Bioremediation of Cutting Pits by Autochtonous Bacteria-Fungi Consortia

The aim of this work is to verify the potential of a consortium of autochthonous bacteria and fungi, isolated from samples of contaminated soils and water collected in a site containing cutting pits muds, in order to evaluate enhancing in biodegradation of hydrocarbons content. This innovative technique would take advantage of the synergistic effect of bacteria and fungi. In addition, this technique would allow to avoid the introduction of commercial allochthonous microflora for soil remediation and the use of chemical products for tool cleaning. Samples retrieved from a production site were used to isolate bacterial and unicellular fungal species able to grow on hydrocarbons were demonstrated to be able to degrade light and "diesel-like" hydrocarbons under laboratory conditions and in liquid cultures in less than a month. The activity of the consortium was also tested on crude oil, showing an overall degradation of the analyzable fraction greater of sixty percent after a 14-day incubation. Low C number linear hydrocarbons were the preferred substrate, but also cycloalkanes and mono- and di-aromatics seemed to be a good growth substrate. Probably, the action of enzymes secreted by fungal strains could enhance the degradation of complex molecules such as polycyclic aromatic hydrocarbons. Lab tests of consortium efficiency on mud samples are ongoing and an on-site pilot test is foreseen, to prove the activity of the consortium under the challenging field conditions. The development of fungal and bacterial consortia for degradation of complex hydrocarbon mixtures will represent an innovative approach that combines the action of enzymes secreted by fungi followed by the bacterial breakdown, a synergistic effect which could potentially increase the rate and effectiveness of hydrocarbons decontamination.