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Jiang T, Zhang C, He Q, Zheng Z, Ouyang J. Metabolic Engineering of Escherichia coli K12 for Homofermentative Production of L-Lactate from Xylose. Appl Biochem Biotechnol 2018; 184:703-715. [PMID: 28840503 DOI: 10.1007/s12010-017-2581-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
Abstract
The efficient utilization of xylose is regarded as a technical barrier to the commercial production of bulk chemicals from biomass. Due to the desirable mechanical properties of polylactic acid (PLA) depending on the isomeric composition of lactate, biotechnological production of lactate with high optical pure has been increasingly focused in recent years. The main objective of this work was to construct an engineered Escherichia coli for the optically pure L-lactate production from xylose. Six chromosomal deletions (pflB, ldhA, ackA, pta, frdA, adhE) and a chromosomal integration of L-lactate dehydrogenase-encoding gene (ldhL) from Bacillus coagulans was involved in construction of E. coli KSJ316. The recombinant strain could produce L-lactate from xylose resulting in a yield of 0.91 g/g xylose. The chemical purity of L-lactate was 95.52%, and the optical purity was greater than 99%. Moreover, three strategies, including overexpression of L-lactate dehydrogenase, intensification of xylose catabolism, and addition of additives to medium, were designed to enhance the production. The results showed that they could increase the concentration of L-lactate by 32.90, 20.13, and 233.88% relative to the control, respectively. This was the first report that adding formate not only could increase the xylose utilization but also led to the fewer by-product levels.
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Affiliation(s)
- Ting Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing, 210037, People's Republic of China.,College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Chen Zhang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Qin He
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing, 210037, People's Republic of China.,College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Zhaojuan Zheng
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing, 210037, People's Republic of China.,College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Jia Ouyang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing, 210037, People's Republic of China. .,College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China. .,Key Laboratory of Forest Genetics and Biotechnology of the Ministry of Education, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.
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Metabolic impact of increased NADH availability in Saccharomyces cerevisiae. Appl Environ Microbiol 2009; 76:851-9. [PMID: 20023106 DOI: 10.1128/aem.02040-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Engineering the level of metabolic cofactors to manipulate metabolic flux is emerging as an attractive strategy for bioprocess applications. We present the metabolic consequences of increasing NADH in the cytosol and the mitochondria of Saccharomyces cerevisiae. In a strain that was disabled in formate metabolism, we either overexpressed the native NAD(+)-dependent formate dehydrogenase in the cytosol or directed it into the mitochondria by fusing it with the mitochondrial signal sequence encoded by the CYB2 gene. Upon exposure to formate, the mutant strains readily consumed formate and induced fermentative metabolism even under conditions of glucose derepression. Cytosolic overexpression of formate dehydrogenase resulted in the production of glycerol, while when this enzyme was directed into the mitochondria, we observed glycerol and ethanol production. Clearly, these results point toward different patterns of compartmental regulation of redox homeostasis. When pulsed with formate, S. cerevisiae cells growing in a steady state on glucose immediately consumed formate. However, formate consumption ceased after 20 min. Our analysis revealed that metabolites at key branch points of metabolic pathways were affected the most by the genetic perturbations and that the intracellular concentrations of sugar phosphates were specifically affected by time. In conclusion, the results have implications for the design of metabolic networks in yeast for industrial applications.
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Hoffmann D, Müller RH. 2,4-Dichlorophenoxyacetic Acid (2,4-D) Utilization by Delftia acidovorans MC1 at Alkaline pH and in the Presence of Dichlorprop is Improved by Introduction of the tfdK Gene. Biodegradation 2006; 17:263-73. [PMID: 16715405 DOI: 10.1007/s10532-005-6894-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2005] [Indexed: 11/29/2022]
Abstract
Growth of Delftia acidovorans MC1 on 2,4-dichlorophenoxyacetic acid (2,4-D) and on racemic 2-(2,4-dichlorophenoxy)propanoic acid ((RS)-2,4-DP) was studied in the perspective of an extension of the strain's degradation capacity at alkaline pH. At pH 6.8 the strain grew on 2,4-D at a maximum rate (mu max) of 0.158 h(-1). The half-maximum rate-associated substrate concentration (Ks) was 45 microM. At pH 8.5 mu max was only 0.05 h(-1) and the substrate affinity was mucher lower than at pH 6.8. The initial attack of 2,4-D was not the limiting step at pH 8.5 as was seen from high dioxygenase activity in cells grown at this pH. High stationary 2,4-D concentrations and the fact that mu max with dichlorprop was around 0.2 h(-1) at both pHs rather pointed at limited 2,4-D uptake at pH 8.5. Introduction of tfdK from D. acidovorans P4a by conjugation, coding for a 2,4-D-specific transporter resulted in improved growth on 2,4-D at pH 8.5 with mu max of 0.147 h(-1) and Ks of 267 microM. Experiments with labeled substrates showed significantly enhanced 2,4-D uptake by the transconjugant TK62. This is taken as an indication of expression of the tfdK gene and proper function of the transporter. The uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) reduced the influx of 2,4-D. At a concentration of 195 microM 2,4-D, the effect amounted to 90% and 50%, respectively, with TK62 and MC1. Cloning of tfdK also improved the utilization of 2,4-D in the presence of (RS)-2,4-DP. Simultaneous and almost complete degradation of both compounds occurred in TK62 up to D = 0.23 h(-1) at pH 6.8 and up to D = 0.2 h(-1) at pH 8.5. In contrast, MC1 left 2,4-D largely unutilized even at low dilution rates when growing on herbicide mixtures at pH 8.5.
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Affiliation(s)
- Doreen Hoffmann
- Department for Environmental Microbiology, UFZ Centre for Environmental Research, Permoserstr. 15, D-04318, Leipzig, Germany
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Babel W, Brinkmann U, Müller RH. The auxiliary substrate concept - an approach for overcoming limits of microbial performances. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370130302] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Müller RH, Babel W. Energy and reducing equivalent potential of C2-compounds for microbial growth. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370080314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Müler RH, Babel W, Uhlenhut GJ. Simultaneous utilization of methanol and glucose by Hansenula polymorpha (Torulopsis sp.) MH 26, a chemostatic investigation on the distribution of14C-methanol. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370080405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Müller RH, Babel W. Dinitrophenol influences the rate and yield ofAcetobacter methanolicusduring the growth on glucose. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370130303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Müller RH, Babel W. Low energy gain from formate oxidation during bacterial growth on 2,4-dichlorophenoxyacetic acid. J Basic Microbiol 1996. [DOI: 10.1002/jobm.3620360208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
The stoichiometric limit to the biomass yield (maximal assimilation of the carbon source) is determined by the amount of CO2 lost in anabolism and the amount of carbon source required for generation of NADPH. This stoichiometric limit may be reached when yeasts utilize formate as an additional energy source. Factors affecting the biomass yield on single substrates are discussed under the following headings: Energy requirement for biomass formation (YATP). YATP depends strongly on the nature of the carbon source. Cell composition. The macroscopic composition of the biomass, and in particular the protein content, has a considerable effect on the ATP requirement for biomass formation. Hence, determination of for instance the protein content of biomass is relevant in studies on bioenergetics. Transport of the carbon source. Active (i.e. energy-requiring) transport, which occurs for a number of sugars and polyols, may contribute significantly to the calculated theoretical ATP requirement for biomass formation. P/O-ratio. The efficiency of mitochondrial energy generation has a strong effect on the cell yield. The P/O-ratio is determined to a major extent by the number of proton-translocating sites in the mitochondrial respiratory chain. Maintenance and environmental factors. Factors such as osmotic stress, heavy metals, oxygen and carbon dioxide pressures, temperature and pH affect the yield of yeasts. Various mechanisms may be involved, often affecting the maintenance energy requirement. Metabolites such as ethanol and weak acids. Ethanol increases the permeability of the plasma membrane, whereas weak acids can act as proton conductors. Energy content of the growth substrate. It has often been attempted in the literature to predict the biomass yield by correlating the energy content of the carbon source (represented by the degree of reduction) to the biomass yield or the percentage assimilation of the carbon source. An analysis of biomass yields of Candida utilis on a large number of carbon sources indicates that the biomass yield is mainly determined by the biochemical pathways leading to biomass formation, rather than by the energy content of the substrate.
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Affiliation(s)
- C Verduyn
- Department of Microbiology and Enzymology, Kluyver Laboratory of Biotechnology, Delft University of Technology, The Netherlands
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Müller RH, Babel W. Emulsifier formation with Acinetobacter: search for an excretion-reduced mutant of Acinetobacter calcoaceticus 69-V. J Basic Microbiol 1986; 26:181-4. [PMID: 3746629 DOI: 10.1002/jobm.3620260311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
After growth on acetate three groups of Acinetobacter strains could be identified with respect to the excretion of a bioemulsifier. Mutants of A. calcoaceticus 69-V were selected which produced reduced amounts of emulsifier.
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