Removal of Nitrate Nitrogen by Rhodotorula graminis Immobilized in Alginate Gel for Groundwater Treatment

Groundwater is the source of all tap water in Kumamoto City, Japan. However, concentration nitrate nitrogen (NO3−-N) tends to increase every year due influences overfertilization, field disposal livestock manure, and inflow domestic wastewater. A heterotrophic nitrification–aerobic denitrification (HN-AD) system an attractive approach for nitrate-nitrogen removal. In this study, Rhodotorula graminis NBRC0190, a naturally occurring red yeast that shows high removal performance glucose, was immobilized on calcium alginate hydrogel beads. NO3−-N efficiency exceeded 98% region below 10 mg/L model groundwater. Even after same treatment repeated five times, R. gra beads maintained. Finally, when method applied actual groundwater it possible make even higher quality.