Extraction of Agar from Gracilaria a Red alga II MICROBIOLOGY II TISSUE CULTURE

Summary

In this video, a PhD student demonstrates the process of extracting agar from Gracilaria, a red algae commonly found in seawater. The procedure includes cutting the algae into small fragments, treating it with sodium hydroxide and sulfuric acid, and incubating it at boiling temperatures. After several washing and boiling steps, the solution is filtered and allowed to solidify. The result is pure agar, which is widely used in research and industry. The video provides a step-by-step guide on how to perform this extraction in a laboratory setting.

Takeaways

• 🧪 The experiment demonstrates how to extract agar from red algae, specifically from the species Gelidium (referred to as 'glacial area').
• 🌊 Red algae used for agar extraction are commonly found in seawater environments.
• ⚖️ The process begins by weighing 1 gram of dried red algae material.
• ✂️ The algae (thallus) are cut into small fragments using a blade or scissors to increase surface area for processing.
• 🥼 The chopped algae are placed in a beaker and mixed with 20 ml of 5% NaOH (sodium hydroxide) solution.
• 🔥 The NaOH-treated algae mixture is incubated in a boiling water bath for about 1.5 hours to remove impurities.
• 🚿 After incubation, the material is washed 2–3 times with tap water using a muslin cloth to remove residual chemicals.
• ⚗️ The cleaned material is then treated with 20 ml of 1.5% H₂SO₄ (sulfuric acid) for 30 minutes at room temperature to further purify the sample.
• 💧 After acid treatment, the material is again washed thoroughly and boiled with 20 ml of distilled water on a hot plate until the volume reduces to one-third.
• 🧴 The boiled mixture is filtered through muslin cloth and the filtrate is poured into a petri dish for cooling and solidification.
• ❄️ Upon cooling, the extracted agar solidifies into a gel-like form, completing the extraction process.
• 🌱 The extracted agar serves as a key biological material, often used in laboratories for microbial culture and other scientific applications.

Q & A

What is the main topic of the video?

The main topic of the video is the extraction of agar from red algae, specifically from a type called *Gracilaria*, which is commonly found in seawater.

Why is it important to wear protective material before starting the extraction process?

Wearing protective material, such as gloves or lab coats, is important to ensure safety during the experiment, as the chemicals and materials involved may be hazardous.

What is the first step in the agar extraction process?

The first step is to weigh out 1 gram of the *Gracilaria* algae material that will be used for the agar extraction.

How should the *Gracilaria* algae be prepared for the extraction?

The algae should be cut into small fragments using a blade or scissors to facilitate the extraction process.

What is the purpose of using a 5% NaOH solution in the extraction process?

The 5% NaOH solution is used to help break down the algae and release the agar. It assists in dissolving some of the cellular structures in the algae, making the agar more accessible for extraction.

What happens after the NaOH solution is mixed with the algae?

After mixing the algae with the NaOH solution, the beaker is covered and incubated in a water bath at boiling temperature for 1 to 1.5 hours to allow the extraction to occur.

How many times should the material be washed after incubation in NaOH?

The material should be washed 2 to 3 times with tap water to remove any remaining NaOH and impurities.

What is the next chemical treatment after washing the material with water?

The material is then treated with a 1.5% sulfuric acid (H2SO4) solution for half an hour at room temperature to further purify the agar.

Why is distilled water used in the boiling step?

Distilled water is used to ensure that no additional impurities or contaminants are introduced during the boiling process. It helps to further dissolve the agar and concentrate it as the solution boils down.

How long should the solution be boiled on the hot plate, and why?

The solution should be boiled until the volume is reduced to one-fourth of the original. This step helps concentrate the agar and remove excess water, ensuring a higher yield of agar in the final product.

What happens after the boiling step is completed?

After boiling, the solution is transferred to a petri dish and left to cool. Once the solution solidifies, the agar can be collected, and the final product is a solidified form of agar, ready for use.

What are some applications of agar in biotechnology and other industries?

Agar is commonly used as a solidifying agent in microbiology for growing bacteria, in the food industry as a gelling agent, and in biotechnology as a medium for growing cultures or in the preparation of various gels and plates.