Mergaert J, Boley A, Cnockaert M C, Müller W R, Swings J
Laboratorium voor Microbiologie, Vakgroep Biochemie, Fysiologie en Microbiologie, Universiteit Gent, Belgium.
Syst Appl Microbiol. 2001 Jul;24(2):303-10. doi: 10.1078/0723-2020-00037.
A collection of 186 heterotrophic bacteria, isolated directly from a continuous-upflow fixed-bed reactor for the denitrification of drinking water, in which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) granules acted as biofilm carrier, carbon source and electron donor, was studied with regard to taxonomic affiliation and degradation and denitrification characteristics. Two granule samples were taken from a fully operating reactor for enumeration and isolation of heterotrophic bacteria. One sample was drawn from the lower part of the reactor, near the oxic zone, and the other sample from the upper, anoxic part of the fixed bed. Dominant colonies were isolated and the cultures were identified using fatty acid analysis and 16S rDNA sequencing. Their ability to degrade the polymer and 3-hydroxybutyrate and to denitrify in pure culture was assessed. The results show that high numbers of heterotrophic bacteria were present in the biofilms on the polymer granules, with marked differences in taxonomic composition and potential functions between the lower and upper part of the fixed bed. The majority of the isolates were Gram negative bacteria, and most of them were able to reduce nitrate to nitrite or to denitrify, and to utilize 3-hydroxybutyrate as sole source of carbon. Only two groups, one identified as Acidovorax facilis and the other phylogenetically related to Brevundimonas intermedia, could combine denitrification and utilization of poly(3-hydroxybutyrate) (PHB), and were found only in the upper sample. The other groups occurred either in the lower or upper part, or in both samples. They were assigned to Brevundimonas, Pseudomonas, Agrobacterium, Achromobacter, or Phyllobacterium, or were phylogenetically related to Afipia or Stenotrophomonas.
从用于饮用水反硝化的连续上流式固定床反应器中直接分离出186株异养细菌，该反应器中聚（3-羟基丁酸酯-co-3-羟基戊酸酯）（PHBV）颗粒用作生物膜载体、碳源和电子供体，对这些细菌进行了分类归属以及降解和反硝化特性研究。从一个完全运行的反应器中采集了两个颗粒样品，用于异养细菌的计数和分离。一个样品取自反应器下部靠近好氧区的位置，另一个样品取自固定床上部的缺氧部分。分离出优势菌落，并使用脂肪酸分析和16S rDNA测序对培养物进行鉴定。评估了它们在纯培养物中降解聚合物和3-羟基丁酸酯以及反硝化的能力。结果表明，聚合物颗粒上的生物膜中存在大量异养细菌，固定床上下部的分类组成和潜在功能存在显著差异。大多数分离株为革兰氏阴性菌，其中大多数能够将硝酸盐还原为亚硝酸盐或进行反硝化，并将3-羟基丁酸酯用作唯一碳源。只有两组，一组鉴定为食酸嗜酸菌，另一组在系统发育上与中间短波单胞菌相关，能够将反硝化作用与聚（3-羟基丁酸酯）（PHB）的利用相结合，且仅在上部样品中发现。其他组要么出现在下部，要么出现在上部，或者在两个样品中都有。它们被归类为短波单胞菌属、假单胞菌属、土壤杆菌属、无色杆菌属或叶杆菌属，或者在系统发育上与阿菲比菌属或嗜麦芽窄食单胞菌相关。
