Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA.
BioTechnology Institute, University of Minnesota, St. Paul, MN, USA.
J Appl Microbiol. 2020 Sep;129(3):590-600. doi: 10.1111/jam.14655. Epub 2020 Apr 24.
This study was done to obtain denitrifiers that could be used for bioaugmentation in woodchip bioreactors to remove nitrate from agricultural subsurface drainage water.
We isolated denitrifiers from four different bioreactors in Minnesota, and characterized the strains by measuring their denitrification rates and analysing their whole genomes. A total of 206 bacteria were isolated from woodchips and thick biofilms (bioslimes) that formed in the bioreactors, 76 of which were able to reduce nitrate at 15°C. Among those, nine potential denitrifying strains were identified, all of which were isolated from the woodchip samples. Although many nitrate-reducing strains were isolated from the bioslime samples, none were categorized as denitrifiers but instead as carrying out dissimilatory nitrate reduction to ammonium.
Among the denitrifiers confirmed by N stable isotope analysis and genome analysis, Cellulomonas cellasea strain WB94 and Microvirgula aerodenitrificans strain BE2.4 appear to be promising for bioreactor bioaugmentation due to their potential for both aerobic and anaerobic denitrification, and the ability of strain WB94 to degrade cellulose.
Denitrifiers isolated in this study could be useful for bioaugmentation application to enhance nitrate removal in woodchip bioreactors.
本研究旨在获得可用于生物强化的反硝化菌，用于从农业地下排水中去除硝酸盐。
我们从明尼苏达州的四个不同的生物反应器中分离出反硝化菌，并通过测量其反硝化速率和分析其全基因组来表征这些菌株。从木屑和在生物反应器中形成的厚生物膜（生物泥）中总共分离出 206 株细菌，其中 76 株能够在 15°C 下还原硝酸盐。其中，鉴定出了 9 株有潜力的反硝化菌株，均从木屑样本中分离得到。尽管从生物泥样本中分离出了许多硝酸盐还原菌株，但它们都不属于反硝化菌，而是进行异化硝酸盐还原为铵。
通过氮稳定同位素分析和基因组分析证实的反硝化菌中，Cellulomonas cellasea 菌株 WB94 和 Microvirgula aerodenitrificans 菌株 BE2.4 似乎因其具有好氧和厌氧反硝化的潜力以及菌株 WB94 降解纤维素的能力，有望用于生物反应器的生物强化。
本研究中分离出的反硝化菌可用于生物强化应用，以增强木屑生物反应器中硝酸盐的去除。
