nutrient agar (ready to use media)

Explore the Array of Bacteria Thriving on Nutrient Agar

Published: 11th Jul 2023, 16:09

The realm of microbiology beckons with a captivating assortment of agars tailored to foster the growth of various bacteria. Amongst these, nutrient agar stands out as a widely employed medium capable of supporting the growth of an extensive range of bacterial species. Although primarily designed for non-fastidious bacteria, nutrient agar also accommodates the cultivation of fungi and other microorganisms. Its versatility makes it a go-to choice in microbiological laboratories, facilitating demonstrations, teaching endeavours, and purity checks before further biochemical or serological testing. This article aims to delve into the diverse array of bacteria that grow on nutrient agar medium.

Unravelling Nutrient Agar

Nutrient agar serves as a general-purpose medium, providing an optimal environment for the proliferation of various microorganisms. Composed of peptone, beef extract, yeast extract, and agar, this medium furnishes the essential nitrogen compounds, carbon, vitamins, and trace elements vital for bacterial growth. Sodium chloride, a key ingredient, preserves the osmotic balance within the medium, while agar acts as a solid foundation, facilitating microbial colonization.

Preparing Nutrient Agar

To prepare nutrient agar, distilled water, beef extract, peptone, sodium chloride, and agar are required. TM Media offers meticulously composed Dehydrated Nutrient Culture Media that ensures the desired consistency.

Step-by-Step Guide to Utilizing TM Media Nutrient Media

  1. Dissolve 28 grams of dehydrated nutrient media in 1000 mL of purified or distilled water.
  2. Boil the medium to ensure complete dissolution.
  3. Sterilize the medium by autoclaving at 15 psi pressure and 121°C for 15 minutes.
  4. After autoclaving, allow the medium to cool down to 45–50°C.
  5. Optionally, enrich the medium with 5–10% blood or other biological fluids.
  6. Thoroughly mix the medium and pour it into sterile petri dishes.
  7. Inoculate the desired sample onto the culture medium.
  8. Incubate the petri dishes at 35–37°C for 24 hours.

Cultural Characteristics of Different Microorganisms on Nutrient Agar



Inoculum (CFU/ml)


Salmonella typhi



Good luxuriant

Streptococcus pyogenes



Good luxuriant

Yersinia enterocolitica



Good luxuriant

Staphylococcus aureus



Good luxuriant

Escherichia coli



Good luxuriant

Pseudomonas aeruginosa



Good luxuriant

Salmonella enteritidis



Good luxuriant

Utilizing Nutrient Agar

Nutrient agar can accommodate the growth of bacteria through different approaches, including plate cultures, slant cultures, and liquid cultures.

  • Plate Cultures: The most common method involves pouring sterilized nutrient media into petri plates and subsequently inoculating the desired microorganisms. The plates are then incubated at the appropriate temperature.
  • Slant Cultures: In this method, a sterilized test tube is employed. The molten nutrient media is added to the test tube, allowing it to solidify. The desired microorganisms are then inoculated, followed by incubation at the appropriate temperature.
  • Liquid Cultures: Although less frequent, liquid cultures devoid of agar can be utilized. The nutrient media is added to a flask, and the desired microorganisms are inoculated. Subsequently, the cultures are incubated at the appropriate temperature.

Advantages of Nutrient Agar

Nutrient agar offers several advantages that contribute to its widespread usage. Notably, its rich nutrient composition accelerates bacterial growth. Moreover, nutrient agar is a cost-effective medium, making it an attractive choice for various applications in microbiology.


The enigmatic world of microbiology unravels its secrets on nutrient agar, a versatile medium accommodating a diverse spectrum of bacterial growth. With its formulation and nutrient-rich composition, nutrient agar provides an ideal platform for the thriving and observation of non-fastidious bacteria, fungi, and other microorganisms. From its preparation to the cultural characteristics exhibited by various bacteria, nutrient agar remains a cornerstone in microbiological laboratories worldwide, fueling scientific discoveries and fostering our understanding of the microbial world.

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