The impact of Bacillus megaterium on the solubilisation of phosphorus from sewage sludge

Abstract

The aim of this work was to analyse the influence of Bacillus megaterium bacteria on the solubilisation of phosphorus in a sewage sludge. The tests were carried out for two different temperature conditions, i.e. 21 and 36ºC. In the experiment, lasting 23 days, the course of phosphorus solubilization under the influence of a changing population of bacteria was determined using Golterman’s speciation analysis. This method allows to estimating the fraction of bioavailable phosphorus in the tested samples. The obtained results allow one to state that the population size of Bacillus megaterium bacteria changes, while the intensity of these changes depends on temperature and organic acids produced in metabolic processes change the pH of the environment, which affects phosphorus solubilisation and its speciation. The increase in the population of bacteria is accompanied by the increase in bioavailable phosphorous forms, and thus the release of phosphorus contained in the form of sparingly soluble forms in soil. The above fact is extremely important when considering the use of sewage sludge for natural purposes.