Cell disruption technique - grinding with sand

 

 Aim

To demonstrate the breaking up of cell structures using abrasives like sand particles.

Principle

 In order to release microbial cell contents during downstream processing, a number of methods can be used for cell disruption to disintegrate the extremely tough cell walls. Any potential method of disruption must ensure that liable materials are not denatured by the process or hydrolyzed by enzymes present in the cell. The use of combination of different techniques release products from specific locations within yeast cell. Although many techniques are available which are satisfactory at laboratory scale, only limited number have been proved to be suitable for large-scale applications, particularly for intracellular enzyme extraction. Types of cell disruption methods are physical, mechanical and chemical.

Grinding with sand is a mechanical cell disruption method used to break microbial, plant, or animal cells to release intracellular components such as enzymes, proteins, nucleic acids, pigments etc. This technique tears up the structures of a cell using abrasive sand particles. Abrasion and shear force produced by grinding cells with fine sand particles mechanically rupture the cell wall and cell membrane. This helps to achieve the release of cytosolic contents, and allows some degree of breakup of physical structures. Physical structures are further removed by isopycnic centrifugation.

Grinding with sand is commonly used for laboratory-scale extraction from microorganisms and plant tissues. Usually, the process is carried out at low temperature to prevent denaturation of cellular components.

 

Materials Required

1.Yeast culture

2.Mortar and pestle

3.Sterile fine Sand

4. Sabouraud's dextrose Agar

5. Routine microbiological facilities

 

 

Procedure

1. Five ml of yeast suspension was taken into sterile test tube. One test tube was kept as control.

2. The yeast suspension was taken in a sterile mortar, and cloth filtered fine sand was added to it.

3. It was then ground with pestle several times and serially diluted.

4. 1 ml of suspension from 10 ^-4 and 10^-5 dilutions were plated on Sabouraud's dextrose agar and 

    CFU was counted

5.1 ml of the suspension from the control tube was also serially diluted and CFU was counted.

 

Result

Sabouraud's dextrose Agar plated with the sample ground with sand particle showed a fall in colony count, which indicate fall in cell count. 

 

Conclusion

Grinding with sand is a mechanical cell disruption technique in which the abrasive action of sand particles breaks the cell wall and membrane, releasing intracellular materials.