β‐Nicotinamide mononucleotide (NMN) has recently gained attention for a nutritional supplement because it is an intermediate in the biosynthesis of nicotinamide adenine dinucleotide (NAD+). In this study, we developed NMN synthesis by coupling two modules. The first module is to culture E. coli MG1655 ▵tktA ▵tktB ▵ptsG to metabolize xylose to generate D‐ribose in the medium. The supernatant containing D‐ribose was applied in the second module which is composed of EcRbsK‐EcPRPS‐CpNAMPT reaction to synthesize NMN, that requires additional enzymes of CHU0107 and EcPPase to remove feedback inhibitors ADP and pyrophosphate. The second module can be rapidly optimized by comparing NMN production determined by the cyanide assay. Finally, 10 mL optimal biocascade reaction generated NMN with a good yield of 84 % from 1 mM D‐ribose supplied from the supernatant of E. coli MG1655 ▵tktA ▵tktB ▵ptsG. Our results can further guide researchers to metabolically engineer E. coli for NMN synthesis.

A new chalcone-based fluorescent turn-on probe (3c) responsive to the nitroreductase (NTR) activity and its application toward the detection of bacteria are presented. The probe exhibits turn-on fluorescence at 535...

Fluorescence-based techniques are essential for the analysis of nucleic acids. Two readily obtainable small cationic dyes with increased fluorescence following non-covalent DNA binding showed selectivity for Gram-negative bacteria and cancer cells.

A fatty aldehyde surrogate containing a formyl thioester group can be reduced by fatty aldehyde reductase (FALR) with stoichiometric formaldehyde generation. It can be rapidly visualized and quantified using the Purpald assay for screening applications.