Membrane-facilitated bioproduction of 3-methylcatechol in an octanol/water two-phase system

Hüsken, Leonie E.; Oomes, Mirjam; Schroën, Karin; Tramper, J.; Bont, J.A.M. de; Beeftink, Rik

doi:10.1016/s0168-1656(02)00045-7

Cited by 30 publications

(24 citation statements)

References 28 publications

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“…Since biomass and product formation are closely linked, a decreased Y x/s will translate directly into a lower Y p/s , which was underlined by the constant Y p/x of 13 C-mol% in both the aqueous and the biphasic watersolvent fed-batch cultivations. The decreased Y x/s caused by the extractant toxicity may be averted by the physical separation of the aqueous and organic phases by using advanced in situ product removal techniques such as solvent-impregnated resins (32) or membrane extraction (11). This, together with a stable genomic integration of the heterologous pal-pdc construct, would also lead to a more stable process.…”

Section: Discussionmentioning

confidence: 99%

Bioproduction of p -Hydroxystyrene from Glucose by the Solvent-Tolerant Bacterium Pseudomonas putida S12 in a Two-Phase Water-Decanol Fermentation

Verhoef

Wierckx

Westerhof

et al. 2009

Appl Environ Microbiol

128

127

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Two solvent-tolerant Pseudomonas putida S12 strains, originally designed for phenol and p-coumarate production, were engineered for efficient production of p-hydroxystyrene from glucose. This was established by introduction of the genes pal and pdc encoding L-phenylalanine/L-tyrosine ammonia lyase and p-coumaric acid decarboxylase, respectively. These enzymes allow the conversion of the central metabolite L-tyrosine into p-hydroxystyrene, via p-coumarate. Degradation of the p-coumarate intermediate was prevented by inactivating the fcs gene encoding feruloyl-coenzyme A synthetase. The best-performing strain was selected and cultivated in the fed-batch mode, resulting in the formation of 4.5 mM p-hydroxystyrene at a yield of 6.7% (C-mol of p-hydroxystyrene per C-mol of glucose) and a maximum volumetric productivity of 0.4 mM h ؊1 . At this concentration, growth and production were completely halted due to the toxicity of p-hydroxystyrene. Product toxicity was overcome by the application of a second phase of 1-decanol to extract p-hydroxystyrene during fed-batch cultivation. This resulted in a twofold increase of the maximum volumetric productivity (0.75 mM h ؊1 ) and a final total p-hydroxystyrene concentration of 21 mM, which is a fourfold improvement compared to the single-phase fed-batch cultivation. The final concentration of p-hydroxystyrene in the water phase was 1.2 mM, while a concentration of 147 mM (17.6 g liter ؊1 ) was obtained in the 1-decanol phase. Thus, a P. putida S12 strain producing the low-value compound phenol was successfully altered for the production of the toxic value-added compound p-hydroxystyrene.

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Section: Discussionmentioning

confidence: 99%

Bioproduction of p -Hydroxystyrene from Glucose by the Solvent-Tolerant Bacterium Pseudomonas putida S12 in a Two-Phase Water-Decanol Fermentation

Verhoef

Wierckx

Westerhof

et al. 2009

Appl Environ Microbiol

128

127

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“…To reduce the toxic effects of octanol Husken et al (2002b) implemented a hollow fiber membrane system and although the system experienced an increase in 3MC productivity to 173 mg/L-h difficulties such as solvent toxicity and mass transport still persisted. Further attempts to reduce the effects of solvent toxicity in biphasic system using aliphatic alcohols involve utilizing solvent tolerant microorganisms (Neumann et al, 2005;Rojas et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…A limitation associated with organic solvents is the potential toxicity that they may possess towards the biocatalyst. In order to minimize the toxic effects of a solvent, researchers have utilized solvent tolerant strains of bacteria (Faizal et al, 2005;Neumann et al, 2005;Wery et al, 2000;Wierckx et al, 2005), alternative bioreactor designs (Husken et al, 2002b) and have implemented intelligent solvent selection based on the octanol-water partitioning coefficient (log P) of solvents (Brink and Tramper, 1985;Bruce and Daugulis, 1991;Laane and Tramper, 1990). Of the techniques attempted to reduce solvent toxicity, rational solvent selection represents the most direct approach.…”

Section: Introductionmentioning

confidence: 99%

Solvent selection for enhanced bioproduction of 3‐methylcatechol in a two‐phase partitioning bioreactor

Prpich

Daugulis

2006

Biotech & Bioengineering

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The biotransformation of toluene to 3-methycatechol (3MC) via Pseudomonas putida MC2 was used as a model system for the development of a biphasic process offering enhanced overall volumetric productivity. Three factors were investigated for the identification of an appropriate organic solvent and they included solvent toxicity, bioavailability of the solvent as well as solvent affinity for 3MC. The critical log P (log P(crit)) of the biocatalyst was found to be 3.1 and log P values were used to predict a solvent's toxicity. The presence of various functional groups of candidate solvents were used to predict the absorption of 3MC and it was found that solvents possessing polarity showed an affinity towards 3MC. Bis (2-ethylhexyl) sebecate was selected for use in the biphasic system as it fulfilled all selection criteria. A two-phase biotransformation with BES and a 50% phase volume ratio, achieved an overall volumetric productivity of 440 mg 3MC/L-h, which was an improvement by a factor of approximately 4 over previously operated systems. Additional work focused on reducing the toluene feed in order to minimize possible toxicity and decrease loss of substrate (toluene), a result of volatilization. Toluene losses were reduced by a factor of 4, compared to previously operated systems, without suffering an appreciable loss in overall volumetric productivity.

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“…Previously [16], we studied a two-phase system without direct contact between octanol and the culture medium, by means of a membrane barrier. No lag time was found and more product accumulated in the aqueous phase, now that phase toxicity [17] was overcome.…”

Section: Comparison Of Processes With Different Phase Ratiosmentioning

confidence: 99%

Model description of bacterial 3-methylcatechol production in one- and two-phase systems

Silva

Malcata

2003

Bioprocess and Biosystems Engineering

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Pseudomonas putida MC2 produces 3-methylcatechol from toluene in aqueous medium. A second phase of 1-octanol may improve total product accumulation. To optimise the design of such a biphasic process, a process model was developed, both for one- and two-phase applications. The insights obtained by the model predictions showed the importance of different process parameters (like growth substrate concentration and partition coefficient) on growth of biomass, accumulation of 3-methylcatechol and processing time. For future applications, the process model can be used to ensure enough extraction capacity from aqueous to octanol phase. It is a useful tool to define the optimum process conditions, depending on the desired optimisation parameter: product concentration or processing time.

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Membrane-facilitated bioproduction of 3-methylcatechol in an octanol/water two-phase system

Cited by 30 publications

References 28 publications

Bioproduction of p -Hydroxystyrene from Glucose by the Solvent-Tolerant Bacterium Pseudomonas putida S12 in a Two-Phase Water-Decanol Fermentation

Bioproduction of p -Hydroxystyrene from Glucose by the Solvent-Tolerant Bacterium Pseudomonas putida S12 in a Two-Phase Water-Decanol Fermentation

Solvent selection for enhanced bioproduction of 3‐methylcatechol in a two‐phase partitioning bioreactor

Model description of bacterial 3-methylcatechol production in one- and two-phase systems

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