Glutamate Starch Phenol Red Agar Base (GSP Agar Base) – Selective Medium for Pseudomonas and Aeromonas (250g)

Glutamate Starch Phenol Red Agar Base (GSP Agar Base), also known as Pseudomonas Aeromonas Selective Agar (acc. to Kielwein), is a selective and differential culture medium used for the isolation and identification of Pseudomonas and Aeromonas species from clinical, food, and environmental samples.

The medium contains glutamate and starch as carbon sources and phenol red as a pH indicator, allowing differentiation based on carbohydrate utilization.
For selectivity, the medium requires supplementation with:

• Penicillin solution

• Pimaricin solution

This formulation is widely applied in food microbiology, water quality testing, and clinical diagnostics for detecting Pseudomonas and Aeromonas species.

Preparation & Instructions:

1. Suspend 44.86 g of the medium in 1 L distilled or deionized water.

2. Heat while stirring, bring to boil, and continue boiling for at least 1 minute until dissolved.

3. Dispense into appropriate containers.

4. Sterilize by autoclaving at 121°C for 15 minutes. Shake well after sterilization to avoid sedimentation.

5. Cool to 45–50°C.

6. Under aseptic conditions, supplement every 100 ml of medium with:

   • 1 vial Penicillin solution

   • 1 vial Pimaricin solution

7. Mix gently, pour into sterile Petri dishes, allow to solidify, and use as required.