When they hit a jack pot. They’d document the mutations, throw the engineered strain out and start blasting them with UV. Afterwards you just scan for the same mutations and voila, now it’s classical strain enhancement!

Instead of starting with a fresh gene pool and blasting it with UV and praying that they get the same jackpot mutations, why didn't they start with an entire population with that desirable jackpot mutation and those blast cells with UV and then select for the ones that survived?