J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (12): 2447-2457.DOI: 10.1016/j.jmst.2018.05.019
Special Issue: Corrosion in 2018
• Orginal Article • Previous Articles Next Articles
Masoumeh Moradia, Zhenlun Songa*(), Tao Xiaoab
Received:
2017-11-17
Revised:
2018-02-19
Accepted:
2018-03-30
Online:
2018-12-20
Published:
2018-11-15
Contact:
Song Zhenlun
Masoumeh Moradi, Zhenlun Song, Tao Xiao. Exopolysaccharide produced by Vibrio neocaledonicus sp. as a green corrosion inhibitor: Production and structural characterization[J]. J. Mater. Sci. Technol., 2018, 34(12): 2447-2457.
Fig. 1. (a) TGA and DSC curves of the thermal degradation EPS with a heating rate of 10 °C min-1; (b) FTIR; and (c) XPS analysis performed on the exopolysaccharides produced by Vibrio neocaledonicus sp. after 3 days’ incubation in artificial seawater plus peptone in shaker incubator at 130 rpm and 30 °C; (d) and Elution profiles of EPS.
Sample | Tafel extrapolation | Weight loss measurement | |||||
---|---|---|---|---|---|---|---|
Cinh | Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | Weight loss ± SD (mg) | CR (mpy) |
0 | -0.892 | 21.34 ± 0.36 | 91 | -263 | - | 56.25 ± 2.27 | 1562.29 |
1 g/L | -0.977 | 13.43 ± 0.17 | 81 | -192 | 37.1 | 38.19 ± 3.15 | 1060.69 |
3 g/L | -1.012 | 6.67 ± 0.09 | 67 | -166 | 68.7 | 16.79 ± 1.85 | 466.32 |
5 g/L | -0.883 | 1.46 ± 0.03 | 97 | -86 | 93.2 | 3.55 ± 0.08 | 98.59 |
10 g/L | -0.928 | 1.28 ± 0.04 | 148 | -84 | 94.0 | 2.98 ± 0.09 | 82.77 |
Table 1 Fitted results of potentiodynamic polarization measurements and weight loss data of A36 CS in artificial seawater in the absence and presence of different concentrations of EPS after 7 days’ exposure at room temperature.
Sample | Tafel extrapolation | Weight loss measurement | |||||
---|---|---|---|---|---|---|---|
Cinh | Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | Weight loss ± SD (mg) | CR (mpy) |
0 | -0.892 | 21.34 ± 0.36 | 91 | -263 | - | 56.25 ± 2.27 | 1562.29 |
1 g/L | -0.977 | 13.43 ± 0.17 | 81 | -192 | 37.1 | 38.19 ± 3.15 | 1060.69 |
3 g/L | -1.012 | 6.67 ± 0.09 | 67 | -166 | 68.7 | 16.79 ± 1.85 | 466.32 |
5 g/L | -0.883 | 1.46 ± 0.03 | 97 | -86 | 93.2 | 3.55 ± 0.08 | 98.59 |
10 g/L | -0.928 | 1.28 ± 0.04 | 148 | -84 | 94.0 | 2.98 ± 0.09 | 82.77 |
Fig. 2. (a) The equivalent circuits used to fit the impedance for A36 CS in (a-1) artificial seawater at first day of exposure, (a-2) artificial seawater after 1day exposure, (a-3) artificial seawater with different concentration of EPS, (b) Nyquist; (c) Bode phase plots and (d) Potentiodynamic polarization curves of A36 CS in artificial seawater without and with different concentration of EPS after 5 days’ exposure at room temperature.
Sample | EIS | ||||||||
---|---|---|---|---|---|---|---|---|---|
Cinh | Exposure time | Rs (Ω cm2) | Rct±SD (Ω cm2) | CPEdl (S sn cm-2) | n | Rfilm±SD (Ω cm2) | CPEfilm (S sn cm-2) | n | P (%) |
First | 1.92 | 851.8 ± 5.67 | 2.9 × 10-4 | 0.89 | - | - | - | - | |
1day | 5.53 | 1052 ± 10.56 | 2.37 × 10-4 | 0.81 | 312.6 ± 1.73 | 9.48 × 10-4 | 0.73 | - | |
2days | 8.92 | 1120 ± 9.26 | 5.53 × 10-4 | 0.76 | 156.8 ± 4.05 | 8.39 × 10-4 | 0.87 | - | |
3days | 6.26 | 1423 ± 16.75 | 3.03 × 10-4 | 0.81 | 7.93 ± 1.96 | 1.14 × 10-4 | 0.69 | - | |
4days | 5.49 | 1765 ± 14.89 | 1.38 × 10-4 | 0.69 | 7.45 ± 0.28 | 1.15 × 10-4 | 0.69 | - | |
5days | 5.54 | 1552 ± 17.29 | 1.54 × 10-4 | 0.68 | 7.47 ± 0.45 | 6.47 × 10-4 | 0.58 | - | |
1 g/L | First | 1.56 | 1221.8 ± 5.79 | 9.75 × 10-4 | 0.76 | 96.66 ± 3.48 | 1.86 × 10-4 | 0.67 | 30.28 |
1day | 2.78 | 1496 ± 2.86 | 2.6 × 10-4 | 0.79 | 105.3 ± 2.50 | 1.86 × 10-4 | 0.58 | 29.68 | |
2days | 3.79 | 1548 ± 5.90 | 2.1 × 10-4 | 0.8 | 155.5 ± 3.61 | 2.02 × 10-4 | 0.83 | 27.64 | |
3days | 2.25 | 1907 ± 3.28 | 1.3 × 10-4 | 0.8 | 135.5 ± 3.06 | 5.82 × 10-5 | 0.83 | 25.38 | |
4days | 5.29 | 2558 ± 1.98 | 1.9 × 10-4 | 0.72 | 99.8 ± 1.69 | 6.87 × 10-5 | 0.75 | 5.6 | |
5days | 6.75 | 1871 ± 1.15 | 2.6 × 10-4 | 0.79 | 61.86 ± 0.93 | 7.98 × 10-5 | 0.85 | 17.04 | |
3 g/L | First | 5.29 | 1325 ± 3.78 | 7.54 × 10-4 | 0.87 | 312.9 ± 1.27 | 6.35 × 10-4 | 0.75 | 39.06 |
1day | 8.29 | 1861 ± 1.04 | 1.81 × 10-4 | 0.85 | 300.7 ± 2.73 | 1.86 × 10-4 | 0.84 | 43.5 | |
2days | 2.33 | 1940 ± 1.65 | 4.4 × 10-4 | 0.87 | 266.4 ± 1.64 | 8.39 × 10-5 | 0.98 | 42.3 | |
3days | 5.28 | 2793 ± 2.09 | 4.1 × 10-4 | 0.89 | 350.5 ± 2.08 | 4.3 × 10-4 | 0.87 | 49.1 | |
4days | 2.64 | 3838 ± 5.69 | 4.7 × 10-4 | 0.83 | 417.4 ± 2.39 | 3.3 × 10-4 | 0.91 | 54.1 | |
5days | 3.87 | 5398 ± 1.41 | 4.5 × 10-4 | 0.8 | 427.1 ± 4.17 | 8.72 × 10-4 | 0.83 | 71.3 | |
5 g/L | First | 8.05 | 1715 ± 1.63 | 5.67 × 10-4 | 0.8 | - | - | - | 46.1 |
1day | 4.8 | 2343 ± 2.05 | 1.32 × 10-4 | 0.77 | 223 ± 0.99 | 2.14 × 10-4 | 0.83 | 55.1 | |
2days | 4.52 | 5336 ± 4.98 | 1.74 × 10-4 | 0.8 | 1735 ± 5.84 | 1.36 × 10-4 | 0.79 | 79.1 | |
3days | 8.65 | 7621 ± 5.81 | 1.36 × 10-4 | 0.77 | 3147 ± 7.69 | 1.59 × 10-4 | 0.89 | 81.3 | |
4days | 9.53 | 7472 ± 3.06 | 2.6 × 10-4 | 0.8 | 2890 ± 4.30 | 1.4 × 10-4 | 0.88 | 76.4 | |
5days | 9.76 | 6951 ± 5.18 | 1.22 × 10-4 | 0.8 | 662.7 ± 2.86 | 2.15 × 10-4 | 0.84 | 77.67 | |
10 g/L | First | 3.5 | 2478 ± 1.30 | 2.29 × 10-4 | 0.8 | 159.5 ± 0.92 | 9.89 × 10-5 | 0.9 | 65.6 |
1day | 6.53 | 3172 ± 1.94 | 4.2 × 10-4 | 0.79 | 189.3 ± 0.81 | 8.89 × 10-6 | 0.8 | 66.8 | |
2days | 7.6 | 5338 ± 3.92 | 3.9 × 10-4 | 0.79 | 262.6 ± 0.35 | 1.35 × 10-5 | 0.8 | 79.01 | |
3days | 8.61 | 8008 ± 4.82 | 3.1 × 10-4 | 0.81 | 817.8 ± 2.78 | 2.22 × 10-4 | 0.8 | 82.2 | |
4days | 3.38 | 12256 ± 7.15 | 3.6 × 10-4 | 0.82 | 390.1 ± 1.69 | 5.12 × 10-4 | 0.9 | 85.6 | |
5days | 10 | 17,260 ± 9.76 | 3.1 × 10-4 | 0.83 | 22.5 ± 0.65 | 2.38 × 10-4 | 0.9 | 91.1 |
Table 2 Electrical elements obtained from the best fitting of experimental impedance diagrams of A36 CS in artificial seawater in the absence and presence of different concentrations of EPS with different exposure times at room temperature.
Sample | EIS | ||||||||
---|---|---|---|---|---|---|---|---|---|
Cinh | Exposure time | Rs (Ω cm2) | Rct±SD (Ω cm2) | CPEdl (S sn cm-2) | n | Rfilm±SD (Ω cm2) | CPEfilm (S sn cm-2) | n | P (%) |
First | 1.92 | 851.8 ± 5.67 | 2.9 × 10-4 | 0.89 | - | - | - | - | |
1day | 5.53 | 1052 ± 10.56 | 2.37 × 10-4 | 0.81 | 312.6 ± 1.73 | 9.48 × 10-4 | 0.73 | - | |
2days | 8.92 | 1120 ± 9.26 | 5.53 × 10-4 | 0.76 | 156.8 ± 4.05 | 8.39 × 10-4 | 0.87 | - | |
3days | 6.26 | 1423 ± 16.75 | 3.03 × 10-4 | 0.81 | 7.93 ± 1.96 | 1.14 × 10-4 | 0.69 | - | |
4days | 5.49 | 1765 ± 14.89 | 1.38 × 10-4 | 0.69 | 7.45 ± 0.28 | 1.15 × 10-4 | 0.69 | - | |
5days | 5.54 | 1552 ± 17.29 | 1.54 × 10-4 | 0.68 | 7.47 ± 0.45 | 6.47 × 10-4 | 0.58 | - | |
1 g/L | First | 1.56 | 1221.8 ± 5.79 | 9.75 × 10-4 | 0.76 | 96.66 ± 3.48 | 1.86 × 10-4 | 0.67 | 30.28 |
1day | 2.78 | 1496 ± 2.86 | 2.6 × 10-4 | 0.79 | 105.3 ± 2.50 | 1.86 × 10-4 | 0.58 | 29.68 | |
2days | 3.79 | 1548 ± 5.90 | 2.1 × 10-4 | 0.8 | 155.5 ± 3.61 | 2.02 × 10-4 | 0.83 | 27.64 | |
3days | 2.25 | 1907 ± 3.28 | 1.3 × 10-4 | 0.8 | 135.5 ± 3.06 | 5.82 × 10-5 | 0.83 | 25.38 | |
4days | 5.29 | 2558 ± 1.98 | 1.9 × 10-4 | 0.72 | 99.8 ± 1.69 | 6.87 × 10-5 | 0.75 | 5.6 | |
5days | 6.75 | 1871 ± 1.15 | 2.6 × 10-4 | 0.79 | 61.86 ± 0.93 | 7.98 × 10-5 | 0.85 | 17.04 | |
3 g/L | First | 5.29 | 1325 ± 3.78 | 7.54 × 10-4 | 0.87 | 312.9 ± 1.27 | 6.35 × 10-4 | 0.75 | 39.06 |
1day | 8.29 | 1861 ± 1.04 | 1.81 × 10-4 | 0.85 | 300.7 ± 2.73 | 1.86 × 10-4 | 0.84 | 43.5 | |
2days | 2.33 | 1940 ± 1.65 | 4.4 × 10-4 | 0.87 | 266.4 ± 1.64 | 8.39 × 10-5 | 0.98 | 42.3 | |
3days | 5.28 | 2793 ± 2.09 | 4.1 × 10-4 | 0.89 | 350.5 ± 2.08 | 4.3 × 10-4 | 0.87 | 49.1 | |
4days | 2.64 | 3838 ± 5.69 | 4.7 × 10-4 | 0.83 | 417.4 ± 2.39 | 3.3 × 10-4 | 0.91 | 54.1 | |
5days | 3.87 | 5398 ± 1.41 | 4.5 × 10-4 | 0.8 | 427.1 ± 4.17 | 8.72 × 10-4 | 0.83 | 71.3 | |
5 g/L | First | 8.05 | 1715 ± 1.63 | 5.67 × 10-4 | 0.8 | - | - | - | 46.1 |
1day | 4.8 | 2343 ± 2.05 | 1.32 × 10-4 | 0.77 | 223 ± 0.99 | 2.14 × 10-4 | 0.83 | 55.1 | |
2days | 4.52 | 5336 ± 4.98 | 1.74 × 10-4 | 0.8 | 1735 ± 5.84 | 1.36 × 10-4 | 0.79 | 79.1 | |
3days | 8.65 | 7621 ± 5.81 | 1.36 × 10-4 | 0.77 | 3147 ± 7.69 | 1.59 × 10-4 | 0.89 | 81.3 | |
4days | 9.53 | 7472 ± 3.06 | 2.6 × 10-4 | 0.8 | 2890 ± 4.30 | 1.4 × 10-4 | 0.88 | 76.4 | |
5days | 9.76 | 6951 ± 5.18 | 1.22 × 10-4 | 0.8 | 662.7 ± 2.86 | 2.15 × 10-4 | 0.84 | 77.67 | |
10 g/L | First | 3.5 | 2478 ± 1.30 | 2.29 × 10-4 | 0.8 | 159.5 ± 0.92 | 9.89 × 10-5 | 0.9 | 65.6 |
1day | 6.53 | 3172 ± 1.94 | 4.2 × 10-4 | 0.79 | 189.3 ± 0.81 | 8.89 × 10-6 | 0.8 | 66.8 | |
2days | 7.6 | 5338 ± 3.92 | 3.9 × 10-4 | 0.79 | 262.6 ± 0.35 | 1.35 × 10-5 | 0.8 | 79.01 | |
3days | 8.61 | 8008 ± 4.82 | 3.1 × 10-4 | 0.81 | 817.8 ± 2.78 | 2.22 × 10-4 | 0.8 | 82.2 | |
4days | 3.38 | 12256 ± 7.15 | 3.6 × 10-4 | 0.82 | 390.1 ± 1.69 | 5.12 × 10-4 | 0.9 | 85.6 | |
5days | 10 | 17,260 ± 9.76 | 3.1 × 10-4 | 0.83 | 22.5 ± 0.65 | 2.38 × 10-4 | 0.9 | 91.1 |
Fig. 4. Nyquist plots (a) and Polarization curves (b) for A36 CS in 1 N H2SO4 in the absence and presence of different concentration of EPS at room temperature, (c) the corresponding equivalent model used to fit EIS data.
Cinh (ppm) | Rs (Ω cm2) | Rct±SD (Ω cm2) | Y0 (S sn cm-2) | n | RL±SD (Ω cm2) | L (H cm2) | P (%) |
---|---|---|---|---|---|---|---|
0 | 1.18 | 19.01 ± 0.63 | 4.5 × 10-4 | 0.89 | 17.02 ± 2.1 | 3.34 | - |
200 | 0.39 | 81.17 ± 4.51 | 3.56 × 10-4 | 0.87 | 784.9 ± 9.45 | 2789 | 76.58 |
400 | 1.39 | 87.35 ± 5.13 | 4.6 × 10-4 | 0.84 | 373.2 ± 8.58 | 7.19 × 104 | 78.23 |
800 | 0.48 | 131.2 ± 3.05 | 2.52 × 10-4 | 0.86 | 325.5 ± 4.93 | 7.21 × 104 | 85.51 |
1000 | 0.36 | 144.3 ± 4.16 | 1.72 × 10-4 | 0.87 | 356.5 ± 3.21 | 7.24 × 104 | 86.82 |
1200 | 0.48 | 44.49 ± 2.08 | 8.86 × 10-4 | 0.83 | 155.8 ± 3.05 | 104.4 | 57.27 |
Table 3 Electrical elements obtained from the best fitting of experimental impedance diagrams of the A36 CS in 1 N H2SO4 in the absence and presence of different concentrations of EPS after 2 h exposure at room temperature.
Cinh (ppm) | Rs (Ω cm2) | Rct±SD (Ω cm2) | Y0 (S sn cm-2) | n | RL±SD (Ω cm2) | L (H cm2) | P (%) |
---|---|---|---|---|---|---|---|
0 | 1.18 | 19.01 ± 0.63 | 4.5 × 10-4 | 0.89 | 17.02 ± 2.1 | 3.34 | - |
200 | 0.39 | 81.17 ± 4.51 | 3.56 × 10-4 | 0.87 | 784.9 ± 9.45 | 2789 | 76.58 |
400 | 1.39 | 87.35 ± 5.13 | 4.6 × 10-4 | 0.84 | 373.2 ± 8.58 | 7.19 × 104 | 78.23 |
800 | 0.48 | 131.2 ± 3.05 | 2.52 × 10-4 | 0.86 | 325.5 ± 4.93 | 7.21 × 104 | 85.51 |
1000 | 0.36 | 144.3 ± 4.16 | 1.72 × 10-4 | 0.87 | 356.5 ± 3.21 | 7.24 × 104 | 86.82 |
1200 | 0.48 | 44.49 ± 2.08 | 8.86 × 10-4 | 0.83 | 155.8 ± 3.05 | 104.4 | 57.27 |
Cinh (ppm) | Tafel extrapolation | Wight loss measurements | |||||
---|---|---|---|---|---|---|---|
Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | Weight loss (mg) | CR (mpy) | |
0 | -485 | 451.8 | 106 | -53 | - | 14.6 | 34,045.41 |
200 | -472 | 107.4 | 100 | -36 | 76.23 | 3.56 | 8301.48 |
400 | -48 | 102 | 115 | -66 | 77.42 | 3.03 | 7065.59 |
800 | -456 | 94.28 | 134 | -41 | 79.13 | 2.56 | 6179.45 |
1000 | -456 | 48.03 | 132 | -41 | 89.37 | 1.14 | 2658.34 |
1200 | -467 | 252.6 | 109 | -63 | 44.09 | 8.43 | 19,657.73 |
Table 4 Fitted results of potentiodynamic polarization measurements and weight loss data of A36 CS in 1 N H2SO4 in the absence and presence of different concentrations of EPS after 2 h exposure at room temperature.
Cinh (ppm) | Tafel extrapolation | Wight loss measurements | |||||
---|---|---|---|---|---|---|---|
Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | Weight loss (mg) | CR (mpy) | |
0 | -485 | 451.8 | 106 | -53 | - | 14.6 | 34,045.41 |
200 | -472 | 107.4 | 100 | -36 | 76.23 | 3.56 | 8301.48 |
400 | -48 | 102 | 115 | -66 | 77.42 | 3.03 | 7065.59 |
800 | -456 | 94.28 | 134 | -41 | 79.13 | 2.56 | 6179.45 |
1000 | -456 | 48.03 | 132 | -41 | 89.37 | 1.14 | 2658.34 |
1200 | -467 | 252.6 | 109 | -63 | 44.09 | 8.43 | 19,657.73 |
EPS production (g/L) | Tafel extrapolation | ||||||
---|---|---|---|---|---|---|---|
Sample | Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | ||
Blank | - | -0.892 | 21.34 ± 1.41 | 91 | -263 | - | |
Carbon sources | Glucose | 1.79 | -0.837 | 1.76 ± 0.07 | 125 | -270 | 91.75 |
Sucrose | 8.45 | -0.820 | 5.46 ± 0.76 | 120 | -220 | 74.41 | |
Fructose | 3.96 | -0.725 | 7.66 ± 0.95 | 113 | -256 | 64.1 | |
Xylose | 4.34 | -0.795 | 3.33 ± 0.23 | 85 | -289 | 84.39 | |
mannitol | 4.01 | -0.850 | 0.614 ± 0.06 | 87 | -278 | 97.1 | |
Galactose | 5.25 | -0.816 | 3.86 ± 0.15 | 115 | -265 | 81.91 | |
Nitrogen sources | Peptone | 4.82 | -0.821 | 2.98 ± 0.09 | 105 | -234 | 86.1 |
Tryptone | 6.16 | -0.755 | 14.2 ± 0.57 | 81 | -249 | 33.5 | |
Yeast | 4.88 | -0.831 | 1.73 ± 0.06 | 126 | -195 | 91.9 | |
NH4Cl | 4.76 | -0.769 | 11.4 ± 0.63 | 90 | -172 | 46.6 | |
(NH4)2SO4 | 14.1 | -0.821 | 1.5 ± 0.02 | 119 | -234 | 92.9 | |
(NH4)2 SO4 Concentration (g/L) | 0.5 | 10.27 | -0.787 | 16.7 ± 0.93 | 79 | -141 | 21.74 |
1 | 14.8 | -0.795 | 6.46 ± 0.26 | 113 | -212 | 95.97 | |
2 | 11.9 | -0.767 | 5.06 ± 0.07 | 56 | -160 | 76.29 | |
4 | 5.38 | -0.652 | 0.31 ± 0.01 | 61 | -69 | 98.54 | |
8 | 2.56 | -0.617 | 3.34 ± 0.04 | 110 | -79 | 84.35 | |
d-Manitol Concentration (g/L) | 10 | 8.81 | -0.798 | 7.54±.0.25 | 85 | -151 | 64.67 |
30 | 14.80 | -0.795 | 2.77 ± 0.12 | 103 | -141 | 94.1 | |
50 | 22.29 | -0.837 | 1.26 ± 0.08 | 95 | -114 | 95.97 | |
70 | 33.80 | -0.815 | 1.57 ± 0.03 | 102 | -82 | 92.64 | |
Time | 1day | 15.74 | -0.849 | 1.84 ± 0.02 | 99 | -136 | 91.38 |
2days | 19.14 | -0.879 | 1.2 ± 0.02 | 103 | -103 | 94.38 | |
3days | 22.29 | -0.837 | 2.77 ± 0.04 | 103 | -141 | 87.02 | |
4days | 18.21 | -0.852 | 2.56 ± 0.52 | 117 | -100 | 88.01 | |
5days | 16.06 | -0.879 | 2.71 ± 0.13 | 78 | -100 | 87.31 | |
7 days | 11.8 | -0.834 | 3.67 ± 0.26 | 93 | -91 | 82.81 | |
10 days | 10.98 | -0.84 | 3.22 ± 0.22 | 135 | -88 | 84.92 | |
pH | 6.5 | 17.35 | -0.916 | 7.43 ± 0.45 | 86 | -129 | 65.18 |
7 | 22.65 | -0.892 | 3.82 ± 0.38 | 115 | -130 | 82.10 | |
7.5 | 22.24 | -0.837 | 2.77 ± 0.09 | 103 | -141 | 87.02 | |
8 | 18.11 | -0.868 | 1.76 ± 0.08 | 70 | -101 | 91.75 | |
8.5 | 17.27 | -0.908 | 4.64 ± 0.38 | 112 | -120 | 78.26 |
Table 5 Effect of different parameters on dried weight of EPS production and corrosion parameters obtained from Tafel extrapolation for corrosion of CS.
EPS production (g/L) | Tafel extrapolation | ||||||
---|---|---|---|---|---|---|---|
Sample | Ecorr (mV vs. SCE) | Icorr±SD (μA cm-2) | βa (mV dec-1) | βc (mV dec-1) | P (%) | ||
Blank | - | -0.892 | 21.34 ± 1.41 | 91 | -263 | - | |
Carbon sources | Glucose | 1.79 | -0.837 | 1.76 ± 0.07 | 125 | -270 | 91.75 |
Sucrose | 8.45 | -0.820 | 5.46 ± 0.76 | 120 | -220 | 74.41 | |
Fructose | 3.96 | -0.725 | 7.66 ± 0.95 | 113 | -256 | 64.1 | |
Xylose | 4.34 | -0.795 | 3.33 ± 0.23 | 85 | -289 | 84.39 | |
mannitol | 4.01 | -0.850 | 0.614 ± 0.06 | 87 | -278 | 97.1 | |
Galactose | 5.25 | -0.816 | 3.86 ± 0.15 | 115 | -265 | 81.91 | |
Nitrogen sources | Peptone | 4.82 | -0.821 | 2.98 ± 0.09 | 105 | -234 | 86.1 |
Tryptone | 6.16 | -0.755 | 14.2 ± 0.57 | 81 | -249 | 33.5 | |
Yeast | 4.88 | -0.831 | 1.73 ± 0.06 | 126 | -195 | 91.9 | |
NH4Cl | 4.76 | -0.769 | 11.4 ± 0.63 | 90 | -172 | 46.6 | |
(NH4)2SO4 | 14.1 | -0.821 | 1.5 ± 0.02 | 119 | -234 | 92.9 | |
(NH4)2 SO4 Concentration (g/L) | 0.5 | 10.27 | -0.787 | 16.7 ± 0.93 | 79 | -141 | 21.74 |
1 | 14.8 | -0.795 | 6.46 ± 0.26 | 113 | -212 | 95.97 | |
2 | 11.9 | -0.767 | 5.06 ± 0.07 | 56 | -160 | 76.29 | |
4 | 5.38 | -0.652 | 0.31 ± 0.01 | 61 | -69 | 98.54 | |
8 | 2.56 | -0.617 | 3.34 ± 0.04 | 110 | -79 | 84.35 | |
d-Manitol Concentration (g/L) | 10 | 8.81 | -0.798 | 7.54±.0.25 | 85 | -151 | 64.67 |
30 | 14.80 | -0.795 | 2.77 ± 0.12 | 103 | -141 | 94.1 | |
50 | 22.29 | -0.837 | 1.26 ± 0.08 | 95 | -114 | 95.97 | |
70 | 33.80 | -0.815 | 1.57 ± 0.03 | 102 | -82 | 92.64 | |
Time | 1day | 15.74 | -0.849 | 1.84 ± 0.02 | 99 | -136 | 91.38 |
2days | 19.14 | -0.879 | 1.2 ± 0.02 | 103 | -103 | 94.38 | |
3days | 22.29 | -0.837 | 2.77 ± 0.04 | 103 | -141 | 87.02 | |
4days | 18.21 | -0.852 | 2.56 ± 0.52 | 117 | -100 | 88.01 | |
5days | 16.06 | -0.879 | 2.71 ± 0.13 | 78 | -100 | 87.31 | |
7 days | 11.8 | -0.834 | 3.67 ± 0.26 | 93 | -91 | 82.81 | |
10 days | 10.98 | -0.84 | 3.22 ± 0.22 | 135 | -88 | 84.92 | |
pH | 6.5 | 17.35 | -0.916 | 7.43 ± 0.45 | 86 | -129 | 65.18 |
7 | 22.65 | -0.892 | 3.82 ± 0.38 | 115 | -130 | 82.10 | |
7.5 | 22.24 | -0.837 | 2.77 ± 0.09 | 103 | -141 | 87.02 | |
8 | 18.11 | -0.868 | 1.76 ± 0.08 | 70 | -101 | 91.75 | |
8.5 | 17.27 | -0.908 | 4.64 ± 0.38 | 112 | -120 | 78.26 |
Fig. 7. Comparison of the protein and carbohydrate amount of EPS from different culture media. All EPS were prepared after 3 days’ incubation in shaker incubator at 130 rpm rate at 30 °C.
Fig. 8. Structure of N-acetyl hexosamine-iron complex. Oxygen molecule of C-3 hydroxyl and ring oxygen of N-acetyl hexosamine are participating in complexation.
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