Tracking of phenol bioremediation by two marine eco-friendly Aspergillus terreus MHG30 (ON649683) and A. terreus MHG60 (ON649704) strains at optimum conditions

The rapid population and industrial development worldwide have increased chemical pollutants reaching the marine environment. In the present study, marine fungi were isolated from two collected petroleum sites at the Gulf of Suez, Red Sea, Egypt, during spring (2021). Fungal isolates were purified and screened for their ability to bio-remediate phenol and ortho-cresol bioremediation. Out of twenty two, eight marine fungal isolates represented their potency for the bioremediation of these phenolic compounds. These selected fungi were identified morphologically and numbered according to the AUMC center as Aspergillus flavus 15524, Aspergillus terreus 15525, Aspergillus flavus 15526 and Aspergillus terreus 15527 for phenol bioremediation, and Fusarium oxysporum 15528, Fusarium oxysporum 15529, Aspergillus terreus 15530 and Aspergillus terreus 15531 for o-cresol bioremediation. The two most potent marine fungal isolates able to degrade phenols with high efficiency are strains number 15527 and 1553 which were identified by DNA sequence as A. terreus MHG30 (ON649683) and MHG60 (ON649704), respectively. The optimum condition for phenol degradation by A. terreus MHG30 were 1000 mg/l phenol, pH=8 at 34 ͦC, and contact time 168 hrs., while A. terreus MHG60 showed optimum condition using 250 mg/l o-cresol, pH 6 at 31 C⁰ after 168 hrs. Maximum degradation rates were recorded at 88.34 and 98.1 % for ON649683 and ON649704 strains, respectively. Both strains, ON649683 and ON649704 were acquired with 61 and 64 inhibitory % for oxidase with 81 and 78 % for peroxidase enzymes, respectively. The K_m/V_max of both isolates was achieved at 0.18, 0.19, 0.03, and 0.29 for the studied enzymes. In addition, the active compounds of GC-Mass (Hexadecanoic acid, methyl ester, and 6, 9, 12-octadecatrienoic acid) are used to determine the unique eco-friendly compounds that result from the bioremediation procedure for phenol and o-cresol.