21 Oct 2020

Agar vs. Gelatin

Jessica Rosslee

Table of Contents

Agar and gelatin have similar uses throughout the world and throughout industries, both in cooking and in plant media. When looking at agar and gelatin, most people are curious to know what the main difference is between the two.

The main difference is their sourcing. Agar is a plant derivative, while gelatin is derived from animals. Therefore, agar has been employed as a vegetarian substitute in place of gelatin. Gelatin is a more widely known substance. However, you may be surprised to know that agar has even more potent bonding properties than its animal-derived counterpart.

In order to properly understand the differences between the two, let's take an in-depth look at each of them:

Short Review of Gelatin:

Colorless
Odorless
Derived from the skin and bones of deceased animals
Popularly used in photography, ammunition, cosmetics, desserts and baking
Can be purchased in powder or sheet form
Has several different names when used in an industrial setting
Needs to be dissolved in warm water and then left to set

Short Review of Agar:

Originates from seaweed
Employed in the use of biological testing
Used as an impression substance in dentistry
Useful as a laxative in electrochemistry
Also used in many Japanese desserts
Can be purchased in agar powder form as well as strips
Name is derived from the Malay agar-agar word meaning jelly
Also be known as China grass, Kanten, Japanese isinglass
Begins to set after it has been brought to a boil

Source of Agar

Most people are under the impression that gelatin is made from the hooves and horns of animals. However, it is actually derived from the collagen found in cattle and pig bones, the skin of a pig, or the hides from split cattle. Agar, on the other hand, is made from red algae.

Agar as a Growth Medium

One of the most significant distinctions between agar and gelatin as a growth medium is that agar is not degraded or eaten by bacteria. Agar is also a more robust and firmer substance, so it makes for a superior growth medium.

When it is used for culturing media, the final concentration needs to be approximately 1-2%.

When it is used in motility studies, the final concentration should not exceed 0.5%.

When agar is used for the growth of anaerobes and microaerophiles, it should be used in the final concentration of 0.1%.

If you are using bacteriological grade agar, it would be best to observe the following specifications:

Good clarity
Controlled melting temperature and controlled gelling/solidifying temperature
Proper diffusion characteristics
Zero toxic bacterial inhibitors

The Best Agar for Tissue Culture

Whether you are a student doing a DIY Tissue Culture at home or a scientist looking for agar to add to your tissue culture toolbox, the best agar is just a click away. PCT Supreme Grade agar is your the most affordable high-quality agar on the market and should be used at a rate of 6 – 12 g/L medium. This agar will prove to be an excellent media for tissue culture, whether you are looking to grow in vitro cannabis plants for your home grow or on an industrial scale.

Okay, let's talk specifics now; what are the properties of each substance?

The melting points are distinctly different for each substance. The melting point for agar is 85 degrees Celsius whereas the melting point for gelatin is 35 degrees Celsius. Therefore, agar requires boiling before it sets at 32 – 40 degrees. The setting and gelling for gelatin will occur at lower temperatures but will be influenced by the amount of time and concentration.

Form and Shape

The physical attributes of each substance are similar. Gelatin is translucent, colorless, odorless, and comes either in powder or in sheet form. Agar is also a white translucent product that is available in powder or strip form.

Nutrition

Even though you are reading this to find out about using agar in tissue culture, it is helpful to be familiar with the nutritional properties of both substances and how they compare.