Cellulosimicrobium funkei: A Novel Bacterium in Potassium Solubilization from Soil in Bangalore

Abstract— Potassium (K) is a very essential element needed by plants for healthy growth and good yield. Most soils have abundance of potassium underneath in rock as insoluble forms that are unavailable for plant use. This research was carried out to join in the search to unearth microorganisms from the rhizosphere soil that are able to act on the mineral containing substances, solubilizing them to release the needed soluble form of the potassium for plant use. An isolate, which was characterized and identified to be Cellulosimicrobium funkei, showed significant solubilization on feldspar (a potassium containing compound) supplemented media. It is novel for potassium solubilization. The amount of potassium released by the isolate in comparison to reference cultures varied but favourably compared with the reference cultures. In glucose amended broth, solubilization was: Cellulosimicrobium funkei 7.04mg/l, Enterobacter hormaechei 7.15 mg/l and 6.91mg/l for Aspergillus terreus. Urea supplemented broth: Cellulosimicrobium funkei 5.45mg/l, Enterobacter hormaechei 5.38mg/l and Aspergillus terreus 6.33mg/l. KCl supplemented broth: Cellulosimicrobium funkei 10.23mg/l, Enterobacter hormaechei 8.05mg/l and Aspergillus terreus 9.11mg/l. For temperature, the cultures solubilized best at these respective temperatures: Cellulosimicrobium funkei 27oC, Enterobacter hormaechei 35oC and Aspergillus terreus 30oC. PH was 7.5 for Cellulosimicrobium funkei, 8 for Enterobacter hormaechei and for 7.5 for Aspergillus terreus. When they were now cultured using the combination of the above parameters Cellulosimicrobium funkei, Enterobacter hormaechei and Aspergillus terreus gave a maximum yield of 7.24mg/l, 7.03mg/l and 6.81mg/l of solubilized potassium respectively. This means that the isolate Cellulosimicrobium funkei yielded more solubilized potassium from feldspar than the reference cultures and could therefore be a better potassium solubilizer