Development of carbon monoxide-tolerant fluorescent reporter system functional under anoxic conditions in Eubacterium callanderi KIST612

  • Bioresour Technol. 2025 Nov 30:442:133752. doi: 10.1016/j.biortech.2025.133752.
Tantri Ardiwinata  1 ,  Byeongchan Kang  2 ,  Ji-Yeon Kim  2 ,  Soyoung Oh  2 ,  In Seop Chang  3
Affiliations
  • 1. Department of Environment and Energy Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea.
  • 2. Department of Environment and Energy Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea.
  • 3. Department of Environment and Energy Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea. Electronic address: [email protected].
PMID: 41330450 DOI: 10.1016/j.biortech.2025.133752
Abstract

This study aimed to develop a fluorescent reporter system optimized for acetogen Eubacterium callanderi KIST612, addressing key challenges such as autofluorescence and CO exposure. To support reporter selection, autofluorescence in E. callanderi KIST612 was characterized. Fluorescence-activating and absorption-shifting tags (FAST), particularly FAST1-HMBR, was identified as the most suitable candidate due to its spectral properties, kinetics, and compatibility with the anaerobic strain. Under strict anoxic environments, FAST1-expressing strains exhibited significantly greater fluorescence intensity than controls-4.55-fold in glucose and 4.54-fold in CO conditions. Functional validation using a CO-sensing system showed a proportional increase in fluorescence intensity with the increasing CO partial pressure (R2, 0.97), confirming the system's sensitivity and capability in anaerobic CO conditions.

Keywords
Acetogen; Anaerobic reporter system; Autofluorescence; Carbon monoxide; Eubacterium callanderi KIST612.
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