Potassium Phosphate, Tribasic → Gamma-Valerolactone

Beteiligte Stoffe

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coli MBX769 carrying the plasmid pFS16 (FIG. 2), which permitted the expression of the Clostridium kluyveri 4-hydroxybutyryl-CoA transferase, was precultured at 37° C. in 100 mL of LB medium containing 100 μg/mL sodium ampicillin in a 250-mL Erlenmeyer flask with shaking at 200 rpm. The cells were centrifuged at 5000 g for 10 minutes to remove them from the LB medium after 16 hours, and they were resuspended in 100 mL of a medium containing, per liter: 4.1 or 12.4 g sodium 4-hydroxyvalerate (4HV); 5 g/L sodium 4-hydroxybutyrate (4HB); 2 g glucose; 2.5 g LB broth powder (Difco; Detroit, Mich.); 50 mmol potassium phosphate, pH7; 100 μg/mL sodium ampicillin; and 0.1 mmol isopropyl-β-D-thiogalactopyranoside (IPTG). The sodium 4-hydroxyvalerate was obtained by saponification of γ-valerolactone in a solution of sodium hydroxide. The cells were incubated in this medium for 3 days with shaking at 200 rpm at 32° C. in the same flask in which they had been precultured. When 4.1 g/L sodium 4-hydroxyvalerate was present initially, the cells accumulated a polymer to 52.6% of the dry cell weight that consisted of 63.4% 3HB units and 36.6% 4HB units but no 4HV units.

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