Simultaneous Determination of Multiple Components in Nisin Fermentation Using FTIR Spectroscopy

Sivakesava Sakhamuri, Jamie Bober, Joseph Irudayaraj, Ali Demirci


The potential of noninvasive determination of glucose, lactic acid, and nisin in
Lactococcus lactis subsp. lactis biofilm fermentation was investigated through fourier
transform mid-infrared (FTIR) spectroscopy. Samples obtained from a biofilm bioreactor
were analyzed with traditional methods and FTIR spectroscopy. The FTIR spectra were
interpreted by using suitable spectra wavenumber regions through multivariate statistical
techniques such as partial least square (PLS) and principal component regression (PCR).
The standard error of calibration for the PLS-1st derivative calibration models for
glucose, lactic acid, and nisin were 3.87 g/l, 2.62 g/l, and 189.6 IU/ml, respectively.
Prediction errors were low for glucose and lactic acid, whereas nisin could be reliably
quantified when its concentration is higher than 800 IU/ml. Results indicated that FTIR
spectroscopy could be used for rapid detection of glucose and lactic acid concentrations,
and nisin activity in nisin fermentation.

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