Fig. 2.

[1]H-NMR spectrum of 3-hydroxybutyrate (P3HB) produced by Burkholderia contaminans LTEB11. (1) The multiplet at 5.25 ppm corresponds to 1H (a) in the asymmetric carbon; (2) The doublet of the quadruplet at 2.35 ppm corresponds to 2H (b) in the methylene group adjacent to an asymmetric carbon atom. PHB samples (10 mg) were dissolved in CDCl₃ and subjected to analysis. ¹H-NMR spectra were acquired for each sample at 600 MHz using an AscendTM 600 spectrometer (Bruker) equipped with a 5-mm QXI inverse probe and a sample case autosampler. PHB accumulation assays were performed according to Matias et al. [28]. Flask cultures containing 500 mL of liquid ISP9 medium (2% (w/v) of glucose) were incubated in a shaker at 30 °C for 72 h, 120 rpm. Culture samples were harvested by centrifugation, lyophilized, and pretreated with two acetone baths and treated with chloroform at 60 °C for 48 h under agitation. After the treatment, the contents of flasks were filtered through Whatman no. 1 filter paper and dried at room temperature until PHB film formation