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Improved Production of Recombinant Human β-NGF in Escherichia coli – a Bioreactor Scale Study


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Fig. 1.

The recombinant protein expression level analysis in different post induction times. (A) Western blot analysis of the proteins extracted from recombinant bacteria carrying pET39::β-NGF plasmid using anti-histag. HRP antibody. (B) % recombinant protein expression level measured by ImageJ software. All experiments were repeated three times under the identical experimental conditions.
The recombinant protein expression level analysis in different post induction times. (A) Western blot analysis of the proteins extracted from recombinant bacteria carrying pET39::β-NGF plasmid using anti-histag. HRP antibody. (B) % recombinant protein expression level measured by ImageJ software. All experiments were repeated three times under the identical experimental conditions.

Fig. 2.

The recombinant protein expression level analysis in different % DO and post induction temperature. (A) Western blot analysis of the proteins extracted from recombinant bacteria carrying pET39::β-NGF plasmid using anti-histag.HRP antibody. (B) % recombinant protein expression level measured by ImageJ software and comparison with the cell growth measured by absorbance at 600 nm. All experiments were repeated three times under the identical experimental conditions.
The recombinant protein expression level analysis in different % DO and post induction temperature. (A) Western blot analysis of the proteins extracted from recombinant bacteria carrying pET39::β-NGF plasmid using anti-histag.HRP antibody. (B) % recombinant protein expression level measured by ImageJ software and comparison with the cell growth measured by absorbance at 600 nm. All experiments were repeated three times under the identical experimental conditions.

Fig. 3.

Normal (%) probability plot of the studentized residuals for the model of recombinant β-NGF production (A) and cell growth (B).
Normal (%) probability plot of the studentized residuals for the model of recombinant β-NGF production (A) and cell growth (B).

Fig. 4.

Response surface plots and their counter plots show the effect of post induction temperature and % dissolved oxygen on the protein (β-NGF) expression level (A and B) and cell growth (C and D).
Response surface plots and their counter plots show the effect of post induction temperature and % dissolved oxygen on the protein (β-NGF) expression level (A and B) and cell growth (C and D).

The values of independent variables (post induction temperature and dissolved oxygen) and the corresponding levels used in a central composite design (normalized in –2, –1, 0, 1 and 2).

VariableLevel
–2–1012
A: Post induction temperature (T) (°C)2024.2528.532.7537
B: Dissolved oxygen (DO) (%)1020304050

The experimental design of 10 runs with two variables (post induction temperature and dissolved oxygen) and two responses (recombinant protein expression level and cell growth measured by absorbance at 600 nm).

RunPost induction Temperature (T) (°C)Dissolved Oxygen (DO) (%)Response 1 Recombinant Protein Expression Level (%)Response 2 Cell Growth (Abs 600nm)
1–124.25–1208.0 ± 0.91.83 ± 0.18
2+132.75–12015.3 ± 1.22.60 ± 0.19
3–124.25+14010.1 ± 1.01.02 ± 0.11
4+132.75+1408.4 ± 0.85.60 ± 0.29
5–220.00304.6 ± 0.41.36 ± 0.11
6+237.003011.1 ± 1.13.40 ± 0.22
7028.5–21010.0 ± 0.91.87 ± 0.21
8028.5+2503.8 ± 0.42.05 ± 0.20
9028.503014.6 ± 1.22.45 ± 0.19
10028.503014.2 ± 1.22.60 ± 0.19

Parameter estimates and analysis of variance (ANOVA) of the model for recombinant production of β-NGF in E. coli and for cell growth.

Source of variationDegree of freedomSum of squaresMean squaresF-valuep value (Probe > F)
Recombinant Protein Expression Level (%)Model5141.5028.30120.360.0002
A-Temperature (°C)1  29.1429.14123.940.0004
B-Dissolved Oxygen (%)1  24.6524.65104.850.0005
AB1  20.2520.25  86.130.0007
A21  42.9442.94182.620.0002
B21  56.1756.17238.900.0001
Error1    0.058    0.058
Total9142.44
Cell Growth (Abs 600 nm)Model3  11.58  3.86    6.820.0232
A-Temperature (°C)1    7.41  7.41  13.100.0111
B-Dissolved Oxygen (%)1    0.54  0.54    0.960.3655
AB1    3.63  3.63    6.410.0445
Error1    0.011  0.011
Total9  14.98
eISSN:
2544-4646
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Inglés
Calendario de la edición:
4 veces al año
Temas de la revista:
Life Sciences, Microbiology and Virology