title: Comparing in situ removal strategies for improving styrene bioproduction.
abstract: As an important conventional monomer compound, the biological production of styrene carries significant promise with respect to creating novel sustainable materials. Since end-product toxicity presently limits styrene production by previously engineered Escherichia coli, in situ product removal by both solvent extraction and gas stripping were explored as process-based strategies for circumventing its inhibitory effects. In solvent extraction, the addition of bis(2-ethylhexyl)phthalate offered the greatest productivity enhancement, allowing net volumetric production of 836 ± 64 mg/L to be reached, representing a 320 % improvement over single-phase cultures. Gas stripping rates, meanwhile, were controlled by rates of bioreactor agitation and, to a greater extent, aeration. A periodic gas stripping protocol ultimately enabled up to 561 ± 15 mg/L styrene to be attained. Lastly, by relieving the effects of styrene toxicity, new insight was gained regarding subsequent factors limiting its biosynthesis in E. coli and strategies for future strain improvement are discussed.
authors.affiliation: Department of Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, PO Box 876106, Tempe, AZ, 85287-6106, USA.
authors.forename: Rebekah
authors.initials: R
authors.lastname: McKenna
authors.forename: Luis
authors.initials: L
authors.lastname: Moya
authors.forename: Matthew
authors.initials: M
authors.lastname: McDaniel
authors.forename: David R
authors.initials: DR
authors.lastname: Nielsen
mesh_terms: D019149:Bioreactors; D004051:Diethylhexyl Phthalate / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D020058:Styrene / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D020058:Styrene; D004051:Diethylhexyl Phthalate