Tryptophan Broth is used to detect indole production by microorganisms that possess tryptophanase.

Tryptophan Broth | AS-1368 | Indole Test Medium for E. coli | AuSaMicS

$29.00 AUD

AuSaMicS Life Science • Indole Production Medium for Enteric Confirmation

Tryptophan Broth

Tryptophan Broth is used to detect indole production by microorganisms that possess tryptophanase. It is widely used in confirmatory workflows for Escherichia coli and related enteric bacteria in water, food, and microbiological identification systems.

Cat No.: AS-1368

Indole Test BrothTryptophan MediumAustralian Stock

Format: Dehydrated culture medium SKU: To be assigned Support: COA / technical support available

Application Summary

Professional laboratory use

Reliable workflow integration

Australian stock

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Overview & Applications

Primary Applications

Indole production test for bacterial differentiation
Confirmation of Escherichia coli in water and food workflows
Supportive test in enteric and Salmonella confirmation schemes
Routine teaching and QC laboratories

Key Features

Contains tryptophan substrate for indole detection
Simple broth system with clear confirmatory purpose
Compatible with Kovac's or related indole reagents
Useful in ISO-based confirmatory workflows

Typical Composition / Product Characteristics

Component / Attribute	Amount / Value	Function	Practical Role
Peptone / casein peptone	10.0 g/L	Nutrient base	Supports growth during indole test
Sodium chloride	5.0 g/L	Osmotic balance	Maintains suitable broth environment
DL / L-Tryptophan	1.0 g/L	Test substrate	Allows detection of tryptophanase activity
Final pH	7.2–7.5	Optimized test condition	Supports standard indole workflows
Use note	Kovac's reagent after incubation	Detection step	Red ring indicates positive indole production

Preparation, Incubation & Interpretation

Preparation

Dissolve 16 g in 1 L purified water, dispense into tubes, and autoclave at 121°C for 15 minutes.

Incubation / Use

Typical incubation is 18–24 hours at about 35–37°C; some ISO workflows specify defined conditions for specific applications.

Interpretation

After incubation, add Kovac's or equivalent indole reagent. A red ring in the upper reagent layer indicates indole-positive organisms; absence of the red reaction indicates a negative result.

Comparative Media / Workflow Position

Medium / Product	Primary Target	Principle	Typical Use	Key Advantage
Tryptophan Broth	Indole-positive bacteria	Tryptophanase detection	E. coli and enteric confirmation	Simple confirmatory broth
Tryptone Water	Indole-positive bacteria	Related indole test medium	General indole testing	Very widely used alternative
MRVP Broth	Enterics	Mixed acid / acetoin testing	IMViC workflow	Complements indole testing
Simmons Citrate Agar	Enterics	Citrate utilization	IMViC workflow	Complements indole testing

Recommended Workflow

1. Prepare broth tubes
Sterilize and dispense according to the SOP.

2. Inoculate test organism
Use a pure culture or validated confirmatory step.

3. Incubate
Follow the required time and temperature.

4. Add indole reagent
Read the top layer for a positive red indole reaction.

Strategic Use

Advantages

Simple and reliable indole test medium
Useful in E. coli and enteric confirmation workflows
Compatible with standard laboratory reagents and SOPs

Considerations

Requires addition of an indole detection reagent after incubation
Should be interpreted with the broader identification panel where relevant
Exact conditions may vary by standard method

Selection Guide

Use for indole production confirmation
Suitable for water, food, and enteric ID workflows
Good addition to IMViC-style and related biochemical schemes