Tensor 27

High resolution Transmission Electron Microscopy (HR-TEM) images were obtained on JEOL JEM-2100 (electron microscope operating at 200 kV, Jeol JEM-2100F, Tokyo, Japan). Particle sizes were obtained from DLS (Nanotrac Wave) and FT-IR data recorded on Bruker Tensor27 FT-IR (DTGS detector and KBR beam splitter, Bruker, Vertex 80v and Tensor 27, Billerica, MA, USA). UV-visible absorption spectra obtained from JASCO V-570 UV-vis spectrophotometer (JASCO, Tokyo, Japan) and Photoluminescence emission spectra was recorded on fluorescence spectrometer (FLS920, equipped with a 450 W broadband Xe lamp, Edinburgh). In vitro cellular viabilities measured by using Infinite 200 (TECAN, Männedorf, Switzerland). Fluorescence images of cancer cells were recorded using a confocal laser scanning microscope (CLSM; Leica, TCS SP5X, LSM 700, Zeiss, Jena, Germany) equipped with an InGaN semiconductor laser (405 nm), an Ar laser (488 nm), and a He–Ne laser (533 nm), respectively.

Crude extracted PHA was analyzed for conformity with Fourier-transform infrared spectroscopy (FTIR) using a Bruker Tensor 27 (Bruker Corp., Billerica, MA, USA) equipped with an attenuated total reflection unit (ATR). Interferograms were taken between 550 and 4000 cm⁻¹. Samples were scanned 30 times at a 4 cm⁻¹ resolution. The resulting pattern of functional groups were compared to the PHB standard.

The contents of cellulose, hemicellulose and lignin in the samples before and after pretreatment were calculated by following the National Renewable Energy Laboratory (NREL) method as described in Sluiter et al. [21 ]. The surface morphology of pretreated and enzyme-hydrolyzed samples was imaged using NanoSEM 490 SEM (FEI.Co, USA) with an accelerating voltage of 15 kV at magnifications of 1000 [22 (link)]. The crystalline phases of pretreated and hydrolyzed straws were characterized by X-ray diffractogram (XRD, Bruker D5005, Karlsruhe, Germany). The samples were scanned from 10° to 40° with a step size of 0.05° and the crystallinity index (CrI) was determined by following “Segal” method (Eq. 1) as described in Segal et al. [23 (link)]. $$\text{CrI}\left(\%\right)=\left(I_{002}-I_{\text{am}}\right)/I_{002}\times 100\%,$$ where I₀₀₂ is the highest peak intensity at 2θ = 22° and I_am is the intensity of amorphous portion at 2θ = 18°.
In addition, the FTIR spectrometer (Bruker Tensor 27, Germany) was used for revealing the changes of the functional groups in pretreated and hydrolyzed straws. Samples were prepared by grinding with KBr at a ratio of 1:100 (w/w) and pressing into pellets. The spectra were recorded within a range of 400–4000 cm⁻¹ with a resolution of 4 cm⁻¹ and 32 scans per sample [24 (link)].

Infrared spectrometry was used as one of the structure verification methods, but itwas mainly supposed to serve as a confirmation of –OH hydroxyl functional groups in alkyl esters of either lactic acid or 3-hydroxybutanoic acid. Analyses were performed on the infrared spectrometer Bruker Tensor 27 (Billerica, MA, USA) by the attenuated total reflectance (ATR) method using diamond as a dispersion component. The irradiation source in this type of spectrometer is a diode laser. Due to the fact that instrumentation uses Fourier transformation, the Michelson interferometer was used for the quantification of the signal. Spectra were composed out of 32 total scans with a measurement resolution of 2 cm⁻¹.

The interaction of DMP/DnBP with each facet was identified on an IR spectrometer with a liquid-nitrogen-cooled mercury cadmium telluride detector (Bruker Tensor 27, Bruker, Germany). The acetone-based DMP or DnBP was inoculated into each hematite (20 μmol g⁻¹), then the mixture was ground and prepared into KBr wafer (1%, wt. %) for measurement. In addition, by DRIFTS measurement, each hematite nanoparticles were filled into an HVC-DRP-5 accessory (Harrick Scientific, USA). DMP was carried by a N₂ flow (15 mL min⁻¹) in combination with a second channel of the humidified N₂ flow (90 ml L⁻¹, RH 76%) to pass through the hematite powder. As gaseous DMP was adsorbed by the hematite nanoparticles, its IR signal was recorded in situ as a function of time. The DRITFS system was operated at 25 °C. To indicate the surface Lewis-acid site distribution, the same DRIFTS method was applied using Cl-DMA as the probe molecule. This method was described in our previous study^{12 (link)}.