A Study On Biodegradation Of Nonylphenol By Estuarine Sediment-Derived Fungi From Jiaozhou Bay

Nonylphenol was a kind of endocrine disruptors that can cause cancer, deformity and mutagenicity. NP was easily accumulated in organism and could be transmitted through the food chain to human. The NP pollution in water and sediment was becoming increasingly serious, and had heavily threat to the healthy development of the ecological environment. Because of low water solubility, NP was easily to adsorpt on particles and accumulate in sediments. It aggravated the influence to the benthos.The transformation of NP in sediment directly affected their environmental fate, biological utilizability and ecological toxicity. To now, biodegradation was the main transformation/removal way of NP in the sedimentary environment. But the domestic NP biodegradation research was limitted, and the research emphasis was basically focus on the NP governance. There was rare research on the simulation of environmental conditions to NP environmental behavior study. The domestic NP biodegradation research was mostly focused on bacteria, and only a few results related to fungal.In our research, several fungi were isolated from the estuarine sediments of Jiaozhou bay, where were contaminated seriously by NP. By environmental selection pressure method in high NP concentration media, ten strains was purified as targets which could degrade NP. Four strains were selected to study, and named as NPF-1, NPF-2, NPF-3 and NPF-4, respectively. The contents of NP before and after fungi degradation were analysed by GC chromatography. The various environmental factors influencing the NP degradation were investigated. The possible degradation pathways were estabolished by NP biodegradation metabolites. The mainresults were as follows:（1） The target fungi were identified as Aspergillus niger strain WA0000009398, Aspergillus terreus isolate MD11₂（1）, Aspergillus terreus strain SHPP01 and Penicillium simplicissimum strain PS1 according to their morphology and 18S rDNA sequence.（2） For all for strains, the most suitable medium was suggested as PD medium by growth mass,4-n-NP removal and degradation study. The growth mass of NPF-2, NPF-3 and NPF-4 in 60% seawater medium were lower than the freshwater, but NPF-1 showed opposite result. The removal and degradation rates of NPF-1, NPF-2 and NPF-3 in 60% seawater medium were higher than the freshwater, but NPF-4 showed opposite result. All strains showed higher mass growth,4-n-NP removal and degradation rate in dynamic culture than in static culture. The concentration effects of initial 4-n-NP on strain mass growth and degradation results showed inverse relationship except NPF-4.（3） The initial 4-n-NP concentration （<100 mg-L1） showed irrelevant in NPF-4 mass growth. But it still followed the role of lower initial concentration, higher degradation rate. The glucose adding could significantly the biomass increasing of NPF-4 and the removal rate raise of 4-n-NP. The mixture culture of NPF-1, NPF-2 and NPF-3 to NPF-4 results showed higher removal and degradation rate, respectively. It suggested that was synergistic action between each two strains.（4） The suitable condition was suggested as 60% seawater PD media,4-n-NP 20 mg-L’1 and dynamic culture. The strain mass growth and 4-n-NP removal and degradation ability were studied. All the strains had a rapid growth in the first five days, then stable and gradually died. The 4-n-NP removal could basically reach to 100% in 3 d. But the 4-n-NP degradation rate was different. It was the fastest in NPF-1,82.90% in Id,92.46% in 3d and completely in 5d, respectly. The degradation rate of NPF-1 and NPF-2 was higher than NPF-3 and NPF-4.（5） The 4-n-NP degradation metabolites of NPF-1 were analysised by LC-MS. Fourteen products were identified as 4-n-NP related compounds by mass spectra and relevant literatures. Three probable biodegradation pathways of 4-n-NP were proposed.