RAW MATERIAL USED FOR PREPARATION OF CULTURE MEDIA

RAW MATERIAL USED FOR CULTURE MEDIA (BACTERIOLOGICAL MEDIA)

CULTURE MEDIA: - Microbiological media, or bacterial culture media is a growth medium used to grow bacteria. In other words, bacteriological media are an artificially prepared mixture of various nutrients for the growth and multiplication of micro-organism.

Bacterial culture media is used when a specific bacterium must be grown in order to confirm the presence of an infection or study a specific bacterium further. There are thousands of different media used today.

Most Common raw materials or ingredients used in culture media are as follows…..

1. Water

2. Peptone

3. Beef extract

4. Yeast extract

5. Meat extract

6. Solidifying agents

7. Buffering agents

8. Other components

1. WATER AS SOLVENT: -

Water plays a vital role in preparation of culture media. For the preparation of culture media tap water, pure water or distilled water may be used by dissolving various organic and inorganic compounds. . All enzymatically controlled chemical reactions occur within the cell in the presence of water. Water should be free from copper ion because copper ion inhibits the growth of micro-organisms. The conductivity of the water should be less than 15 microsiemens.

2. PEPTONE: -

It is a complex mixture of partially digested proteins obtained from lean meat, heart muscle, casein, fibrin, soya meal etc. The important constituents are proteases, amino acids, inorganic salts which include phosphates, potassium and magnesium and growth factors including nicotinic acid and riboflavin. Peptones mainly supply nitrogenous material and also act as a buffer. Peptone is stored in a tightly closed container because it is hygroscopic and becomes sticky when exposed to air.

3. BEEF EXTRACT: -

Beef Extract is derived from infusion of beef and provides an undefined source of nutrients. Beef Extract is a mixture of peptides and amino acids, nucleotide fractions, organic acids, minerals, and some vitamins. It complements the nutritive properties of peptone by contributing minerals, phosphates, energy sources, and those essential factors missing from peptone.

Beef Extract is frequently used at a concentration of 0.3 to 1.0% in culture media, although concentrations may vary depending on the nutritional requirements for the medium formulation.

4. YEAST EXTRACT:-

Yeast extract is prepared from washed cells of baker's yeast or Saccharomyces. Yeast extract contains wide range of carbohydrates, amino acids, growth factors (vitamin B group) and inorganic salts. Yeast extract is used mainly as a source of vitamins and may be substituted for meat extract.

5. MEAT EXTRACT:-

Meat extract is obtained by hot water extraction of fresh lean beef/meat and then concentrated by evaporation. It contains gelatin, albumoses, peptones, proteoses, amino acids, creatine, creatinine, purines, mineral salts, carbohydrates and growth factors includes thiamine, nicotinic acid, riboflavin, pyridoxine and pantothenic acid etc.

6. SOLIDIFYING AGENT:- (GELLING AGENT)

There are various types of solidifying agents such as gelatin, carrageenanas, alginates, polyaccrylamides are used to solidify culture media but the most important gel forming substance used in culture media is agar.

Agar: Agar is a long chain polysaccharide obtained from seaweeds algae. Agar is a mixture of two polysaccharides such as aggarose (70%) and agaropectin (30%). It also contains calcium, chloride, magnesium, sulphate, iron etc. Agar has the following properties...

· It acts as good solidifying agent (2%).

· It has no nutritional value in media.

· It is bacteriologically inert.

· Resistant to the action of all microorganisms.

· It is stable or firm at different temperatures used for incubation.

· It melts at 95 to 98°C and remains liquid upto 40 to 42°C.

· It gets solidified below 40°C.

· Easily available and economical.

7. BUFFERING AGENTS:-

The optimum ph of the culture medium is also important for growth of desired micro-organism. The use of buffer compounds at specific pk values is especially necessary when fermentable carbohydrates are added as energy source. Such example of buffering agents is phosphates, acetates, citrates, sodium chloride, & specific amino acids that added to culture media.

8. OTHER COMPONENTS:-

Many other substances are added to culture media for specific purposes like growth factors for fastidious organisms, Ph reducing compounds for anaerobic organisms (thioglycollate and cysteine) whole blood to detect hemolytic enzymes etc.

CLICK BELOW TOPIC TO READ

1. INTRODUCTION OF MICROBIOLOGY

2. BRANCHES OF MICROBIOLOGY

3. SCOPE OF MICROBIOLOGY

4. HISTORY OF MICROBIOLOGY {PART 1}

5. HISTORY OF MICROBIOLOGY {PART 2}

6. HISTORY OF MICROBIOLOGY {PART 3}

7. PROKARYOTES VS EUKARYOTES DIFFERENCES

8. MORPHOLOGY OF BACTERIA

9. ULTRASTRUCTURE OF BACTERIA

1. NUTRITIONAL REQUIREMENTS OF BACTERIA

1. RAW MATERIAL USED FOR CULTURE MEDIA