Minify & Concatenate Enqueued Scripts & Styles.
Fatal error: Allowed memory size...
You have probably created an infinite loop when working out the order of depencies.
Example: Files 1, 2 and 3 are enqueued. File 1 is a dependency of 2, which is a dependency of 3. If only scripts 1 and 3 are minified and concatenated into 1 file, it will fail. This is because the processed file is now a dependency of file 2, but file 2 is also a dependency of it.
Solution: You must either process all files together, or process 1 and 3 in separately.