#culture_media_hindi #culture_media_microbiology #classification_of_culture_media #microbiology #microbiology_lecture
What is definition of culture media
What is introduction of culture media
Classification of culture media
Use of culture
Culture media in hindi
Solid culture media
Liquid culture media
Semi solid culture media
Transfer culture media
Selective culture media
Anaerobic culture media
What is agar agar
What is agar
CLAD agar
Nutrient Agar
What is bacteria growth
What Is Culture Media?
Culture media are mediums that provide essential nutrients and minerals to support the growth of microorganisms in the laboratory.
Microorganisms have varying nature, characteristics, habitat, and even nutritional requirements, thus it is impossible to culture them with one type of culture media. However, there are also microorganisms that can’t grow on a culture media at all in any condition - these are called obligate parasites.[1]
Culturing microorganisms is essential for diagnosing infectious diseases, obtaining antigens, developing serological assays for vaccines, genetic studies, and identification of microbial species.[1]
Furthermore, it’s also essential for isolating pure cultures, storing culture stock, studying biochemical reactions, testing microbial contamination, checking antimicrobial agents and preservatives effect, testing viable count, and testing antibiotic sensitivity.[2]
This article will focus on the composition, classification, and types of culture media used in microbiology labs to study a spectrum of microbial forms.
Classification and Types of Culture Media
Growing microorganisms in the lab involve mimicking the organisms’ natural habitat or environment, and this is possible in the laboratory by formulating culture media that meets their requirements. Therefore, many culture media were developed by scientists according to the microbial species to be cultured.
The basic media contains a source of carbon & energy, nitrogen source, growth factors, and some trace elements.[1] Some commonly used media components include peptone, agar, water, casein hydrolysate, malt extract, meat extract, and yeast extract. In addition, the pH of the medium should be set accordingly.[3]
However, some additional components or nutrients are added to the media when growing specific microorganisms.
Culture media can be classified in three ways: based on their consistency, nutritional component, and applications.[1]
Classification of culture media based on consistency
Solid media: In these media, the agar which is an unbranched long chain of polysaccharides is added in the concentration of 1.5-2.0%. Most commonly, 1.3% agar is used to prepare solid media in labs. The agar-containing media solidifies at 37 ºC.[1]
Sometimes, in the place of agar, some other inert solidifying agents are used, such as gellan gum.
Solid media are used to grow microorganisms in their full physical form, prepare bacterial pure cultures, or isolate bacteria to study colony characteristics.[1]
The bacterial growth on solid media varies in appearance as mucoid, round, smooth, rough, filamentous, irregular, and punctiform.
The media is not hydrolyzed by microorganisms and is free from growth-inhibiting substances.[3] Examples of solid media are blood agar, nutrient agar, McConkey agar, and chocolate agar.
Semisolid media: This media has 0.2-0.5% agar concentration, and due to the reduced agar concentration, it appears as a soft, jelly-like substance.
It’s mainly used to study the motility of microorganisms, distinguish between motile and non-motile bacterial strains (through U-tube and Cragie’s tube), and cultivate microaerophilic bacteria - bacteria on this media appear as a thick line.
Examples of semi-solid media are: Hugh and Leifson’s oxidation fermentation medium, Stuart’s and Amies media, and Mannitol motility media.[1]
Liquid media: These media do not contain any traces of solidifying agents, such as agar or gelatin, and large growth of bacterial colonies can be observed in the media. Liquid media are also called broths, they allow for uniform and turbid growth of bacterial strains when incubated at 37ºC for 24hrs.
The media is used for the profuse growth of microorganisms and fermentation studies. Examples include Tryptic soy broth, phenol red carbohydrate broth, MR-VP broth, and nutrient broth.
Classification based on the nutritional component
Simple media: It’s a general-purpose media that supports the growth of non-fastidious microbes, and it is primarily ush, peptone water, and nutrient agar.
Complex media: These are media containing Dox Medium.[1]
C. Classification of culture media based o.
The basal media do not require enr Enterobacteriaceae.[1]
Tor in sub-culturing processes. Examples are nutrient broth, nutrient agar, and peptone water.
Enriched media: This .
Examples are chocolate agar, blood agar, and Loeffler’s serum slope. Chocolate media is used to grow N. gonorrhea while b]
Selective media: This media