delignification efficiency and optimization of this ability. This review summarizes the currently available knowledge about endophytic delignification potential with special emphasis on underlying mechanism of biological funnelling for the production of valuable products. It also highlights the recent advancements in developing the most intriguing methods to depolymerize lignin. Comparative account of thermochemical and biological techniques is accentuated with special emphasis on biological/microbial degradation. Exploring potent biological agents for delignification and focussing on the basic challenges in enhancing lignin valorization and overcoming them could make this renewable resource a promising tool to accomplish Sustainable Development Goals (SDG’s) which are supposed to be achieved by 2030.
Collapse
Affiliation(s)
| | - Skarma Nonzom
- *Correspondence: Skarma Nonzom, , orcid.org/0000-0001-9372-7900
| |
Collapse
|
19
|
Liu H, Liu ZH, Zhang RK, Yuan JS, Li BZ, Yuan YJ. Bacterial conversion routes for lignin valorization. Biotechnol Adv 2022; 60:108000. [DOI: 10.1016/j.biotechadv.2022.108000] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 05/31/2022] [Accepted: 05/31/2022] [Indexed: 12/12/2022]
|
20
|
Zhao ZM, Meng X, Scheidemantle B, Pu Y, Liu ZH, Li BZ, Wyman CE, Cai CM, Ragauskas AJ. Cosolvent enhanced lignocellulosic fractionation tailoring lignin chemistry and enhancing lignin bioconversion. BIORESOURCE TECHNOLOGY 2022; 347:126367. [PMID: 34801717 DOI: 10.1016/j.biortech.2021.126367] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Cosolvent Enhanced Lignocellulosic Fractionation (CELF) is an emerging solvolysis pretreatment to fractionate lignocellulosic biomass. Herein, the bioconversion performance of CELF lignin was fully evaluated for the first time. Results showed that CELF lignin possessed higher content of carboxylic acid OH, lower molecular weight, and disappeared β-O-4 and β-5 linkages compared to other two technical lignins including a conventional ethanol organosolv lignin (EOL) and a kraft lignin (KL). Rhodococcus opacus PD630 cell count from CELF lignin fermentation reached the highest value of 3.9 × 107 CFU/mL, representing a 62.5% and 77.3% improvement over EOL and KL, respectively. Correspondingly, lipid yield reached 143 mg/L from CELF lignin, which was 36.2% and 26.5% higher than from EOL and KL, respectively. Principal component analysis (PCA) revealed that more carboxylic acid groups and lower molecular weight contributed to the enhanced bioconversion performance of CELF lignin. This study demonstrates that CELF lignin is a promising candidate for bioconversion.
Collapse
Affiliation(s)
- Zhi-Min Zhao
- School of Ecology and Environment, Inner Mongolia Key Laboratory of Environmental Pollution Control & Wastes Reuse, Inner Mongolia University, Hohhot 010021, China; Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States
| | - Xianzhi Meng
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States
| | - Brent Scheidemantle
- Bourns College of Engineering-Center for Environmental Research and Technology (CE-CERT), University of California, Riverside, CA 92507, United States
| | - Yunqiao Pu
- Center for Bioenergy Innovation (CBI), Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States
| | - Zhi-Hua Liu
- School of Chemical Engineering and Technology, Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Bing-Zhi Li
- School of Chemical Engineering and Technology, Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Charles E Wyman
- Bourns College of Engineering-Center for Environmental Research and Technology (CE-CERT), University of California, Riverside, CA 92507, United States
| | - Charles M Cai
- Bourns College of Engineering-Center for Environmental Research and Technology (CE-CERT), University of California, Riverside, CA 92507, United States
| | - Arthur J Ragauskas
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Center for Bioenergy Innovation (CBI), Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Center for Renewable Carbon, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN 37996, United States.
| |
Collapse
|
21
|
Lin L. Bottom-up synthetic ecology study of microbial consortia to enhance lignocellulose bioconversion. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:14. [PMID: 35418100 PMCID: PMC8822760 DOI: 10.1186/s13068-022-02113-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/28/2022] [Indexed: 01/21/2023]
Abstract
Lignocellulose is the most abundant organic carbon polymer on the earth. Its decomposition and conversion greatly impact the global carbon cycle. Furthermore, it provides feedstock for sustainable fuel and other value-added products. However, it continues to be underutilized, due to its highly recalcitrant and heterogeneric structure. Microorganisms, which have evolved versatile pathways to convert lignocellulose, undoubtedly are at the heart of lignocellulose conversion. Numerous studies that have reported successful metabolic engineering of individual strains to improve biological lignin valorization. Meanwhile, the bottleneck of single strain modification is becoming increasingly urgent in the conversion of complex substrates. Alternatively, increased attention has been paid to microbial consortia, as they show advantages over pure cultures, e.g., high efficiency and robustness. Here, we first review recent developments in microbial communities for lignocellulose bioconversion. Furthermore, the emerging area of synthetic ecology, which is an integration of synthetic biology, ecology, and computational biology, provides an opportunity for the bottom-up construction of microbial consortia. Then, we review different modes of microbial interaction and their molecular mechanisms, and discuss considerations of how to employ these interactions to construct synthetic consortia via synthetic ecology, as well as highlight emerging trends in engineering microbial communities for lignocellulose bioconversion.
Collapse
Affiliation(s)
- Lu Lin
- Institute of Marine Science and Technology, Shandong University, Qingdao, 266237, Shandong, China.
| |
Collapse
|
22
|
Banu Jamaldheen S, Kurade MB, Basak B, Yoo CG, Oh KK, Jeon BH, Kim TH. A review on physico-chemical delignification as a pretreatment of lignocellulosic biomass for enhanced bioconversion. BIORESOURCE TECHNOLOGY 2022; 346:126591. [PMID: 34929325 DOI: 10.1016/j.biortech.2021.126591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Effective pretreatment of lignocellulosic biomass (LCB) is one of the most important steps in biorefinery, ensuring the quality and commercial viability of the overall bioprocess. Lignin recalcitrance in LCB is a major bottleneck in biological conversion as the polymerization of lignin with hemicellulose hinders enzyme accessibility and further bioconversion to fuels and chemicals. Therefore, there is a need to delignify LCB to ease further bioprocessing. The efficiency of delignification, quality and quantity of the desired products, and generation of inhibitors depend upon the type of pretreatment employed. This review summarizes different single and integrated physicochemical pretreatments for delignification. Additionally, conditions required for effective delignification and the advantages and drawbacks of each method were evaluated. Advances in overcoming the recalcitrance of residual lignin to saccharification and the methods to recover lignin after delignification are also discussed. Efficient lignin recovery and valorization strategies provide an avenue for the sustainable lignocellulose biorefinery.
Collapse
Affiliation(s)
- Sumitha Banu Jamaldheen
- Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Mayur B Kurade
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Bikram Basak
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Chang Geun Yoo
- Department of Chemical Engineering, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Kyeong Keun Oh
- Department of Chemical Engineering, Dankook University, Youngin 16890, Gyeonggi-do, Republic of Korea
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Tae Hyun Kim
- Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea.
| |
Collapse
|
23
|
Hu C, Zhao M, Li Q, Liu Z, Hao N, Meng X, Li J, Lin F, Li C, Fang L, Dai SY, Ragauskas AJ, Sue HJ, Yuan JS. Phototunable Lignin Plastics to Enable Recyclability. CHEMSUSCHEM 2021; 14:4260-4269. [PMID: 34258878 DOI: 10.1002/cssc.202101040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/07/2021] [Indexed: 06/13/2023]
Abstract
The accumulation of non-degradable petrochemical plastics imposes a significant threat to the environment and ecosystems. We addressed this challenge by designing a new type of phototunable plastics based on the unique lignin chemistry to enable readily end-life recycling. The advanced material design leveraged the efficient photocatalytic lignin depolymerization by ZnO nanoparticles to build lignin-polymethyl methacrylate (PMMA)-ZnO blends. We first demonstrated the highly effective phototunable lignin depolymerization in the complex polymer blend matrix and explored the molecular mechanisms. The technical barriers of mechanical property and recycling processing were then addressed by a new blend design with lignin core grafted with PMMA polymer. The new process has resulted in a new type of PMMA-g-lignin blend, which significantly improved the mechanical properties, making it comparable to PMMA alone. More importantly, the mechanical properties of the UV-treated blend decreased drastically in the new design, whereas the properties did not reduce in the non-grafted blends upon UV exposure. The results highlighted that the new blend design based on graftization maximized the impact of lignin depolymerization on blend structure and recyclability. Based on the results, we developed a process integrating UV and alkaline treatments to recycle PMMA for plastics and fractionated lignin for bioconversion or other applications in the new phototunable plastics.
Collapse
Affiliation(s)
- Cheng Hu
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Mingzhen Zhao
- Department of Material Science and Engineering, Texas A&M University, College Station, TX 77843, USA
- Polymer Technology Center, Texas A&M University, College Station, TX 77843, USA
| | - Qiang Li
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Zhihua Liu
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
- Current address: College of Chemical Engineering, Tianjin University, Tianjin, P. R. China
| | - Naijia Hao
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA
| | - Jinghao Li
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Furong Lin
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Chenxuan Li
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - Lei Fang
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - Susie Y Dai
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - H J Sue
- Department of Material Science and Engineering, Texas A&M University, College Station, TX 77843, USA
- Polymer Technology Center, Texas A&M University, College Station, TX 77843, USA
| | - Joshua S Yuan
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| |
Collapse
|
24
|
Cai C, Xu Z, Zhou H, Chen S, Jin M. Valorization of lignin components into gallate by integrated biological hydroxylation, O-demethylation, and aryl side-chain oxidation. SCIENCE ADVANCES 2021; 7:eabg4585. [PMID: 34516898 PMCID: PMC8442903 DOI: 10.1126/sciadv.abg4585] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Converting lignin components into a single product is a promising way to upgrade lignin. Here, an efficient biocatalyst was developed to selectively produce gallate from lignin components by integrating three main reactions: hydroxylation, O-demethylation, and aryl side-chain oxidation. A rationally designed hydroxylase system was first introduced into a gallate biodegradation pathway–blocked Rhodococcus opacus mutant so that gallate accumulated from protocatechuate and compounds in its upper pathways. Native and heterologous O-demethylation systems were then used, leading to multiple lignin-derived methoxy aromatics being converted to gallate. Furthermore, an aryl side-chain oxidase was engaged to broaden the substrate spectrum. Consequently, the developed biocatalyst showed that gallate yields as high as 0.407 and 0.630 g of gallate per gram of lignin when alkaline-pretreated lignin and base-depolymerized ammonia fiber explosion lignin were applied as substrates, respectively. These results suggested that this rationally developed biocatalyst enabled the lignin valorization process to be simple and efficient.
Collapse
Affiliation(s)
- Chenggu Cai
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Zhaoxian Xu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Huarong Zhou
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Sitong Chen
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China
- Corresponding author.
| |
Collapse
|
25
|
Liang Y, Wei Y, Jiao S, Yu H. A CRISPR/Cas9-based single-stranded DNA recombineering system for genome editing of Rhodococcus opacus PD630. Synth Syst Biotechnol 2021; 6:200-208. [PMID: 34430726 PMCID: PMC8365321 DOI: 10.1016/j.synbio.2021.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/13/2021] [Accepted: 08/02/2021] [Indexed: 12/01/2022] Open
Abstract
Genome engineering of Rhodococcus opacus PD630, an important microorganism used for the bioconversion of lignin, is currently dependent on inefficient homologous recombination. Although a CRISPR interference procedure for gene repression has previously been developed for R. opacus PD630, a CRISPR/Cas9 system for gene knockout has yet to be reported for the strain. In this study, we found that the cytotoxicity of Cas9 and the deficiency in pathways for repairing DNA double-strand breaks (DSBs) were the major causes of the failure of conventional CRISPR/Cas9 technologies in R. opacus, even when augmented with the recombinases Che9c60 and Che9c61. We successfully developed an efficient single-stranded DNA (ssDNA) recombineering system coupled with CRISPR/Cas9 counter-selection, which facilitated rapid and scarless editing of the R. opacus genome. A two-plasmid system, comprising Cas9 driven by a weak Rhodococcus promoter Pniami, designed to prevent cytotoxicity, and a single-guide RNA (sgRNA) under the control of a strong constitutive promoter, was proven to be appropriate with respect to cleavage function. A novel recombinase, RrRecT derived from a Rhodococcus ruber prophage, was identified for the first time, which facilitated recombination of short ssDNA donors (40–80 nt) targeted to the lagging strand and enabled us to obtain a recombination efficiency up to 103-fold higher than that of endogenous pathways. Finally, by incorporating RrRecT and Cas9 into a single plasmid and then co-transforming cells with sgRNA plasmids and short ssDNA donors, we efficiently achieved gene disruption and base mutation in R. opacus, with editing efficiencies ranging from 22 % to 100 %. Simultaneous disruption of double genes was also confirmed, although at a lower efficiency. This effective genome editing tool will accelerate the engineering of R. opacus metabolism.
Collapse
Affiliation(s)
- Youxiang Liang
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.,Key Laboratory of Industrial Biocatalysis (Tsinghua University), The Ministry of Education, Beijing, 100084, China
| | - Yuwen Wei
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.,Key Laboratory of Industrial Biocatalysis (Tsinghua University), The Ministry of Education, Beijing, 100084, China
| | - Song Jiao
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
| | - Huimin Yu
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.,Key Laboratory of Industrial Biocatalysis (Tsinghua University), The Ministry of Education, Beijing, 100084, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
26
|
Alvarez HM, Hernández MA, Lanfranconi MP, Silva RA, Villalba MS. Rhodococcus as Biofactories for Microbial Oil Production. Molecules 2021; 26:molecules26164871. [PMID: 34443455 PMCID: PMC8401914 DOI: 10.3390/molecules26164871] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 01/20/2023] Open
Abstract
Bacteria belonging to the Rhodococcus genus are frequent components of microbial communities in diverse natural environments. Some rhodococcal species exhibit the outstanding ability to produce significant amounts of triacylglycerols (TAG) (>20% of cellular dry weight) in the presence of an excess of the carbon source and limitation of the nitrogen source. For this reason, they can be considered as oleaginous microorganisms. As occurs as well in eukaryotic single-cell oil (SCO) producers, these bacteria possess specific physiological properties and molecular mechanisms that differentiate them from other microorganisms unable to synthesize TAG. In this review, we summarized several of the well-characterized molecular mechanisms that enable oleaginous rhodococci to produce significant amounts of SCO. Furthermore, we highlighted the ability of these microorganisms to degrade a wide range of carbon sources coupled to lipogenesis. The qualitative and quantitative oil production by rhodococci from diverse industrial wastes has also been included. Finally, we summarized the genetic and metabolic approaches applied to oleaginous rhodococci to improve SCO production. This review provides a comprehensive and integrating vision on the potential of oleaginous rhodococci to be considered as microbial biofactories for microbial oil production.
Collapse
|
27
|
Donini E, Firrincieli A, Cappelletti M. Systems biology and metabolic engineering of Rhodococcus for bioconversion and biosynthesis processes. Folia Microbiol (Praha) 2021; 66:701-713. [PMID: 34215934 PMCID: PMC8449775 DOI: 10.1007/s12223-021-00892-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/12/2021] [Indexed: 11/04/2022]
Abstract
Rhodococcus spp. strains are widespread in diverse natural and anthropized environments thanks to their high metabolic versatility, biodegradation activities, and unique adaptation capacities to several stress conditions such as the presence of toxic compounds and environmental fluctuations. Additionally, the capability of Rhodococcus spp. strains to produce high value-added products has received considerable attention, mostly in relation to lipid accumulation. In relation with this, several works carried out omic studies and genome comparative analyses to investigate the genetic and genomic basis of these anabolic capacities, frequently in association with the bioconversion of renewable resources and low-cost substrates into triacylglycerols. This review is focused on these omic analyses and the genetic and metabolic approaches used to improve the biosynthetic and bioconversion performance of Rhodococcus. In particular, this review summarizes the works that applied heterologous expression of specific genes and adaptive laboratory evolution approaches to manipulate anabolic performance. Furthermore, recent molecular toolkits for targeted genome editing as well as genome-based metabolic models are described here as novel and promising strategies for genome-scaled rational design of Rhodococcus cells for efficient biosynthetic processes application.
Collapse
Affiliation(s)
- Eva Donini
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126, Bologna, Italy
| | - Andrea Firrincieli
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126, Bologna, Italy
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126, Bologna, Italy.
| |
Collapse
|
28
|
Liu ZH, Hao N, Wang YY, Dou C, Lin F, Shen R, Bura R, Hodge DB, Dale BE, Ragauskas AJ, Yang B, Yuan JS. Transforming biorefinery designs with 'Plug-In Processes of Lignin' to enable economic waste valorization. Nat Commun 2021; 12:3912. [PMID: 34162838 PMCID: PMC8222318 DOI: 10.1038/s41467-021-23920-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 05/12/2021] [Indexed: 02/05/2023] Open
Abstract
Biological lignin valorization has emerged as a major solution for sustainable and cost-effective biorefineries. However, current biorefineries yield lignin with inadequate fractionation for bioconversion, yet substantial changes of these biorefinery designs to focus on lignin could jeopardize carbohydrate efficiency and increase capital costs. We resolve the dilemma by designing 'plug-in processes of lignin' with the integration of leading pretreatment technologies. Substantial improvement of lignin bioconversion and synergistic enhancement of carbohydrate processing are achieved by solubilizing lignin via lowering molecular weight and increasing hydrophilic groups, addressing the dilemma of lignin- or carbohydrate-first scenarios. The plug-in processes of lignin could enable minimum polyhydroxyalkanoate selling price at as low as $6.18/kg. The results highlight the potential to achieve commercial production of polyhydroxyalkanoates as a co-product of cellulosic ethanol. Here, we show that the plug-in processes of lignin could transform biorefinery design toward sustainability by promoting carbon efficiency and optimizing the total capital cost.
Collapse
Affiliation(s)
- Zhi-Hua Liu
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Naijia Hao
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA
| | - Yun-Yan Wang
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA
| | - Chang Dou
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
| | - Furong Lin
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Rongchun Shen
- Bioproducts, Sciences, and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, WA, USA
| | - Renata Bura
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
| | - David B Hodge
- Chemical and Biological Engineering Department, Montana State University, Bozeman, MT, USA
| | - Bruce E Dale
- Biomass Conversion Research Laboratory, Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, USA
| | - Arthur J Ragauskas
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Department of Forestry, Wildlife and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Bin Yang
- Bioproducts, Sciences, and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, WA, USA
| | - Joshua S Yuan
- Synthetic and Systems Biology Innovation Hub, Texas A&M University, College Station, TX, USA.
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA.
| |
Collapse
|
29
|
DeLorenzo DM, Diao J, Carr R, Hu Y, Moon TS. An Improved CRISPR Interference Tool to Engineer Rhodococcus opacus. ACS Synth Biol 2021; 10:786-798. [PMID: 33787248 DOI: 10.1021/acssynbio.0c00591] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rhodococcus opacus is a nonmodel bacterium that is well suited for valorizing lignin. Despite recent advances in our systems-level understanding of its versatile metabolism, studies of its gene functions at a single gene level are still lagging. Elucidating gene functions in nonmodel organisms is challenging due to limited genetic engineering tools that are convenient to use. To address this issue, we developed a simple gene repression system based on CRISPR interference (CRISPRi). This gene repression system uses a T7 RNA polymerase system to express a small guide RNA, demonstrating improved repression compared to the previously demonstrated CRISPRi system (i.e., the maximum repression efficiency improved from 58% to 85%). Additionally, our cloning strategy allows for building multiple CRISPRi plasmids in parallel without any PCR step, facilitating the engineering of this GC-rich organism. Using the improved CRISPRi system, we confirmed the annotated roles of four metabolic pathway genes, which had been identified by our previous transcriptomic analysis to be related to the consumption of benzoate, vanillate, catechol, and acetate. Furthermore, we showed our tool's utility by demonstrating the inducible accumulation of muconate that is a precursor of adipic acid, an important monomer for nylon production. While the maximum muconate yield obtained using our tool was 30% of the yield obtained using gene knockout, our tool showed its inducibility and partial repressibility. Our CRISPRi tool will be useful to facilitate functional studies of this nonmodel organism and engineer this promising microbial chassis for lignin valorization.
Collapse
Affiliation(s)
- Drew M. DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Jinjin Diao
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Rhiannon Carr
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Yifeng Hu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| |
Collapse
|
30
|
Liang Y, Yu H. Genetic toolkits for engineering Rhodococcus species with versatile applications. Biotechnol Adv 2021; 49:107748. [PMID: 33823269 DOI: 10.1016/j.biotechadv.2021.107748] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 02/09/2023]
Abstract
Rhodococcus spp. are a group of non-model gram-positive bacteria with diverse catabolic activities and strong adaptive capabilities, which enable their wide application in whole-cell biocatalysis, environmental bioremediation, and lignocellulosic biomass conversion. Compared with model microorganisms, the engineering of Rhodococcus is challenging because of the lack of universal molecular tools, high genome GC content (61% ~ 71%), and low transformation and recombination efficiencies. Nevertheless, because of the high interest in Rhodococcus species for bioproduction, various genetic elements and engineering tools have been recently developed for Rhodococcus spp., including R. opacus, R. jostii, R. ruber, and R. erythropolis, leading to the expansion of the genetic toolkits for Rhodococcus engineering. In this article, we provide a comprehensive review of the important developed genetic elements for Rhodococcus, including shuttle vectors, promoters, antibiotic markers, ribosome binding sites, and reporter genes. In addition, we also summarize gene transfer techniques and strategies to improve transformation efficiency, as well as random and precise genome editing tools available for Rhodococcus, including transposition, homologous recombination, recombineering, and CRISPR/Cas9. We conclude by discussing future trends in Rhodococcus engineering. We expect that more synthetic and systems biology tools (such as multiplex genome editing, dynamic regulation, and genome-scale metabolic models) will be adapted and optimized for Rhodococcus.
Collapse
Affiliation(s)
- Youxiang Liang
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Key Laboratory of Industrial Biocatalysis (Tsinghua University), the Ministry of Education, Beijing 100084, China
| | - Huimin Yu
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Key Laboratory of Industrial Biocatalysis (Tsinghua University), the Ministry of Education, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
31
|
Yaguchi AL, Lee SJ, Blenner MA. Synthetic Biology towards Engineering Microbial Lignin Biotransformation. Trends Biotechnol 2021; 39:1037-1064. [PMID: 33712323 DOI: 10.1016/j.tibtech.2021.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/03/2021] [Accepted: 02/03/2021] [Indexed: 01/19/2023]
Abstract
Lignin is the second most abundant biopolymer on earth and is a major source of aromatic compounds; however, it is vastly underutilized owing to its heterogeneous and recalcitrant nature. Microorganisms have evolved efficient mechanisms that overcome these challenges to depolymerize lignin and funnel complex mixtures of lignin-derived monomers to central metabolites. This review summarizes recent synthetic biology efforts to enhance lignin depolymerization and aromatic catabolism in bacterial and fungal hosts for the production of both natural and novel bioproducts. We also highlight difficulties in engineering complex phenotypes and discuss the outlook for the future of lignin biological valorization.
Collapse
Affiliation(s)
- Allison L Yaguchi
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA
| | - Stephen J Lee
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA
| | - Mark A Blenner
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA; Current address: Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA.
| |
Collapse
|
32
|
Liu H, Qi Y, Zhou P, Ye C, Gao C, Chen X, Liu L. Microbial physiological engineering increases the efficiency of microbial cell factories. Crit Rev Biotechnol 2021; 41:339-354. [PMID: 33541146 DOI: 10.1080/07388551.2020.1856770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Microbial cell factories provide vital platforms for the production of chemicals. Advanced biotechnological toolboxes have been developed to enhance their efficiency. However, these tools have limitations in improving physiological functions, and therefore boosting the efficiency (e.g. titer, rate, and yield) of microbial cell factories remains a challenge. In this review, we propose a strategy of microbial physiological engineering (MPE) to improve the efficiency of microbial cell factories. This strategy integrates tools from synthetic and systems biology to characterize and regulate physiological functions during chemical synthesis. MPE strategies mainly focus on the efficiency of substrate utilization, growth performance, stress tolerance, and the product export capacity of cell factories. In short, this review provides a new framework for resolving the bottlenecks that currently exist in low-efficiency cell factories.
Collapse
Affiliation(s)
- Hui Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Yanli Qi
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Pei Zhou
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Chao Ye
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| |
Collapse
|
33
|
Choi KR, Jiao S, Lee SY. Metabolic engineering strategies toward production of biofuels. Curr Opin Chem Biol 2020; 59:1-14. [DOI: 10.1016/j.cbpa.2020.02.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 10/24/2022]
|
34
|
Zhao ZM, Liu ZH, Pu Y, Meng X, Xu J, Yuan JS, Ragauskas AJ. Emerging Strategies for Modifying Lignin Chemistry to Enhance Biological Lignin Valorization. CHEMSUSCHEM 2020; 13:5423-5432. [PMID: 32750220 DOI: 10.1002/cssc.202001401] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/19/2020] [Indexed: 06/11/2023]
Abstract
Biological lignin valorization represents a promising approach contributing to sustainable and economic biorefineries. The low level of valuable lignin-derived products remains a major challenge hindering the implementation of microbial lignin conversion. Lignin's properties play a significant role in determining the efficiency of lignin bioconversion. To date, despite significant progress in the development of biomass pretreatment, lignin fractionation, and fermentation over the last few decades, little efforts have gone into identifying the ideal lignin substrates for an efficient microbial metabolism. In this Minireview, emerging and state-of-the-art strategies for biomass pretreatment and lignin fractionation are summarized to elaborate their roles in modifying lignin structure for bioconversion. Fermentation strategies aimed at enhancing lignin depolymerization for microbial utilization are systematically reviewed as well. With an improved understanding of the ideal lignin structure elucidated by comprehensive metabolic pathways and/or big data analysis, modifying lignin chemistry could be more directional and effective. Ultimately, together with the progress of fermentation process optimization, biological lignin valorization will become more competitive in biorefineries.
Collapse
Affiliation(s)
- Zhi-Min Zhao
- School of Ecology and Environment, Inner Mongolia Key Laboratory of Environmental Pollution Controlling and Wastes Recycling, Inner Mongolia University, Hohhot, 010021, P. R. China
- Department of Chemical & Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA
| | - Zhi-Hua Liu
- Synthetic and Systems Biology Innovation Hub (SSBiH), Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Yunqiao Pu
- Center for Bioenergy Innovation, Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA
| | - Xianzhi Meng
- Department of Chemical & Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA
| | - Jifei Xu
- School of Ecology and Environment, Inner Mongolia Key Laboratory of Environmental Pollution Controlling and Wastes Recycling, Inner Mongolia University, Hohhot, 010021, P. R. China
| | - Joshua S Yuan
- Synthetic and Systems Biology Innovation Hub (SSBiH), Texas A&M University, College Station, TX 77843, USA
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Arthur J Ragauskas
- Department of Chemical & Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA
- Center for Bioenergy Innovation, Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA
| |
Collapse
|
35
|
Chatterjee A, DeLorenzo DM, Carr R, Moon TS. Bioconversion of renewable feedstocks by Rhodococcus opacus. Curr Opin Biotechnol 2020; 64:10-16. [DOI: 10.1016/j.copbio.2019.08.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/19/2019] [Accepted: 08/25/2019] [Indexed: 12/18/2022]
|
36
|
Wang L, Ni H, Zhang J, Shi Q, Zhang R, Yu H, Li M. Enzymatic treatment improves fast pyrolysis product selectivity of softwood and hardwood lignin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137241. [PMID: 32070898 DOI: 10.1016/j.scitotenv.2020.137241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/08/2020] [Accepted: 02/08/2020] [Indexed: 06/10/2023]
Abstract
Fast pyrolysis of lignin is still struggling in efficiency and scalable utilization. The low product selectivity thereby represents one of the most challenging issues. White-rot fungi have been widely used in bio-pretreatment of lignocellulosic biomass, where ligninolytic enzymes have been evidenced to modify lignin structures and enhance bio-refining efficiency. We thus treated lignin from both softwood (ginkgo) and hardwood (poplar) with enzymatic cocktail from white-rot fungus for fast pyrolysis. Both ginkgo and poplar lignin had much improved product selectivity at lower temperature after enzymatic modification, in particular, the 2-methoxy-phenol production from ginkgo lignin. Besides the improved product selectivity, the residue bio-char from pyrolysis had much improved surface area with more porous structures. Mechanistic study showed that the improvement of lignin pyrolysis products might attribute to demethoxylation and interunit linkage cleavage of lignin during enzymatic treatment. All these results highlighted that the product selectivity and bio-char performances have been synergistically improved by enzymatic treatment, which could thus pave a new way for enhancing fast pyrolysis efficiency. Overall, using softwood and hardwood lignin, this research has presented a new strategy using ligninolytic enzyme to modify lignin for synergistically improving product selectivity and bio-char performances, which opened up a new avenue for lignin valorization.
Collapse
Affiliation(s)
- Lei Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Key Laboratory of Green Materials for Light Industry, School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Haoxiang Ni
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jialong Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qipeng Shi
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ran Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hongbo Yu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Mengjie Li
- College of Resources and Environment, Gansu Agricultural University, Lanzhou 730030, China.
| |
Collapse
|
37
|
Tailoring microbes to upgrade lignin. Curr Opin Chem Biol 2020; 59:23-29. [PMID: 32388219 DOI: 10.1016/j.cbpa.2020.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/16/2022]
Abstract
Lignin depolymerization generates a mixture of numerous compounds that are difficult to separate cost-effectively. To address this heterogeneity issue, microbes have been employed to 'biologically funnel' a broad range of compounds present in depolymerized lignin into common central metabolites that can be converted into a single desirable product. Because the composition of depolymerized lignin varies significantly with the type of biomass and the depolymerization method, microbes should be selected and engineered by considering this compositional variation. An ideal microbe must efficiently metabolize all relevant lignin-derived compounds regardless of the compositional variation of feedstocks, but discovering or developing such a perfect microbe is very challenging. Instead, developing multiple tailored microbes to tolerate a given mixture of lignin-derived compounds and to convert most of these into a target product is more practical. This review summarizes recent progress toward the development of such microbes for lignin valorization and offers future directions.
Collapse
|
38
|
Jiao S, Li F, Yu H, Shen Z. Advances in acrylamide bioproduction catalyzed with Rhodococcus cells harboring nitrile hydratase. Appl Microbiol Biotechnol 2019; 104:1001-1012. [DOI: 10.1007/s00253-019-10284-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/20/2019] [Accepted: 11/26/2019] [Indexed: 01/10/2023]
|
39
|
Roell GW, Carr RR, Campbell T, Shang Z, Henson WR, Czajka JJ, Martín HG, Zhang F, Foston M, Dantas G, Moon TS, Tang YJ. A concerted systems biology analysis of phenol metabolism in Rhodococcus opacus PD630. Metab Eng 2019; 55:120-130. [DOI: 10.1016/j.ymben.2019.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/19/2019] [Accepted: 06/30/2019] [Indexed: 01/28/2023]
|