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Fu H, Lin M, Tang IC, Wang J, Yang ST. Effects of benzyl viologen on increasing NADH availability, acetate assimilation, and butyric acid production by Clostridium tyrobutyricum. Biotechnol Bioeng 2020; 118:770-783. [PMID: 33058166 DOI: 10.1002/bit.27602] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/18/2022]
Abstract
Clostridium tyrobutyricum produces butyric and acetic acids from glucose. The butyric acid yield and selectivity in the fermentation depend on NADH available for acetate reassimilation to butyric acid. In this study, benzyl viologen (BV), an artificial electron carrier that inhibits hydrogen production, was used to increase NADH availability and butyric acid production while eliminating acetic acid accumulation by facilitating its reassimilation. To better understand the mechanism of and find the optimum condition for BV effect on enhancing acetate assimilation and butyric acid production, BV at various concentrations and addition times during the fermentation were studied. Compared with the control without BV, the addition of 1 μM BV increased butyric acid production from glucose by ∼50% in yield and ∼29% in productivity while acetate production was completely inhibited. Furthermore, BV also increased the coutilization of glucose and exogenous acetate for butyric acid production. At a concentration ratio of acetate (g/L) to BV (mM) of 4, both acetate assimilation and butyrate biosynthesis increased with increasing the concentrations of BV (0-6.25 μM) and exogenous acetate (0-25 g/L). In a fed-batch fermentation with glucose and ∼15 g/L acetate and 3.75 μM BV, butyrate production reached 55.9 g/L with productivity 0.93 g/L/h, yield 0.48 g/g, and 97.4% purity, which would facilitate product purification and reduce production cost. Manipulating metabolic flux and redox balance via BV and acetate addition provided a simple to implement metabolic process engineering approach for butyric acid production from sugars and biomass hydrolysates.
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Affiliation(s)
- Hongxin Fu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Meng Lin
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - I-Ching Tang
- Bioprocessing Innovative Company, Dublin, Ohio, USA
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shang-Tian Yang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
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Fu H, Yang ST, Wang M, Wang J, Tang IC. Butyric acid production from lignocellulosic biomass hydrolysates by engineered Clostridium tyrobutyricum overexpressing xylose catabolism genes for glucose and xylose co-utilization. Bioresour Technol 2017; 234:389-396. [PMID: 28343058 DOI: 10.1016/j.biortech.2017.03.073] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 06/06/2023]
Abstract
Clostridium tyrobutyricum can utilize glucose and xylose as carbon source for butyric acid production. However, xylose catabolism is inhibited by glucose, hampering butyric acid production from lignocellulosic biomass hydrolysates containing both glucose and xylose. In this study, an engineered strain of C. tyrobutyricum Ct-pTBA overexpressing heterologous xylose catabolism genes (xylT, xylA, and xylB) was investigated for co-utilizing glucose and xylose present in hydrolysates of plant biomass, including soybean hull, corn fiber, wheat straw, rice straw, and sugarcane bagasse. Compared to the wild-type strain, Ct-pTBA showed higher xylose utilization without significant glucose catabolite repression, achieving near 100% utilization of glucose and xylose present in lignocellulosic biomass hydrolysates in bioreactor at pH 6. About 42.6g/L butyrate at a productivity of 0.56g/L·h and yield of 0.36g/g was obtained in batch fermentation, demonstrating the potential of C. tyrobutyricum Ct-pTBA for butyric acid production from lignocellulosic biomass hydrolysates.
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Affiliation(s)
- Hongxin Fu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China; Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - Shang-Tian Yang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA.
| | - Minqi Wang
- College of Animal Science, Zhejiang University, Hangzhou 310058, China
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - I-Ching Tang
- Bioprocessing Innovative Company, 4734 Bridle Path Ct., Dublin, OH 43017, USA
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Xue C, Liu F, Xu M, Tang IC, Zhao J, Bai F, Yang ST. Butanol production in acetone-butanol-ethanol fermentation with in situ product recovery by adsorption. Bioresour Technol 2016; 219:158-168. [PMID: 27484672 DOI: 10.1016/j.biortech.2016.07.111] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 06/06/2023]
Abstract
Activated carbon Norit ROW 0.8, zeolite CBV901, and polymeric resins Dowex Optipore L-493 and SD-2 with high specific loadings and partition coefficients were studied for n-butanol adsorption. Adsorption isotherms were found to follow Langmuir model, which can be used to estimate the amount of butanol adsorbed in acetone-butanol-ethanol (ABE) fermentation. In serum-bottle fermentation with in situ adsorption, activated carbon showed the best performance with 21.9g/L of butanol production. When operated in a fermentor, free- and immobilized-cell fermentations with adsorption produced 31.6g/L and 54.6g/L butanol with productivities of 0.30g/L·h and 0.45g/L·h, respectively. Thermal desorption produced a condensate containing ∼167g/L butanol, which resulted in a highly concentrated butanol solution of ∼640g/L after spontaneous phase separation. This in situ product recovery process with activated carbon is energy efficient and can be easily integrated with ABE fermentation for n-butanol production.
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Affiliation(s)
- Chuang Xue
- Department of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China; Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - Fangfang Liu
- Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - Mengmeng Xu
- Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - I-Ching Tang
- Bioprocessing Innovative Company, 4734 Bridle Path Court, Dublin, OH 43017, USA
| | - Jingbo Zhao
- Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - Fengwu Bai
- Department of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Shang-Tian Yang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA.
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Yu L, Xu M, Tang IC, Yang ST. Metabolic engineering of Clostridium tyrobutyricum for n-butanol production through co-utilization of glucose and xylose. Biotechnol Bioeng 2015; 112:2134-41. [PMID: 25894463 DOI: 10.1002/bit.25613] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 01/09/2023]
Abstract
The glucose-mediated carbon catabolite repression (CCR) in Clostridium tyrobutyricum impedes efficient utilization of xylose present in lignocellulosic biomass hydrolysates. In order to relieve the CCR and enhance xylose utilization, three genes (xylT, xylA, and xylB) encoding a xylose proton-symporter, a xylose isomerase and a xylulokinase, respectively, from Clostridium acetobutylicum ATCC 824 were co-overexpressed with aldehyde/alcohol dehydrogenase (adhE2) in C. tyrobutyricum (Δack). Compared to the strain Ct(Δack)-pM2 expressing only adhE2, the mutant Ct(Δack)-pTBA had a higher xylose uptake rate and was able to simultaneously consume glucose and xylose at comparable rates for butanol production. Ct(Δack)-pTBA produced more butanol (12.0 vs. 3.2 g/L) with a higher butanol yield (0.12 vs. 0.07 g/g) and productivity (0.17 vs. 0.07 g/L · h) from both glucose and xylose, while Ct(Δack)-pM2 consumed little xylose in the fermentation. The results confirmed that the CCR in C. tyrobutyricum could be overcome through overexpressing xylT, xylA, and xylB. The mutant was also able to co-utilize glucose and xylose present in soybean hull hydrolysate (SHH) for butanol production, achieving a high butanol titer of 15.7 g/L, butanol yield of 0.24 g/g, and productivity of 0.29 g/L · h. This study demonstrated the potential application of Ct(Δack)-pTBA for industrial biobutanol production from lignocellulosic biomass.
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Affiliation(s)
- Le Yu
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Ave., Columbus, Ohio, 43210
| | - Mengmeng Xu
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Ave., Columbus, Ohio, 43210
| | | | - Shang-Tian Yang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Ave., Columbus, Ohio, 43210.
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Yu L, Zhao J, Xu M, Dong J, Varghese S, Yu M, Tang IC, Yang ST. Metabolic engineering of Clostridium tyrobutyricum for n-butanol production: effects of CoA transferase. Appl Microbiol Biotechnol 2015; 99:4917-30. [DOI: 10.1007/s00253-015-6566-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 01/31/2023]
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Du Y, Jiang W, Yu M, Tang IC, Yang ST. Metabolic process engineering of Clostridium tyrobutyricum Δack-adhE2 for enhanced n-butanol production from glucose: effects of methyl viologen on NADH availability, flux distribution, and fermentation kinetics. Biotechnol Bioeng 2014; 112:705-15. [PMID: 25363722 DOI: 10.1002/bit.25489] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 01/28/2023]
Abstract
Butanol biosynthesis through aldehyde/alcohol dehydrogenase (adhE2) is usually limited by NADH availability, resulting in low butanol titer, yield, and productivity. To alleviate this limitation and improve n-butanol production by Clostridium tyrobutyricum Δack-adhE2 overexpressing adhE2, the NADH availability was increased by using methyl viologen (MV) as an artificial electron carrier to divert electrons from ferredoxin normally used for H2 production. In the batch fermentation with the addition of 500 μM MV, H2 , acetate, and butyrate production was reduced by more than 80-90%, while butanol production increased more than 40% to 14.5 g/L. Metabolic flux analysis revealed that butanol production increased in the fermentation with MV because of increased NADH availability as a result of reduced H2 production. Furthermore, continuous butanol production of ∼55 g/L with a high yield of ∼0.33 g/g glucose and extremely low ethanol, acetate, and butyrate production was obtained in fed-batch fermentation with gas stripping for in situ butanol recovery. This study demonstrated a stable and reliable process for high-yield and high-titer n-butanol production by metabolically engineered C. tyrobutyricum by applying MV as an electron carrier to increase butanol biosynthesis.
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Affiliation(s)
- Yinming Du
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 West 19th Avenue, Columbus, Ohio, 43210
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Yu M, Du Y, Jiang W, Chang WL, Yang ST, Tang IC. Effects of different replicons in conjugative plasmids on transformation efficiency, plasmid stability, gene expression and n-butanol biosynthesis in Clostridium tyrobutyricum. Appl Microbiol Biotechnol 2011; 93:881-9. [DOI: 10.1007/s00253-011-3736-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 10/29/2011] [Accepted: 11/15/2011] [Indexed: 11/30/2022]
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Yu M, Zhang Y, Tang IC, Yang ST. Metabolic engineering of Clostridium tyrobutyricum for n-butanol production. Metab Eng 2011; 13:373-82. [DOI: 10.1016/j.ymben.2011.04.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/23/2011] [Accepted: 04/14/2011] [Indexed: 10/18/2022]
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Abstract
Clostridium formicoaceticum homofermentatively converted lactate to acetate at mesophilic temperatures (30 to 42 degrees C) and at pHs between 6.6 and 9.6. The production of acetate was found to be growth associated. Approximately 0.96 g of acetic acid and 0.066 g of cells were formed from each gram of lactic acid consumed at 37 degrees C. The concentration of the substrate (lactate) had little or no effect on the growth rate; however, the fermentation was inhibited by acetic acid. The bacterium grew at an optimal pH of 7.6 and an optimal temperature of 37 degrees C. Small amounts of bicarbonate were stimulatory to bacterial growth. Bacterial growth was enhanced, however, by the use of higher concentrations of bicarbonate in the media, only because higher buffer capacities were obtained and proper medium pH could be maintained for growth. Based on its ability to convert lactate to acetate, this homoacetic bacterium may be important in the anaerobic methanogenic process when lactate is a major intermediary metabolite.
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Affiliation(s)
- S T Yang
- Department of Chemical Engineering, The Ohio State University, Columbus, Ohio 43210, and Department of Agricultural Engineering, Purdue University, West Lafayette, Indiana 47907
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Abstract
Clostridium formicoaceticum homofermentatively converts lactate to acetate at 37 degrees C and pH 6.6-9.6. However, this fermentation is strongly inhibited by acetic acid at acidic pH. The specific growth rate of this organism decreased from a maximum at pH 7.6 to zero at pH 6.6. This inhibition effect was found to be attributed to both H(+) and undissociated acetic acid. At pH values below 7.6, the H(+) inhibited the fermentation following non-competitive inhibition kinetics. The acetic acid inhibition was found to be stronger at a lower medium pH. At pH 6.45-6.8, cell growth was found to be primarily limited by a maximum undissociated acetic acid concentration of 0.358 g/L (6mM). This indicates that the undissociated acid, not the dissociated acid, is the major acid inhibitor. At pH 7.6 or higher, this organism could tolerate acetate concentrations of higher than 0.8M, but salt (Na(+)) became a strong inhibitor at concentrations of higher than 0.4M. Acetic acid inhibition also can be represented by noncompetitive inhibition kinetics. A mathematical model for this homoacetic fermentation was also developed. This model can be used to simulate batch fermentation at any pH between 6.9 and 7.6.
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Affiliation(s)
- I C Tang
- Department of Agricultural Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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Bai Y, Koh CG, Boreman M, Juang YJ, Tang IC, Lee LJ, Yang ST. Surface modification for enhancing antibody binding on polymer-based microfluidic device for enzyme-linked immunosorbent assay. Langmuir 2006; 22:9458-67. [PMID: 17042569 DOI: 10.1021/la061123l] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A novel surface treatment method using poly(ethyleneimine) (PEI), an amine-bearing polymer, was developed to enhance antibody binding on the poly(methyl methacrylate) (PMMA) microfluidic immunoassay device. By treating the PMMA surface of the microchannel on the microfluidic device with PEI, 10 times more active antibodies can be bound to the microchannel surface as compared to those without treatment or treated with the small amine-bearing molecule, hexamethylenediamine (HMD). Consequently, PEI surface modification greatly improved the immunoassay performance of the microfluidic device, making it more sensitive and reliable in the detection of IgG. The improvement can be attributed to the spacer effect as well as the functional amine groups provided by the polymeric PEI molecules. Due to the smaller dimensions (140x125 microm) of the microchannel, the time required for antibody diffusion and adsorption onto the microchannel surface was reduced to only several minutes, which was 10 times faster than the similar process carried out in 96-well plates. The microchip also had a wider detection dynamic range, from 5 to 1000 ng/mL, as compared to that of the microtiter plate (from 2 to 100 ng/mL). With the PEI surface modification, PMMA-based microchips can be effectively used for enzyme linked immunosorbent assays (ELISA) with a similar detection limit, but much less reagent consumption and shorter assay time as compared to the conventional 96-well plate.
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Affiliation(s)
- Yunling Bai
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, USA
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Yang ST, Tang IC. Methanogenesis from lactate by a co-culture of Clostridium formicoaceticum and Methanosarcina mazei. Appl Microbiol Biotechnol 1991. [DOI: 10.1007/bf00180648] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Affiliation(s)
- S T Yang
- Department of Chemical Engineering, Ohio State University, Columbus 43210
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Tang IC, Yang ST, Okos MR. Acetic acid production from whey lactose by the co-culture ofStreptococcus lactis andClostridium formicoaceticum. Appl Microbiol Biotechnol 1988. [DOI: 10.1007/bf00694301] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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