Selection of an apt support for the immobilization of microbes for the development of a BOD biosensor

The present study entails the screening of different supports for the immobilization of a bacterial consortium for the development of a BOD biosensor. The supports used were PVA (polyvinyl alcohol) + nylon cloth, agarose, nitrocellulose and a nylon membrane. The stability of the prepared membranes was checked at regular time intervals in terms of their response with a reference standard, i.e. glucose–glutamic acid, while stored at different temperatures as well as at different pH values. It was observed that microbes immobilized on the nylon membrane exhibited a maximum stability compared to those immobilized on the other membranes. The study revealed that pH 7.0 was best suited for the storage of membranes harboring immobilized bacteria, preferably at 4 °C, with an observed stability of more than 400 days. Studies also showed that leaching was negligible in the case of a charged nylon membrane. The selected support material, i.e. the immobilized microbial nylon membrane, maintained its stability and activity after an intermittent use for 400 cycles.