The integrated panel of microbial screens and standard screening methodologies were adopted as previously described [ 14].
More stable BVMOs can be potentially obtained by rigorous protein engineering work, and new enzyme discovery by means of conventional microbial screening or from metagenome libraries and genome sequences.
However, the establishment of MRLs has made us reconsider the original microbial screening methods, such as the EU4pt and one-plate B. subtilis assays, employed in the pre-MRL era, as it should be concluded that for many residues these tests are insufficiently sensitive [ 12, 18, 19].
> Two main dilemmas emerge when considering the validation of the detection capability of a broad-spectrum microbial screening method; the type of sample (matrix) and the number of compounds that should be assessed.
There are probably over a 1,000 amateur biologists worldwide with interests in DNA sequencing, microbial screening, environmental monitoring, or applications for health care and energy [ 6].
Using a growth-based, microbial screening system will dramatically accelerate the cycle of inhibitor discovery and characterization.
For all these residues E. coli ATCC 128 appeared to be superiorly sensitive and this organism was recommended for supplementing the existing microbial screening tests.
However, most current microbial screening tests have been initially developed to detect β-lactams in cow's milk.
Consequently, during the last decade this has led to the development of improved microbial screening methods.
So far only a few microbial screening methods claim to have been validated "according to 2002/657/EC" [ 36, 37, 51, 59].
