Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University (ACU), 4th Industrial Area, 6th of October City, Cairo, 12566, Egypt.
Department of Microbiology and Immunology, Faculty of Pharmacy, Modern Sciences and Arts University (MSA), 6th of October City, Cairo, Egypt.
Int Microbiol. 2019 Jun;22(2):217-225. doi: 10.1007/s10123-018-00041-5. Epub 2018 Nov 15.
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) using Pleurotus ostreatus was investigated in the current study along with the expression levels of laccase genes involved in biodegradation under variable conditions. Biodegradation of PAHs (naphthalene, anthracene, and 1,10-phenanthroline) was detected spectrophotometrically. Recorded data revealed that biodegradation of the tested PAHs was time dependent. Elevated level of naphthalene biodegradation (86.47%) was observed compared to anthracene (27.87%) and 1,10-phenanthroline (24.51%) within 3 days post incubation. Naphthalene was completely degraded within 5 days. Further incubation enhanced the biodegradation of both anthracene and 1,10-phenanthroline until reaches 93.69% and 92.00% biodegradation of the initial concentration within an incubation period of 11 and 14 days, respectively. Naphthalene was selected as a PAH model. HPLC and thin layer chromatography of naphthalene biodegradation products at time intervals proposed that naphthalene was first degraded to α- and β-naphthol which was further metabolized to salicylic and benzoic acid. The metabolic pathway of naphthalene degradation by this fungus was elucidated based on the detected metabolites. The expression profile of six laccase isomers was evaluated using real-time PCR. The transcriptome of the fungal laccase isomers recorded higher levels of transcription under optimized fermentation conditions especially in presence of both naphthalene and Tween 80. The accumulation of such useful metabolites from the biodegradation of PAH pollutants recommended white rot fungus as a potential candidate for production of platform chemicals from PAH wastes.
本研究考察了糙皮侧耳（Pleurotus ostreatus）对多环芳烃（PAHs）的生物降解作用，并在不同条件下，研究了参与生物降解的漆酶基因的表达水平。采用分光光度法检测 PAHs（萘、蒽和 1,10-菲咯啉）的生物降解情况。记录的数据显示，所测试的 PAHs 的生物降解随时间而变化。与蒽（27.87%）和 1,10-菲咯啉（24.51%）相比，萘的生物降解水平（86.47%）在孵育 3 天后显著升高。萘在 5 天内完全降解。进一步的孵育提高了蒽和 1,10-菲咯啉的生物降解率，分别在 11 和 14 天的孵育期内达到 93.69%和 92.00%的初始浓度降解率。选择萘作为 PAH 模型。在不同时间间隔对萘生物降解产物进行 HPLC 和薄层层析，提出萘首先降解为α-和β-萘酚，然后进一步代谢为水杨酸和苯甲酸。根据检测到的代谢物阐明了该真菌降解萘的代谢途径。采用实时 PCR 评估了 6 种漆酶同工酶的表达谱。真菌漆酶同工酶的转录组在优化的发酵条件下记录到更高的转录水平，特别是在萘和吐温 80 存在的情况下。从 PAH 污染物的生物降解中积累这些有用的代谢物，建议白腐真菌作为从 PAH 废物生产平台化学品的潜在候选物。
