title: Potential of on-line CIMS for bioprocess monitoring.
abstract: Chemical-ionization mass spectrometry (CIMS) using flow reactors is an emerging method for on-line monitoring of trace concentrations of organic compounds in the gas phase. In this study, a flow-reactor CIMS instrument, employing the H(3)O(+) cation as the ionizing reagent, was used to simultaneously monitor several volatile metabolic products as they are released into the headspace during bacterial growth in a bioreactor. Production of acetaldehyde, ethanol, acetone, butanol, acetoin, diacetyl, and isoprene by Bacillus subtilis is reported. Ion signal intensities were related to solution-phase concentrations using empirical calibrations and, in the case of isoprene, were compared with simultaneous gas chromatography measurements. Identification of volatile and semivolatile metabolites is discussed. Flow-reactor CIMS techniques should be useful for bioprocess monitoring applications because of their ability to sensitively and simultaneously monitor many volatile metabolites on-line.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder Colorado 80309-0215, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Custer
authors.forename: William P
authors.initials: WP
authors.lastname: Wagner
authors.forename: Shuji
authors.initials: S
authors.lastname: Kato
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Bierbaum
authors.forename: Ray
authors.initials: R
authors.lastname: Fall
mesh_terms: D000093:Acetoin / Q000378:metabolism*; D001412:Bacillus subtilis / Q000254:growth & development* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D002070:Butadienes / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods; D045782:Hemiterpenes / Q000378:metabolism*; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods; D009862:Online Systems; D010420:Pentanes / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D000093:Acetoin