Extra-Heavy Crude Oil Degradation by Alternaria sp. Isolated from Deep-Sea Sediments of the Gulf of Mexico

Abstract

The Gulf of Mexico (GoM) is an important source of oil for the United States and Mexico. There has been growing interest, particularly after the Deepwater Horizon oil spill, in characterizing the fungal diversity of the GoM and identifying isolates for use in the bioremediation of petroleum in the event of another spill. Most studies have focused on light crude oil bioremediation processes, while heavy crude oil (HCO) and extra-heavy crude oil (EHCO) have been largely ignored. In this work, we evaluated the ability of fungal isolates obtained from deep-sea sediments of the Mexican economic exclusive zone (EEZ) of the GoM to degrade HCO (16–20° API) and EHCO (7–10° API). Alternaria sp., Penicillium spp., and Stemphylium sp. grew with HCO as the sole carbon source. Remarkably, Alternaria sp. was the only isolate able to grow with EHCO as the sole carbon source, degrading up to 25.6% of the total EHCO and 91.3% of the aromatic fraction, as demonstrated by gas chromatography analysis of the saturate, aromatic, and polar fractions. These findings proved to be significant, identifying Alternaria sp. as one of the few fungi reported so far capable of degrading untreated EHCO and as a suitable candidate for bioremediation of EHCO in future studies.

Methane Generation from Anthracite by Fungi and Methanogen Mixed Flora Enriched from Produced Water Associated with the Qinshui Basin in China

“…Amorphotheca is known to utilize different kinds of organic substances such as alkanes, acetic acid, and lignocellulose biomass . It has been confirmed that Amorphotheca can degrade various inhibitor compounds such as a high level of acetic acid from pretreated lignocellulose feedstock, and it has been applied for producing ethanol, lactic acid, gluconic acid, and microbial lipid with a high product yield and zero wastewater generation. − Alternaria is one of only a few of fungi reported so far to be capable of degrading heavy crude oil, which is composed of PAHs and has a higher metabolization of the aromatic fraction , The growth of Aspergillus was also found on the surface of aromatic polyesters, demonstrating its remarkable ability to degrade complex aromatics, especially the high-molecular-weight PAHs .…”

Chemical Diversity and Antimicrobial Potential of Cultivable Fungi from Deep-Sea Sediments of the Gulf of Mexico

“…Twenty-nine fungal strains were isolated from deep-sea sediment samples collected from eight stations of the GoM during the Metagenomica-Malla Fina cruise (MET-I) and Metagenomics (MET-II) campaigns in 2016 and 2017, respectively, onboard the research vessel Justo Sierra of UNAM ( Table 1 ) [ 17 , 18 ]. Each axenic culture in the PDA plates was transferred to (1% of yeast extract, 2% of soy peptone, 2% of dextrose) medium and incubated for 5 d at RT in a shaker at 120 rpm.…”

“…Metagenomic analysis has shown that the GoM contains an unusual fungal diversity compared to marine sediments from other regions in the world. Interestingly, metabolically active fungi have not been studied as deeply as marine bacteria [ 8 , 9 , 17 , 18 ]. Recently, a series of cultivable fungi from sediments of two oil-drilling deep-sea oil reserves in the GoM were studied for their capacity to grow in media with hexadecane and 1-hexadecene as the only source of carbon [ 17 ].…”

Special Issue on Discovery and Research on Aquatic Microorganisms

“…The importance of filamentous fungi was assessed by Poli et al [2], Romero-Hernández et al [3], and by Dobretsov et al [4]. In the first case, the authors, by applying morphological, molecular and phylogenetic analyses, described the novel Corollospora mediterranea species complex (CMSC), isolated from different substrates in the Mediterranean Sea.…”

“…Following the Deepwater Horizon oil spill, interest in characterizing the fungal diversity in the Gulf of Mexico (GoM) rapidly increased. Romero-Hernández et al [3] focused on heavy crude oil (HCO) and extra-heavy crude oil, evaluating the ability of fungal strains isolated from deep-sea sediments of the GoM to degrade them. They demonstrated that species of Alternaria, Penicillium and Stemphylium, can use HCO as its sole carbon source, while a strain of Alternaria was the only one to grow in the presence of EHCO, displaying excellent degradative properties.…”