What is the Difference Between Agar and Noble Agar

The main difference between agar and noble agar is that agar is a jelly-like substance that consists of polysaccharides obtained from some species of red algae whereas noble agar is a bleached and washed derivative of agar that results in white agar.

Agar and noble agar are two types of agar that provide essential nutrients for the growth of bacteria. Both are solidifying agents.  

Key Areas Covered

1. What is Agar
      – Definition, Features, Importance
2. What is Noble Agar
     – Definition, Features, Importance
3. Similarities Between Agar and Noble Agar
     – Outline of Common Features
4. Difference Between Agar and Noble Agar
     – Comparison of Key Differences

Key Terms

Agar, Noble AgarAgar vs Noble Agar - Comparison Summary

What is Agar

Agar or agar-agar is a gelatin-like product manufactured from different types of red algae, including Gracilaria and Gelidium. Due to its gelatinous properties, it is important as a component in the preparation of growth media for culturing bacteria and fungi, mainly for scientific and medicinal research. The basis of the agar polymer is galactose, which is a derivative of the polysaccharide agarose. Generally, agarose is also a gelatine-like food that is important for vegans, substituting meat. It was first found in the late 1650s by Mino Tarōzaemon in Japan.

Compare Agar and Noble Agar

Figure 1: Agar

Furthermore, agar serves as the supporting structure of the cell walls of certain species of algae, and it can be released after boiling. The term “agar” comes from the Malay/Indonesian name for red algae from which the jelly is produced. It is also a food ingredient mainly used in traditional Malay and Japanese desserts. Other terms for agar are Kanten, Japanese isinglass, Ceylon moss, or Jaffna moss. Agal-agal or Ceylon agar is generally derived from Gracilaria lichenoides. In addition, the other important feature of agar is its use in culture media as a solid substrate for microbial work.

What is Noble Agar

Noble agar is the type of agar that has the highest purity. More importantly, the methods involved in the removal of trace impurities include the Noble and the Tonney methods. These methods remove ash and minerals as well. In general, these impurities interfere with many sensitive applications, including immunological methods and electrophoresis. Noble agar is a homogenous mixture that is a free-flowing powder. The color of the Noble agar is white to light tan.

Agar vs Noble Agar

Figure 2: Noble Agar

Moreover, Noble agar acts as the solid support material to culture tumor spheroids in the lysoplate assay method of Osserman and Lawlor to measure the concentration of lysozyme in albumin and plasma and in BG11 media component. Furthermore, the structure of the Noble agar contains repeating units of D-galactose and 3,6-anhydro-L-galactose. In addition, the key components of the agar include agarose and agaropectin. Noble agar also serves as a human and animal food supplement.  

Similarities Between Agar and Noble Agar

  • Agar and Noble agar are two types of solidifying agents that are important for bacterial growth.
  • They provide essential nutrients for the growth of bacteria.
  • Moreover, they are gelatinous substances obtained from seaweeds.

Difference Between Agar and Noble Agar


Agar refers to a gelatinous substance obtained from certain red seaweeds and used in biological culture media and as a thickener in foods, while Noble agar refers to a gelling hydrocolloid extracted from seaweeds such as Gelidium and Gracilaria.


Agar is obtained from red algae, while Noble agar is a bleached and washed derivative of agar, resulting in a white gel.


Moreover, agar is a solidifying agent, while noble agar is also a solidifying agent that is essentially free of impurities.  


In brief, agar and Noble agar are two solidifying agents important for bacterial growth. Moreover, they provide essential nutrients for the growth of bacteria. Generally, red algae are the source of agar. Agar serves as a solidifying agent. In comparison, Noble agar is a bleached and washed derivative of agar. However, this process results in whitish agar that is free of impurities. Therefore, the main difference between agar and Noble agar is the purity of agar.                                                    

  1. Agar. Encyclopædia Britannica.  
  2. Noble Agar. Scientific Laboratory Supplies Ltd. ©
Image Courtesy:
  1. GreenTeaYokan” By Sjschen – Own work (CC BY-SA 4.0) via Commons Wikimedia
  2. Colture of Planktothrix rubescens in BG – 11 medium” By Vincenzo Damiano – Own Work (CC BY-SA 4.0) via Commons Wikimedia

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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