title: Auxiliary phase guidelines for microbial biotransformations of toxic substrate into toxic product.
abstract: When an industrial process is developed using the microbial transformation of a precursor into a desired chemical compound, high concentrations of substrate and product will be involved. These compounds may become toxic to the cells. In situ product removal (ISPR) may be carried out, using auxiliary phases such as extractants or adsorbents. Simultaneously, in situ substrate addition (ISSA) may be performed. It is shown that for uncharged substrates and products, the aqueous solubilities of substrate and product can be used to predict if ISPR might be required. When a particular auxiliary phase is selected and the distribution coefficients of substrate and product are known, it is possible to estimate a priori if this auxiliary phase might be good enough and how much of it might be needed for an efficient (fed-)batch biotransformation process. For biotransformation products of intermediate polarity (aqueous solubility of about 1-10 g/L) there seems to be a lack of extractants and adsorbents with the capacity to raise the product concentrations to commercially more interesting levels.
authors.affiliation: Kluyver Laboratory for Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands. straathof@tnw.tudelft.nl
authors.forename: A J J
authors.initials: AJ
authors.lastname: Straathof
mesh_terms: D000465:Algorithms; D018407:Bacterial Physiological Phenomena / Q000187:drug effects*; D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division / Q000187:drug effects* / Q000502:physiology*; D003198:Computer Simulation; D017408:Guidelines as Topic; D007218:Industrial Microbiology / Q000379:methods*; D008954:Models, Biological; D044367:Phase Transition; D011786:Quality Control; D014867:Water / Q000737:chemistry / Q000378:metabolism
chemical_list: D001688:Biological Products; D014867:Water