Propionibacterium freudenreichii-Assisted Approach Reduces N2O Emission and Improves Denitrification via Promoting Substrate Uptake and Metabolism.
Propionibacterium freudenreichii-Assisted Approach Reduces N2O Emission and Improves Denitrification via Promoting Substrate Uptake and Metabolism.
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DOI：
10.1021/acs.est.2c05674
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发表时间：
2022-11
影响因子：
11.4
通讯作者：
Meirou Wu;Zhiqi Zhang;Xin Zhang;Lei Dong;Chao Liu;Yinguang Chen
中科院分区：
文献类型：
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作者：
Meirou Wu;Zhiqi Zhang;Xin Zhang;Lei Dong;Chao Liu;Yinguang Chen
N2O排放是生物反硝化过程中经常遇到的问题。本文报道了一种利用微生物促进底物吸收和代谢以减少反硝化中间体积累的新方法。在生物反硝化系统中引入弗氏丙酸菌，当弗氏丙酸菌/地下水反硝化剂OD600为1/5时，24 h内N2O和亚硝酸盐积累量分别减少了74%和60%，反硝化效率提高了150%。丙酸只加速硝酸盐的去除，而不是中间积累减少的主要原因。蛋白质组学和酶学分析表明，P. freudenreichii通过上调参与孔蛋白形成、腐胺生物合成、亚精胺/腐胺运输和群体感应的蛋白质，促进了碳源、硝酸盐、铁和钼（反硝化酶所需的催化位点）的吸收，从而刺激了生物膜的形成。进一步研究发现，P. freudenreichii激活了反硝化菌中的甲基丙二酰辅酶a通路，促进其合成血红素/血红素d1、反硝化酶基团和电子转移蛋白，从而上调反硝化酶蛋白的表达，提高NosZ与NorB的比值，导致生物反硝化过程中电子的产生、转移和消耗增加。因此，反硝化中间体积累显著减少，反硝化效率显著提高。
N2O emission is often encountered during biodenitrification. In this paper, a new approach of using microorganisms to promote substrate uptake and metabolism to reduce denitrification intermediate accumulation was reported. With the introduction of Propionibacterium freudenreichii to a biodenitrification system, N2O and nitrite accumulation was, respectively, decreased by 74 and 60% and the denitrification efficiency was increased by 150% at the time of 24 h with P. freudenreichii/groundwater denitrifier of 1/5 (OD600). Propionate, produced by P. freudenreichii, only accelerated nitrate removal and was not the main reason for the decreased intermediate accumulation. The proteomic and enzyme analyses revealed that P. freudenreichii stimulated biofilm formation by upregulating proteins involved in porin forming, putrescine biosynthesis, spermidine/putrescine transport, and quorum sensing and upregulated transport proteins, which facilitated the uptake of the carbon source, nitrate, and Fe and Mo (the required catalytic sites of denitrification enzymes). Further investigation revealed that P. freudenreichii activated the methylmalonyl-CoA pathway in the denitrifier and promoted it to synthesize heme/heme d1, the groups of denitrification enzymes and electron transfer proteins, which upregulated the expression of denitrifying enzyme proteins and enhanced the ratio of NosZ to NorB, resulting in the increase of generation, transfer, and consumption of electrons in biodenitrification. Therefore, a significant reduction in the denitrification intermediate accumulation and an improvement in the denitrification efficiency were observed.