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Branska B, Koppova K, Husakova M, Patakova P. Application of fed-batch strategy to fully eliminate the negative effect of lignocellulose-derived inhibitors in ABE fermentation. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:87. [PMID: 38915101 PMCID: PMC11197323 DOI: 10.1186/s13068-024-02520-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/16/2024] [Indexed: 06/26/2024]
Abstract
BACKGROUND Inhibitors that are released from lignocellulose biomass during its treatment represent one of the major bottlenecks hindering its massive utilization in the biotechnological production of chemicals. This study demonstrates that negative effect of inhibitors can be mitigated by proper feeding strategy. Both, crude undetoxified lignocellulose hydrolysate and complex medium supplemented with corresponding inhibitors were tested in acetone-butanol-ethanol (ABE) fermentation using Clostridium beijerinckii NRRL B-598 as the producer strain. RESULTS First, it was found that the sensitivity of C. beijerinckii to inhibitors varied with different growth stages, being the most significant during the early acidogenic phase and less pronounced during late acidogenesis and early solventogenesis. Thus, a fed-batch regime with three feeding schemes was tested for toxic hydrolysate (no growth in batch mode was observed). The best results were obtained when the feeding of an otherwise toxic hydrolysate was initiated close to the metabolic switch, resulting in stable and high ABE production. Complete utilization of glucose, and up to 88% of xylose, were obtained. The most abundant inhibitors present in the alkaline wheat straw hydrolysate were ferulic and coumaric acids; both phenolic acids were efficiently detoxified by the intrinsic metabolic activity of clostridia during the early stages of cultivation as well as during the feeding period, thus preventing their accumulation. Finally, the best feeding strategy was verified using a TYA culture medium supplemented with both inhibitors, resulting in 500% increase in butanol titer over control batch cultivation in which inhibitors were added prior to inoculation. CONCLUSION Properly timed sequential feeding effectively prevented acid-crash and enabled utilization of otherwise toxic substrate. This study unequivocally demonstrates that an appropriate biotechnological process control strategy can fully eliminate the negative effects of lignocellulose-derived inhibitors.
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Affiliation(s)
- Barbora Branska
- Department of Biotechnology, University of Chemistry and Technology Prague, Technická 5, 16628, Prague, Czech Republic.
| | - Kamila Koppova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technická 5, 16628, Prague, Czech Republic
| | - Marketa Husakova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technická 5, 16628, Prague, Czech Republic
| | - Petra Patakova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technická 5, 16628, Prague, Czech Republic
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Kumar S, Agyeman-Duah E, Ujor VC. Whole-Genome Sequence and Fermentation Characteristics of Enterobacter hormaechei UW0SKVC1: A Promising Candidate for Detoxification of Lignocellulosic Biomass Hydrolysates and Production of Value-Added Chemicals. Bioengineering (Basel) 2023; 10:1090. [PMID: 37760192 PMCID: PMC10525534 DOI: 10.3390/bioengineering10091090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/11/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Enterobacter hormaechei is part of the Enterobacter cloacae complex (ECC), which is widespread in nature. It is a facultative Gram-negative bacterium of medical and industrial importance. We assessed the metabolic and genetic repertoires of a new Enterobacter isolate. Here, we report the whole-genome sequence of a furfural- and 5-hydroxymethyl furfural (HMF)-tolerant strain of E. hormaechei (UW0SKVC1), which uses glucose, glycerol, xylose, lactose and arabinose as sole carbon sources. This strain exhibits high tolerance to furfural (IC50 = 34.2 mM; ~3.3 g/L) relative to Escherichia coli DH5α (IC50 = 26.0 mM; ~2.5 g/L). Furfural and HMF are predominantly converted to their less-toxic alcohols. E. hormaechei UW0SKVC1 produces 2,3-butanediol, acetoin, and acetol, among other compounds of industrial importance. E. hormaechei UW0SKVC1 produces as high as ~42 g/L 2,3-butanediol on 60 g/L glucose or lactose. The assembled genome consists of a 4,833,490-bp chromosome, with a GC content of 55.35%. Annotation of the assembled genome revealed 4586 coding sequences and 4516 protein-coding genes (average length 937-bp) involved in central metabolism, energy generation, biodegradation of xenobiotic compounds, production of assorted organic compounds, and drug resistance. E. hormaechei UW0SKVC1 shows considerable promise as a biocatalyst and a genetic repository of genes whose protein products may be harnessed for the efficient bioconversion of lignocellulosic biomass, abundant glycerol and lactose-replete whey permeate to value-added chemicals.
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Affiliation(s)
| | | | - Victor C. Ujor
- Metabolic Engineering and Fermentation Science Group, Department of Food Science, University of Wisconsin-Madison, Babcock Hall, 1605 Linden Drive, Madison, WI 53706, USA; (S.K.); (E.A.-D.)
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Ujor VC, Okonkwo CC. Microbial detoxification of lignocellulosic biomass hydrolysates: Biochemical and molecular aspects, challenges, exploits and future perspectives. Front Bioeng Biotechnol 2022; 10:1061667. [PMID: 36483774 PMCID: PMC9723337 DOI: 10.3389/fbioe.2022.1061667] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 10/31/2022] [Indexed: 08/26/2023] Open
Abstract
Valorization of lignocellulosic biomass (LB) has the potential to secure sustainable energy production without impacting food insecurity, whist relieving over reliance on finite fossil fuels. Agro-derived lignocellulosic residues such as wheat straw, switchgrass, rice bran, and miscanthus have gained relevance as feedstocks for the production of biofuels and chemicals. However, the microorganisms employed in fermentative conversion of carbohydrates to fuels and chemicals are unable to efficiently utilize the sugars derived from LB due to co-production of lignocellulose-derived microbial inhibitory compounds (LDMICs) during LB pretreatment. LDMICs impact microbial growth by inhibition of specific enzymes, cause DNA and cell membrane damage, and elicit cellular redox imbalance. Over the past decade, success has been achieved with the removal of LDMICs prior to fermentation. However, LDMICs removal by chemical processes is often accompanied by sugar losses, which negatively impacts the overall production cost. Hence, in situ removal of LDMICs by fermentative organisms during the fermentation process has garnered considerable attention as the "go-to" approach for economical LDMICs detoxification and bio-chemicals production. In situ removal of LDMICs has been pursued by either engineering more robust biocatalysts or isolating novel microbial strains with the inherent capacity to mineralize or detoxify LDMICs to less toxic compounds. While some success has been made along this line, efficient detoxification and robust production of target bio-chemicals in lignocellulosic hydrolysates (LHs) under largely anaerobic fermentative conditions remains a lingering challenge. Consequently, LB remains an underutilized substrate for bio-chemicals production. In this review, the impact of microbial LH detoxification on overall target molecule production is discussed. Further, the biochemical pathways and mechanisms employed for in situ microbial detoxification of furanic LDMICs [e.g., furfural and 5-hydroxymethylfurfural (HMF)] and phenolic LDMICs (e.g., syringaldehyde, p-coumaric acid, 4-hydroxybenzaldehyde, vanillin, and ferulic acid) are discussed. More importantly, metabolic engineering strategies for the development of LDMIC-tolerant and bio-chemicals overproducing strains and processes are highlighted.
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Affiliation(s)
- Victor C. Ujor
- Metabolic Engineering and Fermentation Science Group, Department of Food Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Christopher C. Okonkwo
- Biotechnology Program, College of Science, The Roux Institute, Northeastern University, Portland, ME, United States
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Mechanistic modeling of redox balance effects on the fermentation of eucalyptus wood-derived xylose to acetone-butanol-ethanol. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Olorunsogbon T, Adesanya Y, Atiyeh HK, Okonkwo CC, Ujor VC, Ezeji TC. Effects of Clostridium beijerinckii and Medium Modifications on Acetone–Butanol–Ethanol Production From Switchgrass. Front Bioeng Biotechnol 2022; 10:942701. [PMID: 35992339 PMCID: PMC9382077 DOI: 10.3389/fbioe.2022.942701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2022] Open
Abstract
The presence of lignocellulose-derived microbial inhibitory compounds (LDMICs) in lignocellulosic biomass (LB) hydrolysates is a barrier to efficient conversion of LB hydrolysates to fuels and chemicals by fermenting microorganisms. Results from this study provide convincing evidence regarding the effectiveness of metabolically engineered C. beijerinckii NCIMB 8052 for the fermentation of LB-derived hydrolysates to acetone–butanol–ethanol (ABE). The engineered microbial strain (C. beijerinckii_SDR) was produced by the integration of an additional copy of a short-chain dehydrogenase/reductase (SDR) gene (Cbei_3904) into the chromosome of C. beijerinckii NCIMB 8052 wildtype, where it is controlled by the constitutive thiolase promoter. The C. beijerinckii_SDR and C. beijerinckii NCIMB 8052 wildtype were used for comparative fermentation of non-detoxified and detoxified hydrothermolysis-pretreated switchgrass hydrolysates (SHs) with and without (NH4)2CO3 supplementation. In the absence of (NH4)2CO3, fermentation of non-detoxified SH with C. beijerinckii_SDR resulted in the production of 3.13- and 2.25-fold greater quantities of butanol (11.21 g/L) and total ABE (20.24 g/L), respectively, than the 3.58 g/L butanol and 8.98 g/L ABE produced by C. beijerinckii_wildtype. When the non-detoxified SH was supplemented with (NH4)2CO3, concentrations were similar for butanol (9.5 compared with 9.2 g/L) and ABE (14.2 compared with 13.5 g/L) produced by C. beijerinckii_SDR and C. beijerinckii_wildtype, respectively. Furthermore, when C. beijerinckii_SDR and C. beijerinckii_wildtype were cultured in detoxified SH medium, C. beijerinckii_SDR produced 1.11- and 1.18-fold greater quantities of butanol and ABE, respectively, than when there was culturing with C. beijerinckii_wildtype. When the combined results of the present study are considered, conclusions are that the microbial strain and medium modifications of the fermentation milieu resulted in greater production of fuels and chemicals from non-detoxified LB hydrolysates.
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Affiliation(s)
- Tinuola Olorunsogbon
- Department of Animal Science, The Ohio State University, Wooster, OH, United States
| | - Yinka Adesanya
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, United States
| | - Hasan K. Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, United States
| | - Christopher Chukwudi Okonkwo
- Biotechnology Program, College of Science, The Roux Institute, Northeastern University, Portland, ME, United States
| | - Victor Chinomso Ujor
- Department of Food Science, University of Wisconsin-Madison, Maddison, WI, United States
| | - Thaddeus Chukwuemeka Ezeji
- Department of Animal Science, The Ohio State University, Wooster, OH, United States
- *Correspondence: Thaddeus Chukwuemeka Ezeji,
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Adesanya Y, Atiyeh HK, Olorunsogbon T, Khanal A, Okonkwo CC, Ujor VC, Shah A, Ezeji TC. Viable strategies for enhancing acetone-butanol-ethanol production from non-detoxified switchgrass hydrolysates. BIORESOURCE TECHNOLOGY 2022; 344:126167. [PMID: 34678446 DOI: 10.1016/j.biortech.2021.126167] [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: 08/30/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
A process engineering strategy was investigated towards developing a viable scheme for effective conversion of hydrothermolysis pretreated non-detoxified switchgrass hydrolysates (SH) to acetone butanol ethanol (ABE) using a metabolically engineered strain of Clostridium beijerinckii NCIMB 8052, C. beijerinckii_AKR. The engineered strain was modified by homologous integration into the chromosome and constitutive expression of Cbei_3974, which encodes an aldo-keto reductase. Intermittent feeding strategy was employed in which fermentation was initiated with 30% of the SH and the remaining 70% SH was added when the optical density (OD600nm) of C. beijerinckii attained 0.5. The ABE (14.9 g/L) produced from non-detoxified SH by the inhibitor-tolerant C. beijerinckii_AKR was comparable to the P2-glucose control medium (14.7 g/L). Using intermittent feeding, wildtype and C. beijerinckii_AKR produced similar amounts of ABE (about 17.5 g/L). This shows that intermittent feeding strategy and C. beijerinckii_AKR enhanced ABE fermentation and eliminated the need for SH detoxification prior to fermentation.
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Affiliation(s)
- Yinka Adesanya
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hasan K Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA.
| | - Tinuola Olorunsogbon
- Department of Animal Science, The Ohio State University, and Ohio State Agricultural Research and Development Center, Wooster, OH, USA
| | - Asmita Khanal
- Department of Food, Agricultural and Biological Engineering, The Ohio State University, Wooster, OH, USA
| | - Christopher C Okonkwo
- Department of Animal Science, The Ohio State University, and Ohio State Agricultural Research and Development Center, Wooster, OH, USA
| | - Victor C Ujor
- Department of Food Science, University of Wisconsin-Madison, Maddison, WI, USA
| | - Ajay Shah
- Department of Food, Agricultural and Biological Engineering, The Ohio State University, Wooster, OH, USA
| | - Thaddeus C Ezeji
- Department of Animal Science, The Ohio State University, and Ohio State Agricultural Research and Development Center, Wooster, OH, USA
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Patakova P, Branska B, Vasylkivska M, Jureckova K, Musilova J, Provaznik I, Sedlar K. Transcriptomic studies of solventogenic clostridia, Clostridium acetobutylicum and Clostridium beijerinckii. Biotechnol Adv 2021; 58:107889. [PMID: 34929313 DOI: 10.1016/j.biotechadv.2021.107889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 12/13/2022]
Abstract
Solventogenic clostridia are not a strictly defined group within the genus Clostridium but its representatives share some common features, i.e. they are anaerobic, non-pathogenic, non-toxinogenic and endospore forming bacteria. Their main metabolite is typically 1-butanol but depending on species and culture conditions, they can form other metabolites such as acetone, isopropanol, ethanol, butyric, lactic and acetic acids, and hydrogen. Although these organisms were previously used for the industrial production of solvents, they later fell into disuse, being replaced by more efficient chemical production. A return to a more biological production of solvents therefore requires a thorough understanding of clostridial metabolism. Transcriptome analysis, which reflects the involvement of individual genes in all cellular processes within a population, at any given (sampling) moment, is a valuable tool for gaining a deeper insight into clostridial life. In this review, we describe techniques to study transcription, summarize the evolution of these techniques and compare methods for data processing and visualization of solventogenic clostridia, particularly the species Clostridium acetobutylicum and Clostridium beijerinckii. Individual approaches for evaluating transcriptomic data are compared and their contributions to advancements in the field are assessed. Moreover, utilization of transcriptomic data for reconstruction of computational clostridial metabolic models is considered and particular models are described. Transcriptional changes in glucose transport, central carbon metabolism, the sporulation cycle, butanol and butyrate stress responses, the influence of lignocellulose-derived inhibitors on growth and solvent production, and other respective topics, are addressed and common trends are highlighted.
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Affiliation(s)
- Petra Patakova
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic.
| | - Barbora Branska
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic
| | - Maryna Vasylkivska
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic
| | | | - Jana Musilova
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
| | - Ivo Provaznik
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
| | - Karel Sedlar
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
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8
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Joseph RC, Kelley SQ, Kim NM, Sandoval NR. Metabolic Engineering and the Synthetic Biology Toolbox for
Clostridium. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Chacón SJ, Matias G, Ezeji TC, Maciel Filho R, Mariano AP. Three-stage repeated-batch immobilized cell fermentation to produce butanol from non-detoxified sugarcane bagasse hemicellulose hydrolysates. BIORESOURCE TECHNOLOGY 2021; 321:124504. [PMID: 33307480 DOI: 10.1016/j.biortech.2020.124504] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
To enable the production of butanol with undiluted, non-detoxified sugarcane bagasse hemicellulose hydrolysates, this study developed a three-staged repeated-batch immobilized cell fermentation in which the efficiency of a 3D-printed nylon carrier to passively immobilize Clostridium saccharoperbutylacetonicum DSM 14923 was compared with sugarcane bagasse. The first stage consisted of sugarcane molasses fermentation, and in the second stage, non-detoxified sugarcane bagasse hemicellulose hydrolysates (SBHH) was pulse-fed to sugarcane molasses fermentation. In the next four batches, immobilized cells were fed with undiluted SBHH supplemented with molasses, and SBHH-derived xylose accounted for approximately 50% of the sugars. Bagasse was a superior carrier, and the average xylose utilization (33%) was significantly higher than the treatment with the 3D-printed carrier (16%). Notably, bagasse allowed for 43% of the butanol to be SBHH-derived. Overall, cell immobilization on lignocellulosic materials can be an efficient strategy to produce butanol from repeated-batch fermentation of non-detoxified hemicellulose hydrolysates.
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Affiliation(s)
- Suranny Jiménez Chacón
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Gabriela Matias
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Thaddeus Chukwuemeka Ezeji
- The Ohio State University, Department of Animal Sciences, Ohio State Agricultural Research and Development Center, Wooster, OH, USA
| | - Rubens Maciel Filho
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Adriano Pinto Mariano
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Ma R, Su P, Jin B, Guo J, Tian M, Mao L, Tang J, Chen T, Lai C, Zeng W, Cui G, Huang L. Molecular cloning and functional identification of a high-efficiency (+)-borneol dehydrogenase from Cinnamomum camphora (L.) Presl. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 158:363-371. [PMID: 33243711 DOI: 10.1016/j.plaphy.2020.11.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/16/2020] [Indexed: 06/11/2023]
Abstract
Cinnamomum camphora (L.) Presl, rich in terpenoids, is an important commercial plant. The monoterpenes borneol and camphor are highly desired compounds that have been widely and diversely used in medicine and spices since ancient times. However, the key enzymes in the biosynthetic pathway of borneol and camphor in C. camphora remains unknown, which limits access to these natural products. Here, the chirality of borneol and camphor were identified in C. camphora leaves. Besides the main (+)-borneol and (+)-camphor, C. camphora also contains small amounts of (-)-borneol and (-)-camphor. Then, CcBDH3 - an efficient (+)-borneol dehydrogenase (BDH) - was identified that catalyzed (+)-borneol into (+)-camphor in the presence of NAD+. The Km value was 25.1 μM with a kcat value of 5.4 × 10-3 s-1 at pH 8.5 and 30 °C. CcBDH3, which also yields (-)-camphor from (-)-borneol as a substrate, had a Km value of 36.9 μM with a kcat of 2.1 × 10-3 s-1, and pH of 8.0 and temperature of 32 °C. We further compared the conformational specificity of two other reported BDHs, ZSD1 and ADH2, and found that ZSD1 had the highest conversion rate with (-)-borneol. These findings provide a new way for the production of camphor with various optical activities by metabolic engineering, and the identified camphor biosynthesis pathway provides the foundation for using genetic engineering to improve the production and purity of (+)-borneol in planta.
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Affiliation(s)
- Rui Ma
- School of Pharmacy, Henan University of Chinese Medicine, No. 156 Jinshuidong Road, Zhengzhou, 450008, China; State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Ping Su
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China; Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, United States.
| | - Baolong Jin
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Juan Guo
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Mei Tian
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Liuying Mao
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Jinfu Tang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Tong Chen
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Changjiangsheng Lai
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Wen Zeng
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Guanghong Cui
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
| | - Luqi Huang
- School of Pharmacy, Henan University of Chinese Medicine, No. 156 Jinshuidong Road, Zhengzhou, 450008, China; State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16 South Side Street, Dongzhimen, Beijing, 100700, China.
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Okonkwo CC, Ujor V, Cornish K, Ezeji TC. Inactivation of the Levansucrase Gene in Paenibacillus polymyxa DSM 365 Diminishes Exopolysaccharide Biosynthesis during 2,3-Butanediol Fermentation. Appl Environ Microbiol 2020; 86:e00196-20. [PMID: 32144108 PMCID: PMC7170477 DOI: 10.1128/aem.00196-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/27/2020] [Indexed: 11/20/2022] Open
Abstract
The formation of exopolysaccharides (EPSs) during 2,3-butanediol (2,3-BD) fermentation by Paenibacillus polymyxa increases medium viscosity, which in turn presents considerable technical and economic challenges to 2,3-BD downstream processing. To eliminate EPS production during 2,3-BD fermentation, we used homologous recombination to disable the EPS biosynthetic pathway in P. polymyxa The gene which encodes levansucrase, the major enzyme responsible for EPS biosynthesis in P. polymyxa, was successfully disrupted. The P. polymyxa levansucrase null mutant produced 2.5 ± 0.1 and 1.2 ± 0.2 g/liter EPS on sucrose and glucose, respectively, whereas the wild type produced 21.7 ± 2.5 and 3.1 ± 0.0 g/liter EPS on the same substrates, respectively. These levels of EPS translate to 8.7- and 2.6-fold decreases in EPS formation by the levansucrase null mutant on sucrose and glucose, respectively, relative to that by the wild type, with no significant reduction in 2,3-BD production. Inactivation of EPS biosynthesis led to a considerable increase in growth. On glucose and sucrose, the cell biomass of the levansucrase null mutant (8.1 ± 0.8 and 6.5 ± 0.3 g/liter, respectively) increased 1.4-fold compared to that of the wild type (6.0 ± 0.1 and 4.6 ± 0.3 g/liter, respectively) grown on the same substrates. Evaluation of the genetic stability of the levansucrase null mutant showed that it remained genetically stable over fifty generations, with no observable decrease in growth or 2,3-BD formation, with or without antibiotic supplementation. Hence, the P. polymyxa levansucrase null mutant has potential for use as an industrial biocatalyst for a cost-effective large-scale 2,3-BD fermentation process devoid of EPS-related challenges.IMPORTANCE Given the current barrage of attention and research investments toward the production of next-generation fuels and chemicals, of which 2,3-butanediol (2,3-BD) produced by nonpathogenic Paenibacillus species is perhaps one of the most vigorously pursued, tools for engineering Paenibacillus species are intensely sought after. Exopolysaccharide (EPS) production during 2,3-BD fermentation constitutes a problem during downstream processing. Specifically, EPS negatively impacts 2,3-BD separation from the fermentation broth, thereby increasing the overall cost of 2,3-BD production. The results presented here demonstrate that inactivation of the levansucrase gene in P. polymyxa leads to diminished EPS accumulation. Additionally, a new method for an EPS assay and a simple protocol employing protoplasts for enhanced transformation of P. polymyxa were developed. Overall, although our study shows that levan is not the only EPS produced by P. polymyxa, it represents a significant first step toward developing cost-effective 2,3-BD fermentation devoid of EPS-associated complications during downstream processing.
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Affiliation(s)
- Christopher Chukwudi Okonkwo
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
| | - Victor Ujor
- Bioenergy and Water Treatment Management Program, Agricultural Technical Institute, The Ohio State University, Wooster, Ohio, USA
| | - Katrina Cornish
- Department of Food, Agricultural and Biological Engineering, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
- Department of Horticulture and Crop Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
| | - Thaddeus Chukwuemeka Ezeji
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio, USA
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Sun X, Atiyeh HK, Adesanya Y, Okonkwo C, Zhang H, Huhnke RL, Ezeji T. Feasibility of using biochar as buffer and mineral nutrients replacement for acetone-butanol-ethanol production from non-detoxified switchgrass hydrolysate. BIORESOURCE TECHNOLOGY 2020; 298:122569. [PMID: 31862676 DOI: 10.1016/j.biortech.2019.122569] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 05/22/2023]
Abstract
Biochar can be an inexpensive pH buffer and source of mineral and trace metal nutrients in acetone-butanol-ethanol (ABE) fermentation. This study evaluated the feasibility of replacing expensive 4-morpholineethanesulfonic acid (MES) P2 buffer and mineral nutrients with biochar made from switchgrass (SGBC), forage sorghum (FSBC), redcedar (RCBC) and poultry litter (PLBC) for ABE fermentation. Fermentations using Clostridium beijerinckii ATCC 51743 in glucose and non-detoxified switchgrass hydrolysate media were performed at 35 °C in 250 mL bottles for 72 h. Medium containing buffer and minerals without biochar was the control. Similar ABE production (about 18.0 g/L) in glucose media with SGBC, FSBC and RCBC and control was measured. However in non-detoxified switchgrass hydrolysate medium, SGBC, RCBC and PLBC produced more ABE (about 18.5 g/L) than the control (10.1 g/L). This demonstrates that biochar is an effective buffer and mineral supplement for ABE production from lignocellulosic biomass without costly detoxification process.
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Affiliation(s)
- Xiao Sun
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hasan K Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA.
| | - Yinka Adesanya
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Christopher Okonkwo
- Department of Animal Science, The Ohio State University, and Ohio State Agricultural Research and Development Center, Wooster, OH, USA
| | - Hailin Zhang
- Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Raymond L Huhnke
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Thaddeus Ezeji
- Department of Animal Science, The Ohio State University, and Ohio State Agricultural Research and Development Center, Wooster, OH, USA
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