Abstract:
Burkholderia anthina R-4183, Burkholderia diffusa R-15930 and Burkholderia stabilis LMG 14294 isolated
from green house soils (Gongju-Gun area, South Korea) were characterized and their phosphate solubilizing
ability was assessed. Under in vitro culture conditions, all three species were proved to be effective in
solubilizing phosphates in varying degrees. Strain Burkholderia anthina exhibited the highest phosphate
solubilization in NBRIP medium (665 µg ml-1) followed by Burkholderia diffusa (630 µg ml-1) and
Burkholderia stabilis (578 µg ml-1). However, solubilization of FePO4 and AlPO4 was found to be poor in all
the strains. Acidification by means of gluconic and oxalic acids accumulation in the culture medium could be
the possible mechanism responsible for phosphate solubilization. Glucose at the rate of 3% was found be the
best carbon source for Burkholderia anthina while other two Burkholderia species showed maximum
phosphate solubilization at 2% of glucose. In the case of nitrogen sources, ammonium and nitrate were equally
effective in solubilizing phosphates by Burkholderia species. Despite a slight decrease in phosphate
solubilization observed at increasing temperature, all three Burkholderia species could withstand a
temperature of 30-35℃, pH at the range of 7-9 and the presence of NaCl (up to 2.5%) without much
compromising the phosphate solubilization. As shown with potted mung bean seedlings, all the three isolates
could enhance soil fertility and plant growth indicating their great potential to be used as bio-inoculants.
