Nano zsp

NanoLPGs were diluted in water and analyzed in terms of their physical properties by dynamic light scattering (DLS) using a Malvern Instruments NanoZSP (Worcestershire, UK). The measured parameters were hydrodynamic diameter (HD), the polydispersity index (PdI) and the zeta potential (ZP). All assays were performed using a disposable folded capillary cell (Malvern, Panalytical, Worcestershire, UK), with a 90° laser angle and at room temperature (25 °C).

Samples for dynamic light scattering (DLS) were prepared by diluting KaPOx to 1.0 mg ml⁻¹ in 50 mM Tris-HCl and 100 mM NaCl (pH 8.5). Subsequently, the soluble protein solution was filtered through a 0.22-μm filter and centrifuged at 20,000 × g for 5 min to remove remaining aggregates. Supernatants were analyzed in a Zetasizer Nano ZSP autotitrator system (Malvern) at 633 nm, and with back scattering at an angle of 173°. Size distribution models were fitted based on data obtained from 10-s integrations of the sample (Mark-Houwink parameters: A = 0.428 and k = 7.67 × 10⁻⁵ cm² s⁻¹) with data processing optimized for protein sample by the supplier’s software. Measurements of POx from T. ochracaea and cellobiose dehydrogenase from Myceliophthora thermophilaserved as standards. Analysis of the pH-dependent aggregation of KaPOx was realized via pH titration with 0.5 M HCl from pH 9.0 to 5.0.

The oil-in-water (oil/water) emulsion was used as feed to evaluate the magnitude of the membrane fouling control provided by the rotary spacer system. The feed sample was prepared by mixing a crude oil (obtained from one of the crude oil wells in Malaysia) in deionized water with a small amount of synthesis-grade sodium dodecyl sulfate (SDS 98, Sigma Aldrich, St. Louis, MO, USA) with a ratio of 1:9 (wt./wt.) of SDS to the crude oil. The mixture with a total volume of 10 L was stirred for two days until a stable emulsion was obtained. The added SDS acted as a surfactant to stabilize the oil-in-water emulsion. The oil concentration in the feed was fixed at 1000 ppm. A small volume of feed sample (10 mL) was subsequently analyzed using particle size and zeta potential analyzer (Malvern, Zetasizer Nano ZSP, Malvern, UK) to map the distribution of the oil droplets. The droplet size was analysed using the dynamic light scattering method by assuming all the detected particles were the oil-in-water droplets in spherical shapes.

The particle size and poly-dispersity index (PDI) of NA-Sp-Rv-1200 nanocomposite films were assessed using a Zeta-sizer (Nano ZSP, Malvern Instrument, Worcestershire, UK). The film was reconstituted in distilled water (Refractive index is 1.33) before measurements. The zeta-potential evaluation was done with disposable measurement cells (DTS 1070, Malvern). All measurements were obtained in triplicate.

The pattern of the size distribution and zeta potential were assessed by a dynamic light scattering (DLS) system by a Zetasizer (NANO ZSP, Malvern Instruments Ltd., Serial Number: MAL1118778, version 7.11, Malvern, UK) [67 (link)].