Increased acid resistance of the archaeon, Metallosphaera sedula by adaptive laboratory evolution

Chenbing Ai, Samuel McCarthy, Valerie Eckrich, Deepak Rudrappa, Guanzhou Qiu, Paul Blum

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Extremely thermoacidophilic members of the Archaea such as the lithoautotroph, Metallosphaera sedula, are among the most acid resistant forms of life and are of great relevance in bioleaching. Here, adaptive laboratory evolution was used to enhance the acid resistance of this organism while genomics and transcriptomics were used in an effort to understand the molecular basis for this trait. Unlike the parental strain, the evolved derivative, M. sedula SARC-M1, grew well at pH of 0.90. Enargite (Cu3AsS4) bioleaching conducted at pH 1.20 demonstrated SARC-M1 leached 23.78 % more copper relative to the parental strain. Genome re-sequencing identified two mutations in SARC-M1 including a nonsynonymous mutation in Msed_0408 (an amino acid permease) and a deletion in pseudogene Msed_1517. Transcriptomic studies by RNA-seq of wild type and evolved strains at various low pH values demonstrated there was enhanced expression of genes in M. sedula SARC-M1 encoding membrane complexes and enzymes that extrude protons or that catalyze proton-consuming reactions. In addition, M. sedula SARC-M1 exhibited reduced expression of genes encoding enzymes that catalyze proton-generating reactions. These unique genomic and transcriptomic features support a model for increased acid resistance arising from enhanced control over cytoplasmic pH.

Original languageEnglish (US)
Pages (from-to)1455-1465
Number of pages11
JournalJournal of Industrial Microbiology and Biotechnology
Issue number10
StatePublished - Oct 1 2016


  • Acidity resistance
  • Enargite bioleaching
  • Genome re-sequencing
  • Metallosphaera sedula
  • RNA sequencing
  • Transcriptional responses

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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