In this paper, the production of phosphate biofertilizers from bones by phosphate-solubilizing bacteria Bacillus megaterium is presented. The biofertilizers used in this study contain phosphorus compounds that are in available form to plants as well as components of growth medium. The solubilization was performed under two conditions; with chlorides and with sulphates instead of chlorides. Three biofertilizer forms are proposed in relation to the doses of bones applied in the solubilization process (4, 10 or 20 g L-1). The solubilization degree varied according to the bacterial medium formulation and the bones doses. The replacement of chlorides with sulphates yielded a lower growth rate, and resulted, in a lower solubilization. The specific growth rate of the cells of B. megaterium in a sulphate medium was lower than compared with the specific growth rate of cell culture in a medium of chlorides of about 22.4, 39 and 14%, for 4, 10 and 20 g L-1 of bones concentration, respectively. In the stationary phase, the solubilization factor (SF) was higher (61.7%) for the solubilization process conducted in a medium with chlorides − Cbone 4 g L-1, compared with the solubilization process conducted in the medium of sulphates (52.7%).
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