Partitioning studies of l-glutaminase production by Bacillus cereus MTCC 1305 in different PEG-salt/dextran

Abstract

Partitioning studies of l-glutaminase production by Bacillus cereus MTCC 1305 was carried out in different PEG-salt/PEG-dextran system. The partitioning value of l-glutaminase increased with increasing molecular weight of PEG from 2000-4000. kDa and decreased with higher molecular weight of 6000. kDa. Phase system of PEG 4000 (8.5%)/dextran T500 (9.5%) was selected for the extractive fermentative production of l-glutaminase on the basis maximum partition coefficient (1.31). The production of l-glutaminase was found higher in top phase of ATPS (2.09. U/ml) than control media (1.42. U/ml). Overall production of l-glutaminase (1.83. U/ml) was found lower than top phase (2.09. U/ml) in ATPS system. The growth profile with short lag phase and higher cell concentration was obtained for ATPS. The partition coefficient of l-glutaminase increased with increase of system pH and temperature and optimum production was obtained at pH 7.5 and temperature 30 °C in top phase of PEG 4000/dextran T500 system. © 2012 Elsevier Ltd.