Department of Environmental Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Pusan, South Korea.
Department of Systems Biotechnology, Chung-Ang University, 4726 Seodongdae-ro Daeduckmyun, Anseong, South Korea.
World J Microbiol Biotechnol. 2019 Sep 23;35(10):149. doi: 10.1007/s11274-019-2716-8.
The goal of this study was to investigate the relationship between the denitrification process and carbon metabolism in a full-scale tannery wastewater treatment plant bioaugmented with the microbial consortium BM-S-1. The metagenomic analysis of the microbial community showed that Brachymonas denitrificans, a known denitrifier, was present at a high level in the treatment stages of buffering (B), primary aeration (PA), and sludge digestion (SD). The occurrences of the amino acid-degrading enzymes alpha ketoglutarate dehydrogenase (α-KGDH) and tryptophan synthase were highly correlated with the presence of denitrification genes, such as napA, narG, nosZ and norB. The occurrence of glutamate dehydrogenase (GDH) was also highly paralleled with the occurrence of denitrification genes such as napA, narG, and norZ. The denitrification genes (nosZ, narG, napA, norB and nrfA) and amino acid degradation enzymes (tryptophan synthase, α-KGDH and pyridoxal phosphate dependent enzymes) were observed at high levels in B. This indicates that degradation of amino acids and denitrification of nitrate may potentially occur in B. The high concentrations of the fatty acid degradation enzyme groups (enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase and β-ketothiolase) were observed together with the denitrification genes, such as napA, narG and nosZ. Phospholipase/carboxylesterase, enoyl-CoA hydratase/isomerase, acyl-CoA dehydrogenase, phenylacetate degradation enzyme and 3-hydroxyacyl-CoA dehydrogenase 2 were also dominant in B. All these results clearly indicate that the denitrification pathways are potentially linked to the degradation pathways of amino acids and fatty acids whose degradation products go through the TCA cycle, generating the NADH that is used as electron donors for denitrification.
本研究旨在探究在规模化制革废水处理厂中添加微生物联合体 BM-S-1 后，反硝化过程与碳代谢之间的关系。微生物群落的宏基因组分析表明，已知的反硝化菌 Brachymonas denitrificans 在缓冲池（B）、初级曝气池（PA）和污泥消化池（SD）等处理阶段的丰度较高。氨基酸降解酶α-酮戊二酸脱氢酶（α-KGDH）和色氨酸合酶的出现与反硝化基因如 napA、narG、nosZ 和 norB 的存在高度相关。谷氨酸脱氢酶（GDH）的出现也与 napA、narG 和 norZ 等反硝化基因高度平行。nosZ、narG、napA、norB 和 nrfA 等反硝化基因和氨基酸降解酶（色氨酸合酶、α-KGDH 和吡哆醛磷酸依赖酶）在 B 中均高度存在。这表明氨基酸的降解和硝酸盐的反硝化可能在 B 中发生。高浓度的脂肪酸降解酶群（烯酰-CoA 水合酶、3-羟基酰基-CoA 脱氢酶和β-酮硫解酶）与 napA、narG 和 nosZ 等反硝化基因一起存在。磷脂酶/羧酸酯酶、烯酰-CoA 水合酶/异构酶、酰基辅酶 A 脱氢酶、苯乙酸降解酶和 3-羟基酰基-CoA 脱氢酶 2 在 B 中也占主导地位。所有这些结果清楚地表明，反硝化途径可能与氨基酸和脂肪酸的降解途径有关，其降解产物通过 TCA 循环，生成用于反硝化的 NADH 作为电子供体。
