Characterization of Hydrocarbon Utilizing Bacteria and Fungi Associated with Crude Oil Contaminated Soil

Abstract

<jats:p>Many substances known to have toxic properties are regularly introduced into the environment through human activity. These substances which include hydrocarbons range in degree of toxicity and danger to human health. Frequent oil spills incidents have become a problem to ecological protection efforts. Conventional methods to remove, reduce or mitigate toxic substances introduced into soil via anthropogenic activities suffer setbacks due to the level of risk involved but bioremediation offers an alternative method to detoxify contaminants especially if the soil conditions are amended with organic nutrients or growth enhancing co-substrates. This study was therefore aimed characterizing hydrocarbon utilizing microorganisms associated with crude oil contaminated soils. Soils were obtained from the Rivers State University Agricultural farm contaminated deliberately with crude oil and allowed for 21 days to mimic the natural polluted soil. Sample collection and analyses were carried out according to standard microbiological procedures while characterization of the isolates was done using genomic studies. The results of microbial counts obtained from the soil samples for total heterotrophic bacteria ranged from 2.10 x108 to 2.58 x108 cfu/g, Total heterotrophic fungi had 1.6 x105 to 2.0 x105 cfu/g while the hydrocarbon utilizing bacteria ranged from 8.0 x103 to 5.0 x104 cfu/g and total hydrocarbon utilizing fungi ranged from 9.0 x103 to 7.0 x104 cfu/g in the contaminated soil. Five hydrocarbon utilizing bacterial species were identified as Staphylococcus saprophyticus, Bacillus amyloliquefaciens, Pseudomonas aeruginosa, Comamonas testosteroni and Chryseobacterium cucumeris while five hydrocarbon utilizing fungal species were identified as Penicillium citrinum, Penicillium brocae, Fusarium solani, Kodamaea ohmeri and Lentinus squarrosulus. Bacillus and Penicillium species were predominantly isolated from the soil. This may be due to the ability of the organisms to produce spores, which may shield them from the toxic effects of the hydrocarbons. Since these organisms are able to utilize crude oil as their sole carbon source. Hence, can be used for bioremediation of crude oil polluted environment.</jats:p>

Soil Microbiome Structure and Function in Ecopiles Used to Remediate Petroleum-Contaminated Soil

“…The dominant fungal genera found in the Ecopile soil were Ochroconis (∼15%), Pseudallescheria (9%), Gaertneriomyces (9%), and Fusarium (7%), many of which have been reported to be present in contaminated soils. Borowik et al, (2017) showed that hydrocarbon-polluted soil was dominated by fungi from the genera Fusarium (37.9%), Candida (13.8%), Microsporum (13.8%), and Penicillium (13.8%), while Ogbonna et al, (2020) identified a number of hydrocarbon-degrading fungi in oil-contaminated soil including some species of Fusarium, Penicillium, Kodamaea, and Lentinus. Wu et al, (2020a) and Wu et al, (2020b) reported the presence of Ochroconis species in two different petroleumcontaminated soils in China at relative abundances of 1-5%.…”

Mycoremediation of polyaromatic hydrocarbon contaminated anoxic ecosystem by <i>Trichoderma</i> species in synergy with <i>Bacillus</i> species

“…Evaluation of the microscopic/macroscopic characteristics revealed the presence of Aspergillus niger, Mucorsp, Aspergillus flavus, Fusarium sp, Aspergillus japonicas, Rhizopus nigricans, Trichoderma sp, Penicillum sp. The frequency of occurrence of fungal isolates showed that a total of twentythree (23) fungal isolates were gotten from the samplesthe frequency of occurrence of the isolatesis higher than four (4) isolates reported by Ogbonna et al, (2020).The possible reason could be as a result of the duration of simulation, in this case 21 days simulation was allowed in order to mimic a naturally polluted soil ( (Varjani and Gnansounou, 2017) Aspergillus sp and Fusarium sp were the most frequent occurring isolates identified during the course of this study. This is followed by Penicillium sp, Mucor sp with Rhizopus sp and Trichoderma sp being the least as shown Table 3.…”

“…SD-43 from steel industry waste posing inbuilt mechanisms for adapting to their environment. It was noted that this organism plays a vital role in remediation and clean-up of oil spillage by utilizing crude oil as its sole carbon source, low cost and environmentally friendly (Guerra et al, 2018) and spore former shielding them from the noxious effects of the hydrocarbon (Ogbonna et al, 2020).…”

“…0.1ml aliquot of the dilutions starting from 10 -3 and 10 -4 were noculated into Petri dishes containing potato dextrose agar (PDA) in triplicate and spread with sterile bent glass rod. The plates were incubated at 27 o C for 3-7 days (Ogbonna et al, 2020).…”

“…Aliquot of 0.1ml of the appropriate dilution 10 -3 and 10 -4 was inoculated in triplicates by spread plate method respectively.A sterile filter paper saturated with crude oil was place inside the cover (lid) of the Petri dish with the aid of a sterile forcep immediately, the plates were closed, inverted and incubated at 28 o C for 3-8 days. The filter paper saturated with crude oil seated as a solesource of carbon and energy (Ogbonna et al, 2020).…”