Method for preparing an aqueous acrylamide solution having a low acrylic acid concentration

A method for preparing an aqueous acrylamide solution, the method comprising:

• (a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion;
• (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor;
• and
• (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more until an acrylamide content reaches at least 20 w/w %, relative to the total weight of the composition in the reactor.

A method for reducing an acrylic acid concentration of an aqueous acrylamide solution prepared by converting acrylonitrile to acrylamide using a biocatalyst, the method comprising:

• (a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion;
• (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor;
• and
• (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor.

A method for preparing an aqueous acrylamide solution, comprising:

• (a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion;
• (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor;
• (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor;
• and
• (d) obtaining a composition at the end of the bioconversion, which has an acrylic acid concentration of 1500 ppm or less, relative to the total weight of the composition at the end of the bioconversion.