This document discusses various microbiological techniques for isolating and culturing microorganisms, including serial dilution, pour and spread plating, using a micromanipulator to isolate single cells under a microscope, and the roll tube method for culturing obligate anaerobes by pumping inert gas through molten agar in a test tube to remove oxygen before solidification.

1. Types of streak plate method
Serial dilution
Fig: Types of streak plate techniques
Fig: Serial dilution method

2. Fig: Pour plate and spread plate technique

3. Micromanipulator
 Using micromanipulator one can able to pick a single cell from a mixed culture
 This instrument is used in conjugation with the microscope to pick a single cell from a hanging drop
preparation.
Fig: Micromanipulator Fig: Diagrammatical representation for isolation of single cell

4. Roll tube method
Using this method, obligate anaerobes can be isolated
Inert gas or CO2 is pumped through the test tube to remove oxygen
Using nutrient agar, melt two ml at 50 degree c, add one ml to a test tube and stir
To set the agar film on the slides of testube, inoculum is added and the tubes are rolled under
flowing water
Fig: Roll tube method

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