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Zabed HM, Akter S, Rupani PF, Akor J, Zhang Y, Zhao M, Zhang C, Ragauskas AJ, Qi X. Biocatalytic gateway to convert glycerol into 3-hydroxypropionic acid in waste-based biorefineries: Fundamentals, limitations, and potential research strategies. Biotechnol Adv 2023; 62:108075. [PMID: 36502965 DOI: 10.1016/j.biotechadv.2022.108075] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/02/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022]
Abstract
Microbial conversion of bioenergy-derived waste glycerol into value-added chemicals has emerged as an important bioprocessing technology due to its eco-friendliness, feasible technoeconomics, and potential to provide sustainability in biodiesel and bioethanol production. Glycerol is an abundant liquid waste from bioenergy plants with a projected volume of 6 million tons by 2025, accounting for about 10% of biodiesel and 2.5% of bioethanol yields. 3-Hydroxypropionic acid (3-HP) is a major product of glycerol bioconversion, which is the third largest biobased platform compound with expected market size and value of 3.6 million tons/year and USD 10 billion/year, respectively. Despite these biorefinery values, 3-HP biosynthesis from glycerol is still at an immature stage of commercial exploitation. The main challenges behind this immaturity are the toxic effects of 3-HPA on cells, the distribution of carbon flux to undesirable pathways, low tolerance of cells to glycerol and 3-HP, co-factor dependence of enzymes, low enzyme activity and stability, and the problems of substrate inhibition and specificity of enzymes. To address these challenges, it is necessary to understand the fundamentals of glycerol bioconversion and 3-HP production in terms of metabolic pathways, related enzymes, cell factories, midstream process configurations, and downstream 3-HP recovery, as discussed in this review critically and comprehensively. It is equally important to know the current challenges and limitations in 3-HP production, which are discussed in detail along with recent research efforts and remaining gaps. Finally, possible research strategies are outlined considering the recent technological advances in microbial biosynthesis, aiming to attract further research efforts to achieve a sustainable and industrially exploitable 3-HP production technology. By discussing the use of advanced tools and strategies to overcome the existing challenges in 3-HP biosynthesis, this review will attract researchers from many other similar biosynthesis technologies and provide a common gateway for their further development.
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Affiliation(s)
- Hossain M Zabed
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Suely Akter
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Parveen Fatemah Rupani
- Department of Chemical Engineering, Ku Luven, Jan De Nayerlaan 5, 2860 Sint-Katelijne-Waver, Belgium
| | - Joseph Akor
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Yufei Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Mei Zhao
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Cunsheng Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA; UTK-ORNL Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Xianghui Qi
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China; School of Life Sciences, Guangzhou University, Guangzhou 510,006, Guangdong Province, China.
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Shibata N, Higuchi Y, Kräutler B, Toraya T. Structural Insights into the Very Low Activity of the Homocoenzyme B 12 Adenosylmethylcobalamin in Coenzyme B 12 -Dependent Diol Dehydratase and Ethanolamine Ammonia-Lyase. Chemistry 2022; 28:e202202196. [PMID: 35974426 DOI: 10.1002/chem.202202196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Indexed: 11/11/2022]
Abstract
The X-ray structures of coenzyme B12 (AdoCbl)-dependent eliminating isomerases complexed with adenosylmethylcobalamin (AdoMeCbl) have been determined. As judged from geometries, the Co-C bond in diol dehydratase (DD) is not activated even in the presence of substrate. In ethanolamine ammonia-lyase (EAL), the bond is elongated in the absence of substrate; in the presence of substrate, the complex likely exists in both pre- and post-homolysis states. The impacts of incorporating an extra CH2 group are different in the two enzymes: the DD active site is flexible, and AdoMeCbl binding causes large conformational changes that make DD unable to adopt the catalytic state, whereas the EAL active site is rigid, and AdoMeCbl binding does not induce significant conformational changes. Such flexibility and rigidity of the active sites might reflect the tightness of adenine binding. The structures provide good insights into the basis of the very low activity of AdoMeCbl in these enzymes.
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Affiliation(s)
- Naoki Shibata
- Department of Life Science, Graduate School of Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
| | - Yoshiki Higuchi
- Department of Life Science, Graduate School of Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
| | - Bernhard Kräutler
- Institute of Organic Chemistry and, Center of Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| | - Tetsuo Toraya
- Department of Bioscience and Biotechnology, Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka, Okayama, 700-8530, Japan
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Jäger C, Croft AK. If It Is Hard, It Is Worth Doing: Engineering Radical Enzymes from Anaerobes. Biochemistry 2022; 62:241-252. [PMID: 36121716 PMCID: PMC9850924 DOI: 10.1021/acs.biochem.2c00376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
With a pressing need for sustainable chemistries, radical enzymes from anaerobes offer a shortcut for many chemical transformations and deliver highly sought-after functionalizations such as late-stage C-H functionalization, C-C bond formation, and carbon-skeleton rearrangements, among others. The challenges in handling these oxygen-sensitive enzymes are reflected in their limited industrial exploitation, despite what they may deliver. With an influx of structures and mechanistic understanding, the scope for designed radical enzymes to deliver wanted processes becomes ever closer. Combined with new advances in computational methods and workflows for these complex systems, the outlook for an increased use of radical enzymes in future processes is exciting.
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