Evaluation of biodiesel production for some <i>Penicillium</i> sp. isolates from Aramco oil field, Saudi Arabia, Western region

In this investigation, we isolated fifteen fungal isolates from three sites belonging to the Saudi Aramco Oil Company. The first site showed the highest number of isolates (9), compared with four and two isolates for the third and second sites, respectively. Three isolates (A4, A8, and B5) reflected a distinguishably superior biodiesel yield compared with other fungal isolates. Based on the 18S ribosomal RNA gene sequence, three isolates were identified as Penicillium commune (for A4 and A8 isolates) and Penicillium expansum (for isolate B5) and submitted to the gene bank with PP330078, PP330079, and PP330080 accession numbers, with 100% identity. Gas chromatography was used to compare the biodiesel profiles of the three isolates and showed that An A4 isolate is considered the best biodiesel production isolate as it contains an elevated percentage of mono- and polyunsaturated fats, primarily 15.4% O.C., 34.8% L.I., 1.1% α-linoleic acid, and 20.3% arachidonic acid, and a small proportion of saturated fats, mainly 22.7% palmitic acid and 3.4% stearic acid.