621 HYL MEDIUM
| HEPES | 4.76 | g |
| NaCl | 20.0 | g |
| Na2SO4 | 4.0 | g |
| MgCl2·6H2O | 4.3 | g |
| NH4Cl | 0.25 | g |
| KCl | 0.34 | g |
| CaCl2·2H2O | 0.14 | g |
| K2HPO4 | 0.14 | g |
| Yeast extract | 1.0 | g |
| Sodium lactate solution (50%) | 4.5 | ml |
| Resazurin | 1.0 | mg |
| Distilled water | 1.0 | L |
| Trace elements (see below) | 1.0 | ml |
| 0.2% Fe(NH4)2(SO4)·6H2O (in 0.037% HCl) | 1.0 | ml |
| Trace vitamins (see Medium No. 197) | 10.0 | ml |
| 0.5 M Na2S·9H2O solution | 4.0 | ml |
| EDTA·2Na | 29.0 | g |
| MnSO4·xH2O | 3.26 | g |
| CoCl2·6H2O | 1.8 | g |
| ZnSO4·7H2O | 1.0 | g |
| NiSO4·6H2O | 0.11 | g |
| CuSO4·5H2O | 0.1 | g |
| H3BO3 | 0.1 | g |
| KAl(SO4)2·12H2O | 0.1 | g |
| Na2MoO4·2H2O | 0.1 | g |
| Na2WO4·2H2O | 0.1 | g |
| Na2SeO3 | 0.05 | g |
| Distilled water | 1.0 | L |