Isolation and Diagnosis of Fungal Isolates Producing
Antimicrobial Agents from Petroleum Soil
ABSTRACT
Objective: The present study aims to isolate and diagnose of fungi from soil polluted with oils and
investigate their antimicrobial ability.
Methods: Soil samples were collected from different areas of oil-polluted soils in Karbala city, Iraq for the
period from September to December 2019, cultured on the potato dextrose agar(PDA). A week later, the
purification processes were carried out to obtain pure colonies of isolated fungi. The isolated fungi were
diagnosed.The fungal isolates were then inoculated in the nutrient broth. After 10 days of incubation, the
filtration and centrifuge processes were measured for production media. Then the antimicrobial activity were
measured by microtiter plate method.
Results:Twenty-four fungal isolates were obtained in this study and are belong to five fungal species,
including: Aspergillus niger ( 9 isolates ) , Aspergillus flavus ( 4 isolates ), Aspergillus fumigatus ( 1 isolate ) ,
Rhizopus stolonifera ( 4 isolates ) and Phoma medicaginis Malbra var. pinodella ( 6 isolates ).
Six filtrate fungal isolates out of 24 fungal isolates display an antimicrobial activity versus E. coli, five filtrate
fungal isolates display an antimicrobial activity versus Staphylococcus aureus, three filtrate fungal isolates display
an antimicrobial activity versus Klebsiella sp and three filtrate fungal isolates showed an antimicrobial activity
against Candida albicans.
Conclusions:The fungal species found in the soil polluted with oils in the city of Karbala are five fungal
species. Some of these isolates have antimicrobial activity versus gram positive and negative bacteria in
addition to Candida albicans.
Keywords: Fungi, Soil, Oil, Antimicrobial activity
