Two phase partitioning bioreactors

Malinowski, J.J. (2001) Two-phase partitioning bioreactors in fermentation technology. Biotechnology Advances, 19, 525-538. 

In biphasic reactors or two-phase partitioning bioreactors (TPPB), the substrate is located mostly in the immiscible phase and diffuses to the aqueous phase. The enzyme catalyzes conversion of the substrate at the interface and/or in the aqueous phase. The product/s of the reaction then may partition to the organic phase. The system is self-regulated, as the substrate delivery to the aqueous phase is only directed by the partitioning ratio between the two phases and the enzymatic reaction rate [53]. The use of ionic liquid/supercritical carbon dioxide for enzyme-catalyzed transformation is gaining attention [69]. 

Eibes G, Moreira MT, Feijoo G et al (2007) Operation of a two-phase partitioning bioreactor for the oxidation of anthracene by the enzyme manganese peroxidase. Chemosphere 66 1744-1751... 

As a basic in B LMs for the wastewater treatment the author presents two-phase partitioning bioreactors. He presents the main criteria which must be considered in the selection of the LM solvent biocompatibility (toxicity of the solvent to the microorganism), bioavailabihty (resistance of the solvent to biodegradation by the microorganism used), immiscibility in the aqueous phase, high solubility of pollutant in the solvent, favorable mass-transfer characteristics, etc. Biodegradation mechanisms and kinetics are discussed. Apphcations of bioreactors in wastewater treatment in laboratory, phot, and industrial scale are reviewed. Potential applications are considered also. 

Many anthropogenic organic compounds are highly hydrophobic in character, that is, they possess high values of the 1-octanol/water partitioning coefficient (generally expressed as the log P). They can be present in different types of wastewaters. In such context, the two-phase partitioning bioreactors can be used for the elimination of these compounds from wastewater. They... 

Figure 8.1 The two-phase partitioning bioreactor (for more information see [7]).

The solvent should be readily available from a local supplier and be cost-effective for pilot- and/or industrial scale [7]. The solubility of the pollutant in question in the diluent should be as high as possible to allow maximum pollutant loadings in the two-phase partitioning bioreactor system, that is, make the biodegradation system perform most effectively [1]. As the last criterion, the diluent should not form emulsion with the treated wastewater. This is required to minimize the entrainment of the cells of the MO used in the organic phase of the system, potentially leading to decrease in the rate of biodegradation [12]. 

The value of PDiiuent/feed phase determines the equilibrium concentrations of the pollutant in the LM, and the treated wastewater based on its definition in Eq. (1). The higher the Ppiiuent/feed phase value, the higher the loading of the pollutant that can be dosed into the two-phase partitioning bioreactor system, based on the higher solubility of the pollutant in the LM. At the same time, however, the lower the rate of diffusion from the LM into the feed phase, thus the longer the time required for the elimination of the... 

The fifth criterion is the volatility ofthe diluent. It needs to be taken into account because volatile diluents can cause losses of the pollutant from the two-phase partitioning bioreactor without proper biodegradation, due to stripping of the diluent in the aeration stream [7]. It has been suggested that nonvolatile solvents have the boiling points above 150 °C [38]. The last two criteria are the price and the availability of the chosen diluent from a local supplier. These two criteria are important because of the feasibility and... 

CoUins and Dauguhs [46] used industrial grade oleyl alcohol as the diluent in a two-phase partitioning bioreactor. This was inoculated with Pseudomonas sp. ATCC 55595, and the authors studied the biodegradation ofbenzene, toluene, and p-xylene, individuaUy and in different mixtures. The authors compared the efficiency of the aromatic hydrocarbon removal in the batch mode and the fed-batch mode. In a mixture of benzene and... 

Enrichment cultures have been reported to fail during biodegradation of certain substrates [3]. Application of the two-phase partitioning bioreactor can help shorten the acclimation period and can also lead to faster removal of higher loadings of the pollutant in question [3]. Enrichment can also be successful in contrast with one-phase systems (see below). Several mechanisms of pollutant uptake exist in the two-phase partitioning bioreactor. These are direct uptake of the molecules dissolved in the feed phase [43], and/or uptake of the dissolved molecule but the MO increases... 

To date and to the best of the author s knowledge, only one commercial application has been reported for two-phase partitioning bioreactors. It is based on the work by the research group of Prof. Andrew S. Daugulis from the Queen s University in Kingston, Canada [58], which has been licensed to Xethanol Corporation [59]. 

Daugulis, A. J. (2001). Two-phase partitioning bioreactors A new technology platform for destroying xenobiotics Trends in Biotechnology 19 457-462. 

MacLeod, C. T., Daugulis, A. J. (2003). Biodegradation of polycyclic aromatic hydrocarbons in a two-phase partitioning bioreactor in the presence of a bioavailable solvent. Applied Microbiology and Biotechnology 62 291-296. 

Yeom, S. H., Daugulis, A.J. (2001). Benzene degradation in a two-phase partitioning bioreactor by Alcaligenes xylosoxidans Y234. Process Biochemistry 36 765-772. 

Munoz, R., Guieysee, B., Mattiasson, B. (2003). Phenanthrene biodegration by an algal-bacterial consortium in two-phase partitioning bioreactors. Applied Microbiology and Biotechnology 61 261-267. 

Guieysse, B., Autem, Y., Soares, A. (2005). Biodegradation of phenol at low temperature using two-phase partitioning bioreactors. Water Science and Technology 52 97-105. 

Cruickshank, S. M., Daugulis, A. J., McLellan, P.J. (2000). Dynamic modeling and optimal fed-batch feeding strategies for a two-phase partitioning bioreactor. Biotechnology and Bioengineering 67 224-233. 

Zilouei, H., Guieysse, B., Mattiasson, B. (2008). Two-phase partitioning bioreactor for the biodegradation of high concentrations of pentachlorophenol using Sphingobium chlorophenolicum DSM 8671. Chemosphere 72 1788-1794. 

MacLeod, C. T., Dauguhs, A. (2005). Interfacial effects in a two-phase partitioning bioreactor Degradation of polycyclic hydrocarbons (PAHs) by a hydrophobic Mycobacterium. Process Biochemistry 40 1799-1805. 

Munoz R, Rolvering C, Guieysse B, Mattiasson B. (2005). Aerobic phenanthrene biodegradation in a two-phase partitioning bioreactor. Water Science and Technology 52 265-271. 

Pudge IB, Daugulis AJ, and Dubois CT, The use of Enterobacter cloacae ATCC 43560 in the development of a two-phase partitioning bioreactor for the destruction of hexa-hydro-l,3,5-trinitro-l,3,5-triazine (RDX), J. Biotechnol., 100, 65, 2003. 

The application of two phase partitioning bioreactors (TPPBs) presents some difficult biochemical engineering challenges including the selection of an appropriate... 

Newman JD, Marshall J, Keasling JD et al (2006) High-level production of amorpha-4, 11 -diene in a two phase partitioning bioreactor of metabolically engineered Escherichia coli. Biotechnol Bioeng 95 684-691... 

The introduction of in situ product removal by adsorption on hydrophobic resin greatly improved the yields of some of these processes. For instance, production with Streptomyces sp. V-1 has been increased to 19.5 gl simply by addition of a macroporous adsorbent resin [47], and the production with Amycolatopsis sp. ATCC 39116 has been pushed to 19.5gl in a solid-liquid two-phase partitioning bioreactor [48]. These are the highest values of productivity achieved at present. 

Benzyl alcohol has also been employed as substrate with the methylotrophic yeast Pichia pastoris, in the presence of methanol, that induces the production of nonspecific alcohol oxidases able to convert benzyl alcohol to benzaldehyde. Very recently, in situ product removal approaches (adsorption and/or pervaporation) have been exploited with this system. In particular, adsorption on hydrophobic resin in a solid-liquid two-phase partitioning bioreactor afforded yields of up to 14g in a 5-1 reactor [104,105]. 

Ma, X. and Daugulis, A.J. (2014) Transformation of ferulic acid to vanillin using a fed-batch solid-liquid two-phase partitioning bioreactor. Biotechnol. Progr., 30, 207—214. 

A.J. (2010) Bioproduction of benzaldehyde in a solid-liquid two-phase partitioning bioreactor using Pichia pastoris. Biotechnol. Lett, 31, 1649-1654. 

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