Yeast extract

All strains used in this study were derived from the haploid auxotrophic S288c strain BY4741 (MATa). A full list of strains used can be found in Table S1. Primers used for strain construction and verification were ordered from IDT. Primer sequences are listed in Table S2.
Deletion strains were constructed with a HygB cassette amplified from the pCB1 plasmid using primers with at least 40 bp sequence homology to the target DNA [74 (link)]. For fluorescent tagging, yECitrine was amplified from the pKT140 plasmid using primers with 40 bp sequence homology to the target DNA [75 (link)]. A list of plasmids used in this study and their genotype can be found in Table S3. PCR products were used for yeast transformation using a LiAc-based procedure. Transformants were verified by PCR using specific check primers.
Yeast was cultured in peptone dextrose (YPD) medium containing 2% bacteriological peptone (Lab M, Heywood, UK), 1% yeast extract (Lab M, Heywood, UK) and 2% glucose (Sigma, St. Louis, MO, USA). For solid plates 2% agar (Lab M, Heywood, UK) was added. YPD containing 200 µg/L Hygromycin B (Invitrogen, Waltham, MA, USA) or 200 µg/mL G418 (Formedium, Swaffham, UK) was used for selection of yeast transformants.

Kombucha SCOBY (symbiotic colony of bacteria and yeast) was obtained from Sri Dhanvanthiri Probiotics Ltd., Kodaikanal, India (True Brew Kombucha tea). Sodium chloride, sodium molybdate, potassium chloride, di sodium hydrogen phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, calcium carbonate, calcium chloride, magnesium sulfate, disodium hydrogen phosphate, citric acid, bromothymol blue and oxidase test disks (product no: 70439) were purchased from Merck (Darmstadt, Germany). Acetic acid and agar were purchased from Fisher Scientific (Loughborough, UK). Glucose and casein amino acids were purchased from VWR International (Leuven, Belgium). Tryptone, peptone and yeast extract were from Lab M Limited (Heywood, UK). Ethanol was from Altia Oyj (Helsinki, Finland). Cycloheximide (Product no: C7698), and cellulase from Trichoderma reesei ATCC 26921 (product no: C2730) was purchased from Sigma-Aldrich (St. Louis, MO, USA). GeneJET Genomic DNA Purification Kit was purchased from Thermo Scientific (Waltham, MA, USA). Crude glycerol was generously provided by Perstorp AB (Malmo, Sweden).

Sodium chloride (NaCl, ≥99%, Taufkirchen, Germany), sodium hydroxide (NaOH, Prague, Czech Republic), silver nitrate (AgNO₃, >99.8%, Gillingham, UK), 2′, 7′ Dichlorofluorescin diacetate (C₂₄H₁₆Cl₂O₇, ≥98%, Rehovot, Israel), ethylene-co-vinyl acetate polymer (EVA, 40 wt.%, Taufkirchen, Germany), dichloromethane (CH₂Cl₂, Taufkirchen, Germany), poly(vinyl pyrrolidone) (PVP, Mw 1,300,000 by LS, St. Louis, MO, USA) and phosphate buffered saline (PBS, pH 7.4, Taufkirchen, Germany) were purchased from Sigma Aldrich and used as received. Iron (III) nitrate nonahydrate (Fe(NO₃)₃∙9H₂O, ≥98%, Darmstadt, Germany), hexane (C₆H₁₄, ≥97.0%, Rosh-Ha’ayin, Israel), and Nutrient agar (NA, Darmstadt, Germany) were purchased from Merck. Tryptone, yeast extract, meat extract, and agar were obtained from LabM (Heywood, UK). All chemicals were purchased as analytical reagent (AR) grade and used without further purification. High purity deionized (DI) water obtained from a Milli-Q^® system (Merck Millipore, Darmstadt, Germany) was used for all the tests.