Process for producing amides by use of microoganisms

In a process for hydrating a nitrile compound by the action of a microorganism having nitrilase activity to convert the nitrile compound into the corresponding amide compound, in which the microorganism having nitrilase activity is contacted with said nitrile in a reaction vessel under conditions which effect the conversion of said nitrile to the corresponding amide, wherein the microbial cells are present in the hydrating medium in a concentration of at least 0.01% by weight, but wherein the amount of environmental light relative to the microbial cells in the reaction vessel is less than 1.times.10.sup.-2 .mu.E/g.multidot.microbial cells.multidot.second, the improvement which comprises conducting the reaction under the conditions wherein:

• (a) the microorganism having nitrilase activity is positive Gram staining,
• (b) the microbial cells are allowed to accept light energy having a wavelength of about 100 to about 1000 nm in an amount of at least about 1.times.10.sup.-2 .mu.E/g.multidot.microbial cells.multidot.second before termination of the hydration reaction, and
• (c) the hydration reaction is carried out in a reaction vessel which is composed at least partly of a material which does not permit transmission therethrough of light, whereby light energy from the environment of at least 1.times.10.sup.-2 .mu.E/g.multidot.microbial cells .multidot.second is not available in said reaction vessel.