Octane

Oleic acid (OA, analytical reagent), oleylamine
(OAm, technical grade 80–90%), and 1-octadecene (ODE, technical
grade 90%) were purchased from Aladdin Bio-Chem Technology Corp. Cesium
acetate (CsAc, 99.99%) and τitanium(IV) isopropoxide (TIPP,
99.999% trace metals bases), octane (anhydrous, ≥99%), methyl
acetate (MeOAc, anhydrous 99.5%), 4-tert-butylpyridine
(tBP, 96%), chlorobenzene (anhydrous, 99.8%), acetonitrile (anhydrous,
99.8%), molybdenum(VI) oxide (MoOx, 99.97% trace metals basis), bis(trifluoromethane)
sulfonimide lithium salt (Li-TFSI, 99.95% trace metals basis), and
FK 102 Co(III) TFSI Salt (98%) were purchased from Sigma-Aldrich.
Lead(II) iodide (PbI₂, 99.99%) was purchased from Xi’an
Polymer Light Technology Corp. Hexane (GR grade 95%) was purchased
from DUKSAN. Spiro-OMeTAD was purchased from YingKou YouXuan Technology
Corp. HCl (37%) HNO₃ (68%), and EtOH were purchased from
RCL Labscan Limited. All of the chemicals were used without further
purification.

Formamidinium iodide (CH(NH₂)₂, FAI) was purchased from Dyesol. Lead (II) iodide (PbI₂; 99.9985%) and bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) were purchased from Alfa Aesar. 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamino)−9,9′-spirobifluorene (spiro-OMeTAD; ≥99.5%) was purchased from Lumtec. Cesium carbonate (Cs₂CO₃; 99.9%), oleylamine (OAm; technical grade, 70%), oleic acid (OA; technical grade, 90%), 1-octadecene (ODE; technical grade, 90%), octane (anhydrous, ≥99%), hexane (reagent grade, ≥95%), methyl acetate (MeOAc; anhydrous, 99.5%), lead nitrate (Pb(NO₃)₂; 99.999%), ethyl acetate (EtOAc; anhydrous, 99.8%), formamidinium acetate (FA-acetate, 99%), titanium ethoxide (≥97%), hydrochloric acid (HCl; 37% in water), chlorobenzene (anhydrous, 99.8%), 4-tert-butylpyridine (4-TBP; 96%), toluene (anhydrous, 99.8%), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile (anhydrous, 99.8%) were purchased from Sigma-Aldrich and used as received unless otherwise specified.

Octane (≥99.0%) from Sigma Aldrich (St. Louis, MO, USA), hematoxylin (hematoxylin solution according to Mayer) from Sigma Aldrich (St. Louis, MO, USA) and eosin (Eosin Y) from Sigma Aldrich (St. Louis, MO, USA) were used for the sample preparation. All samples were mounted on infrared-transparent CaF2 slides, 1 mm thick (KORTH KRISTALLE GmbH, Altenholz, Germany) and 1 mm thick (Menzel slides, Fisher Scientific, Vienna, Austria).

A GC-MS 7890B gas chromatograph equipped with a 5977B MSD mass spectrometer (Agilent Technologies, Santa Clara, CA, USA), with an Agilent HP-5MS column (30 m, 0.25 µm, 0.25 μm film thickness) was used in the experiments. The carrier gas used was helium at 99.999% (BOC, Sydney, Australia). The conditions for the GC-MS were as follows: injector port temperature of 270 °C; initial oven temperature of 60 °C, which increased to 320 °C (at 5 °C/min); MS Quad at 150 °C; MS source at 230 °C; pressure at 10.629 psi. The flow rate was 1.2 mL/min; the splitless was 30 mL/min at 1.0 min. The total run time was 45.40 min.
Standard n-alkane (C₇-C₃₀) reference material containing 1000 μg/mL of each component (decane, docosane, dodecane, eicosane, heneicosane, heptacosane, heptadecane, hexacosane, hexadecane, heptane, nonacosane, nonadecane, nonane, octacosane, octadecane, octane, pentacosane, pentadecane, tetracosane, tetradecane, triacontane, tricosane, tridecane and undecane) in hexane was purchased from Sigma-Aldrich (catalogue number 49451-U; Castle Hill, NSW, Australia), as was n-hexane (95%, catalogue number 270504-2L).

Formamidinium acetate (FA-acetate, 99%),
oleic acid (OA, technical grade 90%), oleylamine (OAm, technical grade
70%), 1-octadecene (ODE, technical grade 90%), hexane (reagent grade
≥95%), octane (anhydrous, ≥99%), methyl acetate (MeOAc,
anhydrous 99.5%), ethyl acetate (EtOAc, anhydrous 99.5%), R-methybenzylamine (98% purity), S-methybenzylamine
(98% purity), hydrobromic acid (ACS reagent, 48%), and ethyl acetate
(EtOAc, anhydrous, 99.8%) were purchased from Sigma-Aldrich. (R)-2-Octylamine (98% purity) was purchased from Alfa Aesar.

Hydrophobic features of yeast surface were determined by measuring their affinity for a nonpolar solvent as described in Purevdorj-Gage et al., 2007 (link). Overnight cultures were centrifuged at 2.000 g for 5 min and resuspended in fresh YN galactose medium at OD₆₀₀ of 1. After 3 hr of static incubation at room temperature, OD_{600 nm} was measured (A0) and 1.2 ml of each culture was overlaid with 0.6 ml of octane (Sigma-Aldrich) in 15 × 100 mm borosilicate glass tubes. The tubes were vigorously vortexed for 2 min and left on the bench for at least 15 min until complete separation of the two phases. A sample of the aqueous phase was taken with a Pasteur pipette and the OD_{600 nm} was measured (A). The results were expressed as the octane adhesion index (% hydrophobicity), which represents the percentage of cells retained by the organic fraction, according to the equation: $Hydrophobicity=1-\left(\frac{A}{A0}\right)*100$

Hydrophobic properties of yeasts strains were determined by measuring their affinity for an apolar solvent as described in Purevdorj-Gage et al. (2007 (link)). Briefly, overnight cultures were centrifuged at 2,000 g for 5 min and resuspended in fresh YPD medium to obtain an optical density of 1 at 600 nm. After 3 h of incubation at room temperature, the OD₆₀₀ was measured for each culture. In 15 × 100 mm borosilicate glass tubes 0.6 ml of octane (Sigma-Aldrich) was added to 1.2 ml of yeast cell suspension. The mixtures were vortexed for 120 s and allowed to stand for 15 min at room temperature to achieve the complete separation of the two phases. The aqueous phase was recovered and its OD₆₀₀ measured. The results were expressed as the octane adhesion index, (% A) which represents the percentage of cells retained by the organic fraction, according to the relationship: % A = [A₀-A_F/A_F] × 100. A₀ and A_F represent the optical density at 600 nm of the yeast suspension before and after contact with octane. Assays were performed in triplicates.