Engineered Bacterium DF4-8 Achieves Specific Phenol Detection via a unique mopR-like Regulatory Pathway

The engineered Acinetobacter sp. strain DF4-8 demonstrates exceptional bioluminescent detection capabilities for phenol, showcasing its potential as a highly specific environmental biosensor. A novel mopR-like gene within DF4-8, distinct from known mopR genes, points to a unique regulatory pathway governing phenol-induced bioluminescence. Genomic analysis uncovers a complex mopR-like gene region in DF4-8, featuring distinct ORFs and promoters compared to its bioluminescence-negative counterpart, DF4-10. Each ORF exhibits a unique predicted protein structure and harbors novel motifs, with DF4-ORF8 notably carrying a discovered NAD-binding motif (EKRDQVLSLITATA). Co-factor analysis reveals a potential NAD-binding domain (QATKVGVLGAGMMGADVTKWQATKVGVLGAGMMGA) within DF4-ORF8, suggesting its dual functionality in metabolic pathways and phenol recognition. Further exploration of specific regulatory factors, such as ArgR for mopR-ORF, PhoB for DF4-ORF8, and RpoD17 for DF4-ORF10, is crucial for understanding this intricate regulatory network. The study also hints at a potential role of transposable elements (Tn elements) in explaining the dissimilarity among DF4-8, the mopR-like gene, and DF4-10 DNA sequences. These findings shed light on a previously undescribed regulatory pathway governing phenol-induced bioluminescence in DF4-8, unveiling a promising biosensor with enhanced detection specificity and opening avenues for further exploration of the intricate regulatory mechanisms within the mopR-like gene region.