## 3 Materials and Methods  
### General  
Commercial reagents and solvents were purchased as follows: \(\gamma\)-butylrolactone (dihy drofuran-2(3_H_)-one), (\(\pm\))-ectoine (45)-2-methyl-1,4,5,6-tetrahydroropirimidine-4-carboxylic acid and \(N\),_N_-diethyllethanamine (Et\({}_{3}\)N) from Sigma Aldrich (Munich, Germany), bromine (Br\({}_{2}\)) and copper(II) acetate monohydrate [Cu(CH\({}_{3}\)COO)\({}_{2}\)\(\times\) H\({}_{2}\)O] from Fluka (Buchs, Switzerland), phosphorus tribromide (PhBr\({}_{3}\)) and potassium phthalimide from Merck (Darmstadt, Germany), quinolin-8-ol, sodium carbonate (Na\({}_{2}\)CO\({}_{3}\)), sodium hydroxide (NaOH), sodium chloride (NaCl), anhydrous sodium sulfate (Na\({}_{2}\)SO\({}_{4}\)), glacial acetic acid (AcOH), and hydrochloric acid (HCl) from Kemika (Zagreb, Croatia), and dimethylformamide (DMF), acetonitrile (ACN), _n_-butanol (_n_-BuOH), isopropanol (i-ProOH), methanol (MeOH), acetone, dichloromethane (DCM), and ethanol (EtOH) from [PERSON] (Van de Reuil, France). Thin-layer chromatography (TLC) was performed on silica-gel plates TLC silica gel 60 F254 (Merck, Darmstadt, Germany) in different solvent systems: **A**, EtOH:hexane 9:1;  
Figure 4: Chromatograms of (**a**) (+)-ectoine, (**b**) sample 6, (**c**) sample 15, and (**d**) sample 16. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Strain Code * & _w_**(NaCl) [\%]** & **c ((+)-Ectoine) [\%/mL]** \\ \hline
1 ** & Sc & 0 & 0 \\
2 ** & Sc & 3 & 13.4 \\
3 ** & Sc & 6 & 55.8 \\
4 & BC81 & 0 & 0 \\
5 & BC81 & 3 & 18.3 \\
6 & BC81 & 6 & 64.2 \\
7 & BC104 & 9 & 10.7 \\
8 & BC114 & 9 & 25.6 \\
9 & BC115 & 9 & 11.4 \\
10 & BC121 & 9 & 18.6 \\
11 & BC123 & 9 & 9.6 \\
12 & BC126 & 9 & 12.8 \\
13 & BC131 & 9 & 7.9 \\
14 & BC156 & 9 & 6.7 \\
15 & BC160 & 9 & 9.5 \\
16 & BC167 & 9 & 58.2 \\ \hline \hline \end{tabular}
* Strain identification by 16 srRNA is shown in Table S2. ** Reference strain _S. exelicolor_.  
\end{table} 
Table 2: HPLC detection of (+)-ectoine in the fermentation broth of salt-tolerant _Streptomyces_ strains isolated from the Adriatic Sea. B, DCM:MeOH 25:1; **C**, _i_-PrOH:AcOH:H_2O 7:3:2. Spots were detected with UV/254 nm, and/or KMnO\({}_{4}\) or ninhydrin reagent, followed by heating. The preparative TLC was performed on Analtec Silica gel GF 254, 20,000 uM from Merck (Damstad, Germany). The compounds were characterized using \({}^{1}\)H and \({}^{13}\)C NMR spectra recorded on Bruker Technologies (Ettlingen and Leipzig, Germany) AV 300, 25 \({}^{\circ}\)C, 300 MHz (\({}^{1}\)H) and 75 MHz (\({}^{13}\)C) in deuterated chloroform (CDCl\({}_{3}\)), deuterated water (D\({}_{2}\)O), deuterated dimethyl sulfoxide (DMSO-\(d_{\delta}\)) and deuterated methanol (CD\({}_{3}\)OD). The spectra were visualized with MestReNova. Chemical shifts (\(\delta\)) were expressed as parts per million (ppm). The internal standard in the \({}^{1}\)H spectra was tetramethylsilane (TMS), and in the \({}^{13}\)C spectra dioxane-\(d_{\delta}\) or solvent signal. IR spectra were recorded on PerkinElmer UATR Two spectrometer PerkinElmer Inc., Waltman, MA, USA) using the ATR method in the range of 450 to 4000 cm\({}^{-1}\), with a resolution of 4 cm\({}^{-1}\) and 8 scans per spectrum. Melting points were determined using an Olympus BX51 polarizing microscope equipped with a Linkam TH600 hot stage and PR600 temperature controller and the Olympus C 5050 ZOOM digital camera (Olympus, Tokyo, Japan). Speed of cycles of heating samples was 5 \({}^{\circ}\)C/min. An Agilent 8860 (Waldbronn, Germany) GC system with FID detector and autosampler was used to monitor preparation of 3-bromodhydrofurane-2-(3\(H\))-one. An Agilent Technologies HP-5 (30 m \(\times\) 0.35 mm, 0.25 um) column was used. Heating method: 0\(\rightarrow\)2 min 100 \({}^{\circ}\)C; 3 min 110 \({}^{\circ}\)C; 4 min 120 \({}^{\circ}\)C; 5 min 130 \({}^{\circ}\)C; 6 min 140 \({}^{\circ}\)C; 7 min 150 \({}^{\circ}\)C. The samples were prepared by dissolving 1 mg in 1 mL DCM, and 2 uL of these solutions were injected.