A new way of quantifying the production of poly(hydroxyalkanoate)s using FTIR

Abstract

BACKGROUND Conventional techniques used for determination of extractable poly(hydroxyalkanoate)s (PHAs) present in cells are laborious and destructive. Fourier transform infrared (FTIR) spectroscopy is an indirect analytical method to study molecular structures and has been used for the detection and quantification of PHA in intact cells. However, obtain a fine powder with pure PHA to prepare KBr pellets is a difficult task. The objective of this study was to develop a cheap alternative for quantifying the extractable intracellular PHA, based on a pulverizable solid as a standard material (PEM: Pre Extraction Material) produced by Bacillus megaterium BBST4 strain, instead of pure PHA produced by the same strain. Through statistical analysis the correlation between sample content and its FTIR spectra were determined. The proposed methodology employs typical MID-FTIR equipment and KBr pellets for spectra determination. RESULTS Small root-mean-standard errors of prediction of the amount of extractable PHA were obtained using partial least square regression (PLSR1). In order to simplify the determination process, a simple linear regression analysis (SLRA) was also developed, and satisfactory correlations were found. CONCLUSIONS Results from PLSR1 and SLRA, calibrated with the proposed standard, indicate that it is a simple, fast and reliable alternative of fitting for determining the extractable PHA in unknown lyophilized cell samples. © 2015 Society of Chemical Industry