title: Assessment of in-line near-infrared spectroscopy for continuous monitoring of fermentation processes.
abstract: The application of NIR in-line to monitor and control fermentation processes was investigated. Determination of biomass, glucose, and lactic and acetic acids during fermentations of Staphylococcus xylosus ES13 was performed by an interactance fiber optic probe immersed into the culture broth and connected to a NIR instrument. Partial least squares regression (PLSR) calibration models of second derivative NIR spectra in the 700-1800 nm region gave satisfactory predictive models for all parameters of interest: biomass, glucose, and lactic and acetic acids. Batch, repeated batch, and continuous fermentations were monitored and automatically controlled by interfacing the NIR to the bioreactor control unit. The high frequency of data collection permitted an accurate study of the kinetics, supplying lots of data that describe the cultural broth composition and strengthen statistical analysis. Comparison of spectra collected throughout fermentation runs of S. xylosus ES13, Lactobacillus fermentum ES15, and Streptococcus thermophylus ES17 demonstrated the successful extension of a unique calibration model, developed for S. xylosus ES13, to other strains that were differently shaped but growing in the same medium and fermentation conditions. NIR in-line was so versatile as to measure several biochemical parameters of different bacteria by means of slightly adapted models, avoiding a separate calibration for each strain.
authors.affiliation: Chemistry Department, University of Ferrara, Via L. Borsari, 46, 44100 Ferrara, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Tosi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
authors.forename: Elena
authors.initials: E
authors.lastname: Tamburini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vaccari
authors.forename: Alberto
authors.initials: A
authors.lastname: Amaretti
authors.forename: Diego
authors.initials: D
authors.lastname: Matteuzzi
mesh_terms: D019342:Acetic Acid / Q000032:analysis*; D019149:Bioreactors / Q000382:microbiology; D002138:Calibration; D002452:Cell Count / Q000379:methods*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002455:Cell Division / Q000502:physiology; D005285:Fermentation / Q000502:physiology; D005336:Fiber Optic Technology / Q000295:instrumentation; D005947:Glucose / Q000032:analysis*; D019344:Lactic Acid / Q000032:analysis*; D007778:Lactobacillus / Q000166:cytology / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D009862:Online Systems; D055100:Optical Fibers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods*; D013210:Staphylococcus / Q000166:cytology / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism*; D013291:Streptococcus / Q000166:cytology / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D019344:Lactic Acid; D005947:Glucose; D019342:Acetic Acid