To improve the acrylamide-tolerance of Nocardia sp.

acrylonitrile was fed periodically into the shaking flasks containing Nocardia sp.RS cells and the culture medium.Acrylamide was accumulated gradually along with the hydration of acrylonitrile and the RS cells were acclimated to the increasing acrylamide.The growth of cells

enzymatic hydration of acrylonitrile and the screening of acrylamide-tolerance cells were coupled in the same process.The survival rate and nitrile hydratase activity of cells in the process were investigated.The acrylamide-tolerance of the RS-1 strain achieved in that process was improved significantly compared with the RS strain.The accumulation of acrylamide catalyzed by RS-1 could reach 587 g8226;L-1

which is 30.6% higher than that of RS strain in shaking flasks.And a high acrylamide concentration of 535 g8226;L-1 was also achieved in a bioreactor catalyzed by the strain RS-1.The concentration of acrylamide in the bioreactor was high enough to crystallize directly in 2℃.Based on the high accumulation of acrylamide

an improved process of hydration and crystallization was designed.By applying the improved process

the energy consumption in concentration can be reduced by 32.8% compared with the present process.