Bioprocess and medium optimization for glutamic acid production using submerged fermentation in shake flask and bioreactor

Abstract

The current research was designed to enhance glutamic acid production by screening five different microbial strains (Microbacterium ammoniaphilum. Brevibacterium divaricatum nov. sp., Micrococcus glutamicus.nov. sp., Brevibacterium flavum nov. sp., Brevibacterium aminogenes nov. sp.) and followed by optimization process. All strains were able to produced glutamic acid but at specific production yield. Micrococcus glutamicus nov. was observed to be the most suitable for glutamic acid production. Five different carbon sources (glucose, mannitol, sucrose, maltose, maltodextrin) and five different nitrogen sources (ammonium chloride, urea, potassium nitrate, casein and sodium nitrate) were screened and optimized. Maltodexrin was determine for the most favorable carbon source for glutamic acid production with optimal concentration of 3g/L while ammonium chloride was determine for the most efficient nitrogen source for glutamic acid production with optimal concentration of 4g/L. The optimal temperature obtained was at 30°C for glutamic acid production (4.75 g/L). In bioreactor, 7.75 g/L of glutamic acid production was achieved with total acidity of 6.3 g/L and cell dry weight of 7 g/L.