Anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) by fungi isolated from anaerobic coal-associated sediments at 2.5 km below the seafloor
Anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) by fungi isolated from anaerobic coal-associated sediments at 2.5 km below the seafloor
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从海底以下 2.5 公里厌氧煤伴生沉积物中分离出的真菌对多环芳烃 (PAH) 的厌氧生物降解
DOI：
10.1016/j.chemosphere.2022.135062
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发表时间：
2022-05-28
期刊：
影响因子：
8.8
通讯作者：
Liu, Chang-Hong
中科院分区：
文献类型：
--
作者：
ul Arifeen, Muhammad Zain;Ma, Yunan;Liu, Chang-Hong
真菌是深层生物圈中的主要真核生物，在海底以下-2.5公里的厌氧含煤沉积物中大量存在。但真菌是否能够降解并利用煤炭在厌氧的海底环境中持续生长仍是个未知数。根据生物降解研究，我们发现从-1.3-2.5kMBsf深度的海底沉积物中分离出的真菌对多环芳烃(PAHs)的厌氧降解率很大(3-25%)。其中，白腐菌裂殖酵母20R-7-F01对菲(Phe)、芘(Pyr)和苯并[a]芘(BaP)的降解率最高，分别为25%、18%和13%。厌氧培养20d后，Phe得到了较好的利用，降解率约为40.4%。此外，真菌降解多环芳烃的能力与真菌的厌氧生长呈正相关，表明真菌可以在缺氧条件下以多环芳烃为唯一碳源。此外，真菌对多环芳烃的降解与羧基酶的活性有关，而与漆酶(Lac)、锰过氧化物酶(MnP)和木质素过氧化物酶(LIP)等木质素修饰酶的活性关系不大或几乎没有关系。这些结果表明，在厌氧条件下，海底真菌具有降解和利用多环芳烃作为碳源和能源的特殊机制。此外，生活在海底以下沉积物中的真菌不仅可能在深部生物圈厌氧环境中的碳循环中发挥重要作用，而且通过利用多环芳烃或相关化合物作为碳源和能源，能够在海底深层沉积物中持续存在数百万年。这种厌氧生物降解能力使这些真菌适合于生物修复来自缺氧环境的有毒污染物，如多环芳烃。
Fungi represent the dominant eukaryotic group in the deep biosphere and well-populated in the anaerobic coal bearing sediments up to-2.5 km below seafloor (kmbsf). But whether fungi are able to degrade and utilize coal to sustain growth in the anaerobic sub-seafloor environment remains unknown. Based on biodegradation investigation, we found that fungi isolated from sub-seafloor sediments at depths of-1.3--2.5 kmbsf showed a broad range of polycyclic aromatic hydrocarbons (PAHs) anaerobic degradation rates (3-25%). Among them, the white-rot fungus Schizophyllium commune 20R-7-F01 exhibited the highest degradation, 25%, 18% and 13%, of phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP); respectively, after 10 days of anaerobic incubation. Phe was utilized well and about 40.4% was degraded by the fungus, after 20 days of anaerobic incubation. Moreover, the ability of fungi to degrade PAHs was positively correlated with the anaerobic growth of fungi, indicating that fungi can use PAHs as a sole carbon source under anoxic conditions. In addition, fungal degradation of PAHs was found to be related to the activity of carboxylases, but little or nothing to do with the activity of lignin modifying enzymes such as laccase (Lac), manganese peroxidase (MnP) and lignin peroxidase (LiP). These results suggest that sub-seafloor fungi possess a special mechanism to degrade and utilize PAHs as a carbon and energy source under anaerobic conditions. Furthermore, fungi living in sub-seafloor sediments may not only play an important role in carbon cycle in the anaerobic environments of the deep biosphere, but also be able to persist in deep sediment below seafloor for millions of years by using PAHs or related compounds as carbon and energy source. This anaerobic biodegradation ability could make these fungi suitable candidates for bioremediation of toxic pollutants such as PAHs from anoxic environments.