Polycyclic aromatic hydrocarbons (PAHs) are a large group of chemicals. They represent an important concern due to their widespread distribution in the environment, their resistance to biodegradation, their potential to bioaccumulate and their harmful effects. Several pilot treatments have been implemented to prevent economic consequences and deterioration of soil and water quality. As a promising option, fungal enzymes are regarded as a powerful choice for degradation of PAHs. Phanerochaete chrysosporium, Pleurotus ostreatus and Bjerkandera adusta are most commonly used for the degradation of such compounds due to their production of ligninolytic enzymes such as lignin peroxidase, manganese peroxidase and laccase. The rate of biodegradation depends on many culture conditions, such as temperature, oxygen, accessibility of nutrients and agitated or shallow culture. Moreover, the addition of biosurfactants can strongly modify the enzyme activity. The removal of PAHs is dependent on the ionization potential. The study of the kinetics is not completely comprehended, and it becomes more challenging when fungi are applied for bioremediation. Degradation studies in soil are much more complicated than liquid cultures because of the heterogeneity of soil, thus, many factors should be considered when studying soil bioremediation, such as desorption and bioavailability of PAHs. Different degradation pathways can be suggested. The peroxidases are heme-containing enzymes having common catalytic cycles. One molecule of hydrogen peroxide oxidizes the resting enzyme withdrawing two electrons. Subsequently, the peroxidase is reduced back in two steps of one electron oxidation. Laccases are copper-containing oxidases. They reduce molecular oxygen to water and oxidize phenolic compounds.

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Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by fungal enzymes: A review.

Principles of microbial degradation of petroleum hydrocarbons in the environment

Nitrification and denitrification processes for mitigation of nitrous oxide from waste water treatment plants for biovalorization: Challenges and opportunities

Due to progress in science and technology, several harmful polycyclic aromatic hydrocarbons are synthesized and released into the environment. In the present investigation, a phenanthrene- and pyrene-degrading white rot fungi Ganoderma lucidum strain CCG1 was isolated from the Janjgir Champa district of Chhattisgarh, India, and then the degradation of phenanthrene and pyrene was estimated by high-performance liquid chromatography. It was found that G. lucidum able to degrade 99.65% of 20 mg/L of phenanthrene and 99.58% of pyrene in mineral salt broth after 30th day of incubation at 27 °C. G. lucidum produced significant amounts (p < 0.0001) of ligninolytic enzymes (Laccase, lignin peroxidase and manganese peroxidase) in the phenanthrene- and pyrene-containing mineral salt broth. G. lucidum produced maximum 10,788.00 U/L laccase, 3283.00 U/L Lignin peroxidase and 47,444.00 U/L Manganese peroxidase enzymes in the presence of phenanthrene and produced maximum 10,166.00 U/L laccase, 3613.00 U/L lignin peroxidase and 50,977.00 U/L manganese peroxidase enzymes in the presence of pyrene. Therefore, G. lucidum will be a potent phenanthrene and pyrene degrader from the environment.

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Degradation of polycyclic aromatic hydrocarbons (phenanthrene and pyrene) by the ligninolytic fungi Ganoderma lucidum isolated from the hardwood stump

Bioremediation of triphenyl phosphate by Brevibacillus brevis: Degradation characteristics and role of cytochrome P450 monooxygenase.

Contrasting characteristics of anthracene and pyrene degradation by wood rot fungus Pycnoporus sanguineus H1

Heterotrophic nitrifying bacteria are attracting increasing interest due to their advantages in treatment of wastewater with high nitrogen concentration. In this work, four bacterial isolates (WS-1, WS-4, WS-6, and WS-7) with the capability of simultaneous heterotrophic nitrification and aerobic denitrification from soil, sludge, and water by a fast isolation procedure were studied. Isolates WS-1, WS-6, and WS-7 were identified as Pseudomonas sp. and WS-4 as Agrobacterium sp. based on 16S rRNA gene sequence analysis. All four isolates could utilize ammonia, nitrate, and nitrite as sole nitrogen source and the metabolic characteristics were shown to be related with the genus. In addition, Agrobacterium sp. WS-4 accumulated less nitrate than the three Pseudomonas sp. strains with ammonia as the sole nitrogen source. When nitrate or nitrite was the sole nitrogen source, Agrobacterium sp. did not produce ammonia, and it consumed the least nitrogen compared with the three Pseudomonas sp. isolates. Our studies implied that Pseudomonas sp. strains had great potential in treating high nitrogen in wastewater.

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Xuanzhen Li

Papers

Contrasting characteristics of anthracene and pyrene degradation by wood rot fungus Pycnoporus sanguineus H1

Heterotrophic nitrification and aerobic denitrification by four novel isolated bacteria