Table 2. The main byproducts formation in L-arginine fed-batch fermentations of different strains.
| Strain | Lysine (g L−1) | Isoleucine (g L−1) | Proline (g L−1) | Acetate (g L−1) | Lactate (g L−1) |
|---|---|---|---|---|---|
| Cc0 | 2.53 ± 0.38 | 2.24 ± 0.25 | 1.16 ± 0.21 | 0.87 ± 0.21 | 1.83 ± 0.13 |
| Cc1 | 1.94 ± 0.29 | 1.82 ± 0.18 | 0.57 ± 0.16 | 0.69 ± 0.14 | 1.42 ± 0.17 |
| Cc2-6500 | 4.12 ± 0.64 | 3.06 ± 0.47 | 1.38 ± 0.25 | 0.36 ± 0.08 | 0.54 ± 0.08 |
| Cc3 | 4.36 ± 0.55 | 2.85 ± 0.36 | 1.56 ± 0.27 | 1.84 ± 0.39 | 4.32 ± 0.87 |
| Cc4 | 4.63 ± 0.59 | 3.18 ± 0.43 | 1.71 ± 0.23 | 0.49 ± 0.08 | 0.67 ± 0.06 |
| Cc5-800 | 3.74 ± 0.46 | 2.83 ± 0.38 | 2.12 ± 0.30 | 0.31 ± 0.07 | 0.42 ± 0.05 |
| Cc6 | 0.61 ± 0.17 | 0.39 ± 0.12 | Not detected | 0.23 ± 0.05 | 0.37 ± 0.05 |
Cc0: parent strain C. crenatum SYPA5-5; Cc1: Cc0+replacement of the natural argB gene by mutated argBM3 gene, and replacement of the natural promoters of the argCJBDFR and argGH operons by the eftu promoter; Cc2-6500: Cc1+replacement of the natural RBS (11290 au of activity) of pgi gene by weaker RBS (6500 au of activity); Cc3: Cc2-6500+replacement of the natural promoters of the ptsG gene, iolT1 gene and ppgk gene by the sod promoter; Cc4: Cc3+replacement of the start codon GTG by ATG in the pyc gene and implementation of an additional copy of gltA gene on chromosome; Cc5-800: Cc4+implementation of an additional copy of icd gene and gdh gene on chromosome, respectively, and replacement of the natural RBS (1613 au of activity) of odhA gene by weaker RBS (800 au of activity); Cc6: Cc5-800+replacement of the natural RBS (131 au of activity) of lysC gene by weaker RBS (30 au of activity) and deletion of proB gene. The contents of the other byproducts were very low (≤0.50 g L−1). SDs based on three biologically independent experiments.