Acetonitril

Tobramycin (TOB) was a gift sample from Welmark Pharmaceuticals (Hattar, Pakistan). Docusate sodium (DOC), sodium dodecanoate (DOD), Propylene glycol and acetonitril were obtained from Sigma-Aldrich (Darmstadt, Germany). Peceol (glycerol monooleate, HLB = 3), Cremophor RH (castor oil, hydrogenated, ethoxylated) and Maisine 35–1 (glycerol monolinoleate, HLB = 1) were a gift from Gattefossé (Lyon France).

Cell pellets were thawed and transferred from Eppendorf tube into degreased glass tubes (100 x 10 mm) using 3 x 0.5 ml of methanol. After each addition of methanol, cell pellet was homogenized by sonication in a water bath. Following this procedure, 0.75 ml of chloroform and 0.3 ml of water were added into tube; its content was dispersed using a probe sonicator and extraction process continued at RT overnight. The monophase extraction system was dried by nitrogen at room temperature. For reconstitution of lipids, 0.3 ml of solvent mixture (methanol/chloroform 1/1 vol. %) was used. This concentrated extract was then used for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of lipids, performed using Agilent 1200 high performance liquid chromatography (HPLC) System (Agilent, Santa Clara, CA, USA) and mass spectrometer TripleQuad 6410, equipped with electrospray ionization (ESI) and atmospheric pressure photoionization (APPI), respectively (Agilent). Methanol, chloroform, acetonitril, hexane, isopropanol, formic acid, ammonium formate were purchased from Sigma-Aldrich; HPLC columns Supelcosil LC SI–(250 mm x 2.1 mm; 3 μm), Supelcosil LC DIOL (250 mm x 3 mm; 5 μm) were used for lipid separation.

Defatted rice bran was provided by Wilmar Agro Vietnam (Can Tho, Vietnam). Cellulase preparation was provided by Novozymes (Bagsvaerd, Denmark) and delivered by Trung Son Technology (Ho Chi Minh City, Vietnam). The cellulase preparation is in brown color, noted with an activity of 700 EGU/g and the best-storing temperature of 4 °C. Standard FOS set, including GF2, GF3, and GF4, with a purity 99% was purchased from Fujifilm Wako Pure Chemical Corporation (Osaka, Japan). Acetonitril, water, and methanol for UPLC analysis were from Merck (Darmstadt, Germany).