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Table 1 The specific enzyme activities of ALS (AHAS), ALDC, and AR/BDH were determined in recombinant C. crenatum cell extracts

From: Synthetic engineering of Corynebacterium crenatum to selectively produce acetoin or 2,3-butanediol by one step bioconversion method

Strains Specific enzyme activity (U mg−1)
ALS (AHAS) ALDC AR/BDH
C. crenatum WT 0.01 ± 0.01 0 0.05 ± 0.01/0.01 ± 0.01
C. crenatum S 4.86 ± 0.85 nd nd
C. crenatum D nd 13.59 ± 1.22 nd
C. crenatum A nd nd 0.38 ± 0.03/0.19 ± 0.01
C. crenatum SD 2.22 ± 0.43 8.08 ± 0.94 nd
C. crenatum SDA 2.32 ± 0.31 5.68 ± 0.87 0.32 ± 0.02/0.10 ± 0.01
  1. Using C. crenatum WT as positive control, 1% recombinant strains were transferred to 10 mL LBG medium with 10 g mL−1 chloramphenicol. After 12 h of activation, 1% bacterial solution was transferred to 50 mL LBG liquid medium. After incubation for 3–4 h at 30 °C, 180 r min−1, the expression of heterologous enzyme in the recombinants was induced by adding 1 mM IPTG and incubated for 12 h. Specific enzymatic activities of ALS (AHAS), ALDC, and AR/BDH in the crude enzyme solution were assayed after disrupting the recombinant cells with sonicator. The specific enzyme activity results are the mean ± standard of three replicates
  2. nd not detected