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Abstract
To recover a nitrogen resource from high-ammonia-nitrogen wastewater, two amphitrophic hydrogen-oxidizing bacteria (HOB), Paracoccus denitrificans Y5 and P. versutus D6, capable of nitrogen assimilation for single-cell protein (SCP) production were isolated. These two HOB strains could grow autotrophically with H2 as an electron donor, O2 as an electron acceptor, CO2 as a carbon source, and ammonia nitrogen (NH4+-N) as a nitrogen source. The cell molecular formulas of strains Y5 and D6 determined by autotrophic cultivation were C3.33H6.83O2.58N0.77 and C2.87H5.34O3.17N0.57, respectively. The isolated strains could synchronously remove NH4+-N and organic carbon and produce SCP via heterotrophic cultivation. The rates of removal of NH4+-N and soluble chemical oxygen demand reached 35.47 and 49.04%, respectively, for Y5 under mixotrophic cultivation conditions with biogas slurry as a substrate. SCP content of strains Y5 and D6 was 67.34–73.73% based on cell dry weight. Compared with soybean meal, the SCP of Y5 contained a variety of amino acids.
Details
1 Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, People’s Republic of China; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, People’s Republic of China
2 Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, People’s Republic of China
3 School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, People’s Republic of China