Nitrate reduction by Paracoccus thiophilus strain LSL 251 under aerobic condition: Performance and intracellular central carbon flux pathways

Shengnan Chen; Sulin Li; Tinglin Huang; Shangye Yang; Kaiwen Liu; Ben Ma; Yinjie Shi; Yutian Miao

doi:10.1016/j.biortech.2020.123301

Nitrate reduction by Paracoccus thiophilus strain LSL 251 under aerobic condition: Performance and intracellular central carbon flux pathways

Bioresour Technol. 2020 Jul:308:123301. doi: 10.1016/j.biortech.2020.123301. Epub 2020 Apr 5.

Authors

Shengnan Chen¹, Sulin Li², Tinglin Huang², Shangye Yang², Kaiwen Liu², Ben Ma², Yinjie Shi², Yutian Miao²

Affiliations

¹ Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: chenshengnan@xauat.edu.cn.
² Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.

PMID: 32299051
DOI: 10.1016/j.biortech.2020.123301

Abstract

The intracellular carbon metabolic flux pathways of denitrifying bacteria under aerobic conditions remain unclear. Here, a newly strain LSL251 was identified as Paracoccus thiophilus. Strain LSL251 removed 94.79% and 98.78% of total organic carbon and nitrate. 74.66% of nitrogen in culture system was lost as gaseous nitrogen. Moreover, ¹³C stable isotopic labeling and metabolic flux analyses revealed that the primary intracellular carbon metabolic pathways were the Entner-Doudoroff pathway and the tricarboxylic acid (TCA) cycle. Electrons are primarily donated as direct electron donor-NADH through the TCA cycle. Furthermore, response surface methodology modeled that the highest total nitrogen removal efficiency was 98.43%, where the optimal parameters were C/N ratio of 8.00, 32.98 °C, 50.18 rpm, and initial pH of 7.73. All together, these results have shed new lights on intracellular central carbon metabolic distribution and flux pathways of aerobic denitrifying bacteria.

Keywords: (13)C-MFA; Aerobic denitrification; Carbon metabolic distribution; Paracoccus thiophilus.

MeSH terms

Aerobiosis
Carbon
Carbon Cycle
Denitrification
Nitrates
Nitrogen
Paracoccus*

Substances

Nitrates
Carbon
Nitrogen

Supplementary concepts

Paracoccus thiophilus