Application of biopolymer produced from metabolic engineeredAcinetobactersp. for the development of phosphate optoelectronic sensor

In this study, we report the development of a phosphate sensor by exploiting phosphate-binding capability of Acinetobacter sp. biopolymer. An engineered strain of Acinetobacter sp. overproducing biopolymer was selected by Tn5 mutagenesis. The mutant showed a five-fold increase in biopolymer production and an increase in expression of intracellular biopolymer synthetic enzymes, phosphoglucomutase and glucosyl transferase. Physical and chemical analysis of biopolymer revealed a porous, compact surface morphology and a polysaccharide structure with predominance of uronic acid residues. Cellulose acetate membranes precoated with purified biopolymer were exposed to phosphate solutions and membrane-bound phosphate was determined by stannous chloride method. The colored membranes were analyzed by a LED (690 nm)/photodiode detection system. The phosphate concentration was estimated by converting the amperometric signal to phosphate concentrations from a standard plot. In conclusion, we anticipate that the developed sensor could be used for on-site phosphate analysis due to its compactness, portability, low detection levels (1 μg L−1), and low power consumption.