Phenylethylamine

The following chemicals were purchased at highest purities available from Sigma Aldrich, Bangalore, India: 2-methyltetrahydro-3-furanone, acetic acid, benzaldehyde, 1-octanol, (R)-1-octen-3-ol, ethyl butyrate, ethyl acetate, geranyl acetate, methyl salicylate, methyl laurate, isopentyl acetate, hexanoic acid, 2-methylphenol, geosmin, butyraldehyde, 1,4-diaminobutane, phenyl acetalydehyde, phenylethylamine, pyridine, ammonia solution and mineral oil. 11-cis-vaccenyl acetate was purchased from Cayman Chemical Company, Michigan, United States. Cis-3-hexenyl acetate, 2,3-butanedione, butyric acid, linalool, and acetophenone were purchased from Fluka, Sigma-Aldrich, Bangalore, India. The compound 1-hexanol was purchased from TCI, nonanal was purchased from Acros Organics. Propionic acid was obtained as a gift from the Max Planck Institute for Chemical Ecology, Jena, Germany. Fluo-4AM was purchased from Life Technologies, Stockholm, Sweden.

The alternating aliphatic polyketone (PK30; CO, ethylene, propylene: 50, 30, and 20 mol %, respectively, M_W = 2687 g/mol) was synthesized according to a reported procedure [40 ]. 2-thiophenemethylamine (TMA, pure), n-butylamine (nBuA, ≥99%), phenylethylamine (PEA, 99%), and 1-pyrenemethylamine hydrochloride (PMA, 95%) were purchased from Sigma-Aldrich (Darmstadt, Germany) and freshly distilled before use. Multi-walled carbon nanotubes (MWCNTs, Sigma-Aldrich, as-produced cathode deposit, >7.5% MWCNT basis, O.D. × L 7–15 nm × 0.5–10 μm) were used as an electrically conductive filler and used as received. Dimethylsulfoxide (DMSO, Acros, 99.7%), ammonia (Sigma-Aldrich, ca. 25), toluene (anhydrous, 99.8%, Sigma-Aldrich,), tetrahydrofuran (THF ≥ 99.9, Sigma-Aldrich), and methanol (Sigma-Aldrich, anhydrous, 99.8%) were used as received. Dimethyl sulfoxide-d6 (DMSO-d6, anhydrous, 99.9 atom % D, Sigma-Aldrich) was used as a deuterated solvent for ¹H-NMR studies.

To evaluate the capacity of S. hirsuta J2 to produce BAs, that strain was inoculated at a level of 1 × 10⁷ cells/mL in Gauzeˊs liquid medium (Guangdong Huankai Microbial Sci. & Tech.co., Ltd, China) containing 1.0 g/L of either histidine, tyrosine, tryptophan, phenylalanine, ornithine monohydrochloride, lysine, or agmatine sulfate salt and incubated at 30 °C for 24 h. All amino acids were purchased from Sigma. Negative controls were not inoculated. BAs quantification was performed as previously described^{62 (link)} using an RP-HPLC system (Waters e2695, Milford, MA) equipped with an XBridge C18 (250 mm × 4.6 mm, 5 µm) and UV detector.
For quantification of the capacity of S. hirsuta J2 to consume BAs, S. hirsuta J2 was inoculated into Gauzeˊs liquid medium containing 50 mg/L each of histamine, tyramine, cadaverine, putrescine, spermine, spermidine, tryptamine, and phenylethylamine (each from Sigma). All cultures, including the negative control, were incubated at 30 °C for 5 days. BA consumption was measured by collecting S. hirsuta by centrifugation at 10,000 g for 10 min and then using the supernatant to measure BA concentrations by HPLC. S. hirsuta J2 BA degradation was calculated according to the formula: $\text{BAs degradation}\left(\mathrm{\%}\right)=\left[\right(A-B\left)/A\right]\times 100\mathrm{\%}$
A was the concentration of BA in the negative controls and B was the concentration of the BA in the medium incubated with S. hirsuta J2.