If the pH is too high or too low, the enzyme activity will significantly decrease Excessive acidity or alkalinity can denature and inactivate the enzyme itself Changes in pH can affect the dissociation of relevant functional groups on the active site of enzyme molecules. At the optimal pH, the dissociation state of the active group on the enzyme molecule is most suitable for binding to the substrate. When the pH is higher or lower than the optimal pH, the dissociation state of the active group changes and the binding force between the enzyme and the substrate decreases.

The effect of pH on enzyme activity

Both too low (too acidic) and too high (too alkaline) pH can cause enzyme proteins to denature and become inactive. The change in pH can affect the degree of dissociation of essential functional groups on the enzyme active center, as well as the degree of dissociation of substrates and coenzymes, thereby affecting the binding and catalysis of enzyme molecules to substrate molecules.

Only at a specific pH, the dissociation state of enzymes, substrates, and coenzymes is most suitable for their mutual binding and catalytic activity, thereby maximizing the enzyme reaction rate.

The rate of enzyme conversion can be expressed as the decrease in substrate or increase in product per unit volume per unit time. The determination of enzyme activity can be done by quantitatively measuring the changes in the quantity of products or substrates produced by the enzyme reaction over time, or by quantitatively measuring changes in a certain property of the enzyme reaction substrate, such as viscosity changes. Enzyme activity is usually measured at the optimal pH and ionic strength of the enzyme, as well as at a specified temperature.

So how do we control the pH value;

Our laboratory users usually use the SC-200A pH automatic control liquid addition system

[Instrument Overview]

The SC-200A pH automatic control liquid addition system (dual pump) is a new type of automated control equipment that integrates real-time online or static pH control, measurement, and automatic acid and alkali addition adjustment. High pH accuracy and good stability. Widely used in universities, research institutes, laboratories, pilot workshops, industrial production processes for the preparation of specific pH solutions, and other places where pH values need to be detected, controlled, and adjusted in production processes.

[Scope of Application]

◆ Laboratories of higher education institutions and research institutes: Preparation of specific pH solutions for tissue culture and automatic pH titration.

Pharmaceutical, biochemical, chemical, spraying, and electroplating factories: pH adjustment and control of liquid addition in reactors, reaction tanks, reaction kettles, and solution tanks.

◆ Bioengineering reactors and food fermentation factories: preparation of pH buffer solution and control of cultivation process adjustment.

◆ Plant Extract Workshop: Acid base washing regulation and control of ion exchange columns.

◆ Hospital analysis room: adjust and control pH value during preparation and inspection.

Environmental protection power generation, circulating water, tap water purification, pH control in industrial wastewater and municipal sewage treatment processes.

[Technical Parameters]

1. Working power supply: AC220V ± 10%, 50Hz

2. Control range: 0-14 pH

3. Measurement accuracy: ± 0.05 pH

4. Resolution: 0.01 pH

5. Pump head speed: 0.1-300 revolutions per minute infinite speed regulation

6. Speed display: OLED high-definition LCD window display

7. Liquid addition rate: 0.12-190ml/min (tap water)

8. Liquid filling pump head: dual pump

9. Measuring electrode: pH triple composite electrode or glass electrode

10. Temperature compensation: Automatic temperature compensation (PT1000)

11. PH controller: high-precision intelligent controller

12. PH electrode suitable temperature: 0-80 ℃

13. PH standard solution: 6.86/4.00

14. Dimensions: 480 * 320 * 220mm

15. Environmental temperature: Room temperature~40 ℃ Relative humidity:<80%

16. Whole machine weight: approximately 14kg

[Control Method]

Control mode: automatic, manual, stop

A: Automatic mode: The instrument will automatically start/stop adding acid (alkali) and adjust the pH value to the set range based on the real-time detected pH value and the set value.

B: Manual mode: not controlled by the pH controller, continuously rotating, manually starting/stopping acid (alkali) addition, adjusting the pH value to the set range. It can also be used for quick adjustment, or to drive away bubbles inside the tube, or for the transportation of other liquids

C: Stop: Stop the liquid addition action, but the pH value is detected and displayed in real-time; Used for standby or adjustment purposes, it can also be used as an online pH measurement display terminal.

[Performance Characteristics]

◆ High precision intelligent pH controller, with a large LCD screen displaying dynamic pH and temperature values in real-time, and an alarm for exceeding the range.

◆ Multiple control measurement modes: automatic, manual, stop, can be freely switched, achieving multiple uses for one machine.

Single pump for adding acid or alkali, suitable for using only one liquid (acid or alkali) to adjust and control the pH value.

◆ Adopting OLED high-definition LCD window, it displays the current motor speed and working status separately, and the liquid addition rate can be infinitely adjusted.

The upper and lower limits of pH value can be freely set, and the set value and measured value are displayed simultaneously.

The pH electrode can be calibrated at one or two points, and the pH value and temperature can be automatically measured. The pH value can be automatically calibrated according to temperature.

◆ Adopting a stepper motor to control the peristaltic pump for liquid addition, the liquid contacts the inlet pump tube without touching the pump body, resulting in no pollution.

◆ Choosing different forms of pH precision composite electrodes, as well as electrode sheaths and extension rods made of PTFE material, can be used to monitor and adjust pH values in special containers at high temperatures, reaction vessels, and reactors.