To produce good quality nitrogen inoculants, it is desired to obtain effective rhizobia with good nodulation and nitrogen fixing capacity to the host plant. It is therefore, required to find a nutrient medium for their growth and optimize the pH, temperature, incubation period and aeration. This study was conducted to evaluate the use of sugar waste (molasses) as an alternative growth medium for the cultivation of Rhizobium and to determine the optimum environmental parameters such as pH and temperature. Growth and population count of Rhizobium trifolii (MTCC 905) at different concentrations of sugar waste was monitored by recording Optical Density (OD) and Colony forming unit (cfu mL-1). Growth and population count were highest at 10% concentration i.e., 0.706±0.012 and 8.98±0.12, respectively. After optimizing the concentration of sugar waste growth pattern of R. trifolii was observed at 10% sugar waste concentration along with different synthetic media by recording Optical Density (OD) at 600 nm after 12 to 60 h. Cells of fast growing rhizobia grow rapidly on medium containing only 10% sugar waste and growth was superior to that of the control (standard media) used for Rhizobium. A pH of 7.0, temperature of 28°C and 48 h incubation period were most appropriate for Rhizobium trifolii (MTCC 905). The present study concludes that 10% sugar waste is complete medium for the rhizobial inoculants.
Ashok Kumar Singh, Gauri , Rajendra Prasad Bhatt and Shailja Pant, 2011. Optimization and Comparative Study of the Sugar Waste for the Growth of Rhizobium Cells Along with Traditional Laboratory Media. Research Journal of Microbiology, 6: 715-723.