Novel application of κ-carrageenan: As a gelling agent in microbiological media to study biodiversity of extreme alkaliphiles

In the present investigation a novel application of κ-carrageenan, as a gelling agent for isolation, purification and identification of extreme alkaliphilic bacteria has been explored. The potassium salt of κ-carrageenan was an appropriate substitute of agar for preparation of solid medium, particularly for isolation of extreme alkaliphiles, as agar de-polymerizes at pH > 12.5. The purpose of formulating a new, stable, highly alkaline, solid medium was to study the diversity of extreme alkaliphilic bacteria by means of conventional cultivation techniques allied with molecular tools. The medium having pH in the range of 8.0–13.5 was used to isolate extreme alkaliphiles in pure form.