A polymerase chain reaction (PCR) protocol was developed for the specific detection of genes coding nitrile hydratase (NHase). Primer design was based on the highly conserved sequences found in the coding region of the alpha-subunit gene corresponding to the metal-binding site. Purified genomic DNA from bacterial strains or directly from soil can serve as the target for the PCR, thus affording a simple and rapid method for screening NHase genes. The primer pairs, NHCo1/NHCo2 and NHFe1/NHFe2 yield PCR products corresponding to a partial coding sequence of cobalt and iron NHase genes, respectively. Using the PCR method, both types of iron- and cobalt-NHase-encoding genes were detected in DNA from pure cultures and soil samples. Furthermore consensus primers allowed rapid cloning and expression of novel NHases in Escherichia coli.

Rhodococcus pyridinovorans MW3 was isolated from an arable land of manioc from the Congo for its ability to transform acrylonitrile to acrylamide. This strain contains a cobalt nitrile hydratase (NHase) showing high sequence homology with NHases so far described. The specific NHase activity was 97 U mg(-1) dry wt. NHase production by R. pyridinovorans MW3 was urea and Co-dependent. The NHase was active for acrylamide up to 60% (w/v) indicating its potential for acrylamide production.

Extracellular peroxidases play an important role in the degradation of chlorophenols by Phanerochaete chrysosporium. Depending on the moment of 3,4-dichlorophenol addition, the production of lignin peroxidase and manganese peroxidase in C-limited agitated cultures was affected in opposite ways. In cultures that received 3,4-dichlorophenol at the time of inoculation, fungal growth was reduced and peroxidases were not produced, whereas peroxidase activities were stabilized after 3,4-dichlorophenol addition to pregrown cultures. Further investigation revealed that mRNA encoding lignin peroxidase was not produced in cultures started with 3,4-dichlorophenol, suggesting that the onset of secondary metabolism was affected. In addition, the stabilization of lignin peroxidase activity was not the result of an activation of lignin peroxidase gene transcription, as shown by Northern blot experiments, but likely due to the inhibition of peroxidase degradation by extracellular proteases.