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Journal of Desert Research ›› 2025, Vol. 45 ›› Issue (5): 217-229.DOI: 10.7522/j.issn.1000-694X.2025.00119

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Screening, identification and carbon fixation capacity assessment of chemolithoautotrophic microorganisms in biological soil crusts of Mu Us Sandy Land

Guangwei Zhao1(), Xiangwen Niu5, Cunlin Bai5, Yanrong Meng1, Yuqing Zhang1,3,4, Shugao Qin2, Weiwei She2, Wei Feng2()   

  1. 1.Yanchi Research Station /, Ministry of Education,Beijing Forestry University,Beijing 100083,China
    2.State Key Laboratory of Efficient Production of Forest Resource /, Ministry of Education,Beijing Forestry University,Beijing 100083,China
    3.National Engineering Research Center for Tree Breeding and Ecological Restoration /, Ministry of Education,Beijing Forestry University,Beijing 100083,China
    4.Key Laboratory of National Forestry and Grassland Administration on Soil and Water Conservation /, Ministry of Education,Beijing Forestry University,Beijing 100083,China
    5.Engineering Research Center of Forestry Ecological Engineering, Ministry of Education,Beijing Forestry University,Beijing 100083,China
    6.Administrative Bureau of Ningxia Haba Lake National Nature Reserve,Yanchi 751500,Ningxia,China
  • Received:2025-02-11 Revised:2025-05-15 Online:2025-09-20 Published:2025-09-27
  • Contact: Wei Feng

Abstract:

To explore the types and physicochemical characteristics of culturable chemoautotrophic microorganisms in the biological crusts of the Mu Us Sandy Land and to screen out strains with high carbon fixation capacity and potential application value, this study used an inorganic medium without carbon sources and obtained stable carbon-fixing strains through continuous separation and subculture for 9 generations. Based on morphological characteristics, growth characteristics, physiological and biochemical characteristics, and 16S rDNA sequence analysis, the carbon-fixing strains were systematically identified. The carbon fixation pathways and carbon fixation efficiency of the strains were further analyzed by measuring the activities of key carbon fixation enzymes (ATP-citrate lyase (ACLY) and ribulose-1,5-bisphosphate carboxylase (RubisCO)), organic carbon content, and gel electrophoresis of carbon fixation functional genes in the bacterial culture. The results showed that a total of 18 chemoautotrophic strains were screened from the biological crust samples, belonging to Streptomyces (10 strains), Saccharothrix (3 strains), RhodococcusMethylobacteriumArthrobacterActinoplanes, and Acinetobacter (1 strain each). Among them, the carbon fixation function of Saccharothrix and Actinoplanes bacteria was verified for the first time, and it was found that the same strain could achieve carbon fixation through multiple pathways. In terms of carbon fixation capacity, strains 3, 5, and 14 of Streptomyces and strain 2 of Methylobacterium showed high organic carbon accumulation capacity, with organic carbon contents of 57.82, 58.21, 62.89 mg·L-1, and 65.94 mg·L-1, respectively, and accompanied by significant hydrolytic activity, indicating that these strains have potential application value as microbial agents for soil improvement and ecological restoration in desert areas. This study not only expanded the cognitive boundary of microbial carbon sink function in arid areas but also provided new functional bacterial resources for the regulation of biogeochemical cycles in desert ecosystems.

Key words: Mu Us Sandy Land, biological crust, carbon-fixing enzyme, organic carbon content, chemoautotrophic strains

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