Spent Wash as an Alternative Medium for Growth of Rhizobium

The present study was aimed to use spent wash as a substitute for expensive commercial media for Rhizobial cultures. Growth of Rhizobium strains at different concentrations of spent wash was observed and found maximum at 50% spent wash. Bacteria were grown on 50% spent wash which produced remarkable results and competed with standard media like tryptone yeast extract, Rhizobium minimal and yeast extract mannitol media. Media was optimized using 50% spent wash along with two main ingredients used for Rhizobium namely yeast extract (1-7 g/L) and mannitol (1-7 g/L) in terms of OD at different intervals of time namely 24, 48 and 72 h. The maximum growth observed in 5 g/L in yeast extract and 2 g/L in mannitol at 24 h incubation period in all the strains. This study provides the information of nutritive, inexpensive and suitable medium for Rhizobial cultures.