Studies on the morphology, phylogeny, and bioremediation potential of Penicillium citrinum and Paecilomyces variotii (Eurotiales) from oil-contaminated areas.

Abstract

Crude oil pollution is one of the most arduous issues to address, as it is hazardous to both public health and the environment. The discovery of novel biosurfactants-producing fungi and bacteria is in high demand due to their excellent properties and wide range of applications. The aim of this research is to isolate a powerful biosurfactant-producing fungus from the crude oil site near Barauni oil refinery in Bihar, India. Standard protocols were used to collect samples from the site. An integrative taxonomic approach was used, which included morphological, molecular, and phylogenetic analysis. The use of plating samples on Bushnell-Hass (BH) media aided in the isolation of a fungal strain from an enrichment culture. Two fungal strains isolated from contaminated soils, Penicillium citrinum and Paecilomyces variotti, showed potent oil degrading activity in a single culture. For preliminary biosurfactants screening, drop collapse assays, oil spreading, and emulsification activity tests were used. The results showed that the cultures performed well in the screening test and were further evaluated for degradation capacity. Different treatment periods (0, 3, 6, 9, 12, and 15days) were used to observe degradation in single cultures. A steady drop in pH, an alteration in optical density and an increase in carbon dioxide release showed the ability of fungal strain to degrade the crude oil in a single culture. Fungi mycelia provide a larger surface area for absorption and degradation of the pollutants in contaminated environment. They produce extracellular enzymes to degrade the oil, and at the same time absorb and utilise carbon, allowing them to remove toxic substances from the oil. Thus, they could be candidates for bioremediation of a hydrocarbon-contaminated site.