Our research develops an economical and efficient formaldehyde detector which turns red in the presence of formaldehyde, offering a visual indicator using the ΔfrmR strain of Escherichia. coli. The detector incorporates frmA and frmB genes to remediate formaldehyde in the solution, assuring its reusability when provided with sufficient nutrients. This innovative approach promises a reliable and reusable solution for formaldehyde detection, addressing a critical need for safety and health protection.