'CONSTRUCTION OF BIOSENSOR (DEAD CELLS BASED) FOR MONITORING SILVERIONS IN THE INDUSTRIAL EFFLUENT'

摘要

It has been found that Biosensor can monitor silver ions in the concentration range of 36 ppb to 1000 ppb in the industrial effluent. For that Saccharomyces cerevisae containing extracellular enzyme invertase was cultured, then harvested and immobilized in calcium alginate matrix. The immobilized cell biomass was coupled to the RTD probe with the help of nylon membrane using rubber string. So cell based electrode was constructed and RTD probe was dipped in to the soluton containing sucrose as substrate at pH 5.5 for 30 minutes. The extracellular enzyme invertase present in cell biomass hydrolyzed the sucrose in to glucose and fructose and there wsa rise in temperature which could be recorded by digital meter. Differnt concentrations of silver ions were added each time and there was decrease in rise in temperature with increase in silver ions concentrations because of inhibition of enzyme activity. For that standard curve was constructed by plotting a graph between % inhibition and silver ions concentration. From the standard curve the concentration of silver ions in the industrial effluent can be monitored. The interference of other cations if present can be masked by DPTA. The Biosensor can be regenerated by dipping it into 1M sodium thiosulphate solution and is reusable, stable for 1 week if kept at 4°C in referigerator. 10 assays are possible. The reliability of the developed Biosensor has been checked by adding known amount of silver ions in the industrial effluent and also by using chemical sensor.