Mgso4

All reagents and chemicals were of analytical grade and applied without further purification. HPLC-grade deionized water was used during all experiments.
α-KG, 5-HMF, NASeLM, NALM, and glucose were supplied by CYL-Pharma (Lassnitzhöhe, Austria). NaCl, KCl, KH₂PO₄, MgSO₄, CaCl₂, NaHCO₃, and dextrose were obtained from Roth (Karlsruhe, Germany). Acetonitrile, ammonium acetate, 1-butanol, ethanol, HPLC-grade water, hydrogen peroxide, and HCl were obtained from Merck (Darmstadt, Germany). Albumin from human serum, angiotensin 1-7 acetate salt hydrate, butylated hydroxytoluene (BHT), 2,4-dinitrophenylhydrazine (DNPH), ethyl acetate, guanidine-hydrochloride, malondialdehyde tetra-butyl-ammonium salt (MDA), 2-thiobarbituric acid (TBA), trichloroacetic acid (TCA), and tris(hydroxymethyl)aminomethane (Tris) were obtained from Sigma-Aldrich (Vienna, Austria).

We screened individual media components, using a Plackett–Burman design with 12 ((n₁ + n₂) + 1) runs, 9 (n₁) factors, and 2 (n₂) dummies, to estimate the occurring falsification related to cumulative interaction components, as shown in Table 1. We optimized the process with regard to a maximum specific pDNA yield (ng pDNA/ODV) (OD₆₀₀ × culture volume = ODV) and the E. coli biomass (determined as OD₆₀₀). The following components were used for this purpose: LB powder (consists of 10 g/L trypton, 5 g/L yeast extract, 10 g/L NaCl) (Carl Roth), meat peptone (Fluka Analytical), casein peptone (Carl Roth), yeast extract (Carl Roth), glucose (Carl Roth), glycerol (Carl Roth), phosphate (Carl Roth), NaCl (Carl Roth), and MgSO₄ (Carl Roth). Experiments were performed in 500 mL shake flasks and harvested and tested after 18 h.

Basic medium (B medium) for Staphylococci consisted of Soy Peptone (10 g; Plato, Koblenz, Germany), Yeast Extract (5 g; Deutsche Hefewerke, Nuernberg, Germany), NaCl (5 g; Carl-Roth, Karlsruhe, Germany), Glucose (1 g; Carl Roth) and K₂HPO₄ (1 g; Applichem, Darmstadt, Germany). Deionized water was added to a final volume of 1 liter and pH was adjusted to 7.2.
LB medium for E. coli consisted of Peptone (10 g; Plato), Yeast Extract (5 g; Deutsche Hefewerke) and NaCl (5 g; Carl Roth). Deionized water was added to a final volume of 1 liter and pH was adjusted to 7.2. MacConkey agar was prepared according to the manufactures’ instructions (Carl Roth). Minimal media M9 for staphylococci consisted of Na₂HPO₄ (6 g; Carl Roth), KH₂PO₄ (3 g; Fisher Chemicals), NH₄Cl (1 g; Merck Darmstadt, Germany) and NaCl (0.5 g; Carl Roth). Deionized water was added to a final volume of 1 L, the media was autoclaved and supplemented with thiamine (2 µg/mL; Sigma Aldrich, Munich, Germany), MgSO₄ (1 mM; Carl Roth) and casamino acids (0.2%; BD Bioscience, Heidelberg, Germany). Cells were routinely grown at 37 °C either in liquid culture in baffled Erlenmeyer flasks (1:5 ratio) with shaking or on 1.5% agar plates.