Difference between revisions of "Part:BBa K1675008"
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| − | L-Lactic acid, one of the most important chiral molecules and organic acids, is produced via pyruvate from carbohydrates in diverse microorganisms catalyzed by an NAD-dependent L-lactate dehydrogenase. The ''LdhA'' gene is used in the synthesis of lactic acid. This gene encodes an | + | This device is part of our basic regulation circuit in 2015 project of BIT-China. |
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| + | L-Lactic acid, one of the most important chiral molecules and organic acids, is produced via pyruvate from carbohydrates in diverse microorganisms catalyzed by an NAD-dependent L-lactate dehydrogenase. The ''LdhA'' gene is used in the synthesis of lactic acid. This gene encodes an lactate dehydrogenase (LDH) which converts pyruvate to L-lactate. | ||
To verified the'' LdhA'' gene, we constructed our gene into pET28a (Fig.1), and induced its over-expression by IPTG (Isopropyl β-D-1-Thiogalactopyranoside) under 16 ℃ in BL21(DE)3. | To verified the'' LdhA'' gene, we constructed our gene into pET28a (Fig.1), and induced its over-expression by IPTG (Isopropyl β-D-1-Thiogalactopyranoside) under 16 ℃ in BL21(DE)3. | ||
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According to the Table.1, we could easily found that there is an obvious difference between experimental group and control. Under the anaerobic condition, L-lactate dehydrogenase, coding by LdhA, acts much better ability than under aerobic condition. However, the final pH value of culture fluid is bigger than pKa of lactic acid. We suppose that the bacteria take advantage of lactic acid, due to the lack of carbon source. | According to the Table.1, we could easily found that there is an obvious difference between experimental group and control. Under the anaerobic condition, L-lactate dehydrogenase, coding by LdhA, acts much better ability than under aerobic condition. However, the final pH value of culture fluid is bigger than pKa of lactic acid. We suppose that the bacteria take advantage of lactic acid, due to the lack of carbon source. | ||
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| + | When the initial state of fermentation is under the acidic stress, the regulation capacity of test group is higherthan the control group. (Shown in Fig.2 and Fig.3) | ||
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| + | [[File:fermentation_1.png]] | ||
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| + | Fig.2 The final fermentation result of the basic regulation system under acidic stress. By calculating the pH change of unit active biomass in unit time, This figure can be drawed. | ||
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| + | [[File:fermentation_2.png]] | ||
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| + | Fig.3 The growth curve of E.coli with basic regulation circuit under acidic stress. | ||
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| + | When the initial state is under the alkaline stress, the response of the test group is quicker than the control group, and the capacity is a littlie higer than the control group. (Shown in Fig.4 and Fig.5) | ||
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| + | [[File:fermentation_3.png]] | ||
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| + | Fig.4 The final fermentation result of the basic regulation system under alkaline stress. By calculating the pH change of unit active biomass in unit time, This figure can be drawed. | ||
| + | |||
| + | [[File:fermentation_4.png]] | ||
| + | |||
| + | Fig.5 The growth curve of E.coli with basic regulation circuit under alkaline stress. | ||
| + | |||
<!-- Add more about the biology of this part here | <!-- Add more about the biology of this part here | ||
Latest revision as of 23:35, 27 September 2015
A device used in the synthesis of lactic acid
This device is part of our basic regulation circuit in 2015 project of BIT-China.
L-Lactic acid, one of the most important chiral molecules and organic acids, is produced via pyruvate from carbohydrates in diverse microorganisms catalyzed by an NAD-dependent L-lactate dehydrogenase. The LdhA gene is used in the synthesis of lactic acid. This gene encodes an lactate dehydrogenase (LDH) which converts pyruvate to L-lactate.
To verified the LdhA gene, we constructed our gene into pET28a (Fig.1), and induced its over-expression by IPTG (Isopropyl β-D-1-Thiogalactopyranoside) under 16 ℃ in BL21(DE)3.
Fig.1 The constructed result of LdhA-pET28a
Meanwhile, we put glucose as the substrate of glycolysis (40% glucose solution, add 2ml to 48ml culture solution). After 12 hours fermentation, we measured the pH of the culture fluid. We use the pET28a(BL21(DE3)) as the control. We repeated this process three times and our result is shown in Table.1.
According to the Table.1, we could easily found that there is an obvious difference between experimental group and control. Under the anaerobic condition, L-lactate dehydrogenase, coding by LdhA, acts much better ability than under aerobic condition. However, the final pH value of culture fluid is bigger than pKa of lactic acid. We suppose that the bacteria take advantage of lactic acid, due to the lack of carbon source.
When the initial state of fermentation is under the acidic stress, the regulation capacity of test group is higherthan the control group. (Shown in Fig.2 and Fig.3)
Fig.2 The final fermentation result of the basic regulation system under acidic stress. By calculating the pH change of unit active biomass in unit time, This figure can be drawed.
Fig.3 The growth curve of E.coli with basic regulation circuit under acidic stress.
When the initial state is under the alkaline stress, the response of the test group is quicker than the control group, and the capacity is a littlie higer than the control group. (Shown in Fig.4 and Fig.5)
Fig.4 The final fermentation result of the basic regulation system under alkaline stress. By calculating the pH change of unit active biomass in unit time, This figure can be drawed.
Fig.5 The growth curve of E.coli with basic regulation circuit under alkaline stress.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]