Assessment of near-infrared spectral information for rapid monitoring of bioprocess quality

Access to real-time process information is desirable for consistent and eff icient operation of bioprocesses. Near-infrared spectroscopy (NIRS) is know n to have potential for providing real-time information on the quantitative levels of important bioprocess variables. However, given the fact that a t ypical NIR spectrum encompasses information regarding almost all the consti tuents of the sample matrix, there are few case studies that have investiga ted the spectral details for applications in bioprocess quality assessment or qualitative bioprocess monitoring. Such information would be invaluable in providing operator-level assistance on the progress of a bioprocess in i ndustrial-scale productions. We investigated this aspect and report the res ults of our investigation. Near-infrared spectral information derived from scanning unprocessed culture fluid (broth) samples from a complex antibioti c production process was assessed for a data set that incorporated bioproce ss variations. Principal component analysis was applied to the spectral dat a and the loadings and scores of the principal components studied. Changes in the spectral information that corresponded to variations in the bioproce ss could be deciphered. Despite the complexity of the matrix, near-infrared spectra of the culture broth are shown to have valuable information that c an be deconvoluted with the help of factor analysis techniques such as prin cipal component analysis (PCA). Although complex to interpret, the loadings and score plots are shown to offer potential in process diagnosis that cou ld be of value in the rapid assessment of process quality, and in data asse ssment prior to quantitative model development. (C) 2001 John Wiley & Sons, Inc.