Study of Lipase Production and Lipids Accumulation of Oleaginous Fungi Isolated from Oil-rich Soil in Basrah

Abstract

Objectives: The present study was aimed for rapid identification of lipids accumulation of oleaginous fungi isolated from oil-rich soil in Basrah /Iraq. Methods: Soil samples were collected from oil-rich soil of Basrah-Iraq; dilution plate method was used to identification of fungi, as well as the percentage of frequency and occurrence was determined after identification of fungal isolates according of morphological features. Congo red agar was employed for evaluation of lipase production of fungal isolates, while lipid accumulation of fungal isolates was estimated by using Sudan black B technique. As well as, four fungal isolates that revealed highest lipid accumulation were underwent of DNA extraction and the result of genomic DNA was amplified with two universal primers ITS1 and ITS4, PCR products were purified and sequenced, furthermore, sequencing results of fungal species were identified in “ BLAST ” provided by the NCBI. Results: The study was showed that isolation of 8 filamentous species due to Deuteromycetes. Aspergillus flavus was revealed high percentage of frequency with 18.18%, while the high percentage of occurrence for Scytalidium japonicum by 27.5%. Lipolytic activity test was showed that the majority of fungal isolates have the ability of lipase production 90%, however, the highest precipitation zone was due to A.flavus 55mm, followed with A.niger 47mm. As well as all selected isolates were given positive results when staining with Sudan Black B stain that used for intracellular lipids detection. Furthermore, the result of molecular identification showed that recorded Aspergillus flavus KAIN2 as new strain in Gene Bank that gets accession number MN508371. Conclusion: Aspergillus flavus and Scytalidium japonicum were showed high percentage of frequency and occurrence. The majority of fungal isolates were appeared lipase activity, while all of them were showed ability of lipid accumulation when staining by Sudan black B.