Toccalino P L, Johnson R L, Boone D R
Department of Environmental Science and Engineering, Oregon Graduate Institute of Science & Technology, Portland 97291-1000.
Appl Environ Microbiol. 1993 Sep;59(9):2977-83. doi: 10.1128/aem.59.9.2977-2983.1993.
We investigated nutrient limitations during hydrocarbon degradation in a sandy soil and found that fixed nitrogen was initially a limiting nutrient but that N limitation could sometimes be overcome by N2 fixation. Hydrocarbon biodegradation was examined in an unsaturated sandy soil incubated aerobically at 20 degrees C with propane or butane and various added nutrients. Propane and butane degradation proceeded similarly during the first 3 months of incubation. That is, bacteria in soil amended with N oxidized these hydrocarbons more rapidly than in controls without nutrient additions or in soil with added phosphate or trace minerals. Both propane- and butane-amended soil apparently became N limited after the initial available inorganic N was utilized, as indicated by a decrease in the rates of hydrocarbon degradation. After 3 months, propane and butane degradation proceeded differently. Bacteria in propane-degrading soil apparently remained N limited because propane degradation rates stayed low unless more N was added. In contrast, bacteria in butane-degrading soil appeared to overcome their N limitation because butane degradation rates later increased regardless of whether more N was added. Analyses of total N and acetylene reduction assays supported this apparent surplus of N in butane-amended soil. Total N was significantly (P < 0.01) higher in soil incubated with butane and no N amendments than in soil incubated with propane, even when the latter was amended with N. Acetylene reduction occurred only in butane-amended soil. These results indicate that N2 fixation occurred in butane-amended soil but not in propane-amended soil.
我们研究了砂质土壤中烃类降解过程中的养分限制，发现固定态氮最初是一种限制养分，但有时通过固氮作用可以克服氮限制。在不饱和砂质土壤中，于20摄氏度下有氧培养丙烷或丁烷并添加各种养分，对烃类生物降解进行了研究。在培养的前3个月，丙烷和丁烷的降解过程相似。也就是说，添加氮的土壤中的细菌比未添加养分的对照土壤或添加了磷酸盐或微量矿物质的土壤中的细菌更快速地氧化这些烃类。在最初的有效无机氮被利用后，添加丙烷和丁烷的土壤显然都变成了氮限制状态，这表现为烃类降解速率下降。3个月后，丙烷和丁烷的降解情况有所不同。降解丙烷的土壤中的细菌显然仍然处于氮限制状态，因为除非添加更多的氮，丙烷降解速率仍然很低。相比之下，降解丁烷的土壤中的细菌似乎克服了它们的氮限制，因为无论是否添加更多的氮，丁烷降解速率后来都增加了。对总氮的分析和乙炔还原试验支持了添加丁烷的土壤中明显存在氮过剩的情况。与丙烷培养的土壤相比，即使丙烷培养的土壤添加了氮，在不添加氮的情况下培养丁烷的土壤中的总氮显著更高（P < 0.01）。乙炔还原只发生在添加丁烷的土壤中。这些结果表明，添加丁烷的土壤中发生了固氮作用，而添加丙烷的土壤中没有。
