Nondestructive Chemical Sensing within Bulk Soil Using 1000 Biosensors per Gram of Matrix

Emily M. Fulk, Xiaodong Gao, Li Chieh Lu, Kelly R. Redeker, Caroline A. Masiello, Jonathan J. Silberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Gene expression can be monitored in hard-To-image environmental materials using gas-reporting biosensors, but these outputs have only been applied in autoclaved matrices that are hydrated with rich medium. To better understand the compatibility of indicator gas reporting with environmental samples, we evaluated how matrix hydration affects the gas signal of an engineered microbe added to a sieved soil. A gas-reporting microbe presented a gas signal in a forest soil (Alfisol) when hydrated to an environmentally relevant osmotic pressure. When the gas signal was concentrated prior to analysis, a biosensor titer of 103cells/gram of soil produced a significant signal when soil was supplemented with halides. A signal was also observed without halide amendment, but a higher cell titer (106cells/gram of soil) was required. A sugar-regulated gas biosensor was able to report with a similar level of sensitivity when added to an unsterilized soil matrix, illustrating how gas concentration enables biosensing within a soil containing environmental microbes. These results establish conditions where engineered microbes can report on gene expression in living environmental matrices with decreased perturbation of the soil environment compared to previously reported approaches, using biosensor titers that are orders of magnitude lower than the number of cells typically observed in a gram of soil.

Original languageEnglish
Pages (from-to)2372-2383
Number of pages12
JournalACS Synthetic Biology
Issue number7
Early online date17 Jun 2022
Publication statusPublished - 15 Jul 2022


  • biosensor
  • gas reporter
  • material
  • microbe
  • sediment
  • soil
  • synthetic biology

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