[Aerroon]

I thought the same thing initially, but I'm not as convinced after looking a bit more into it. Ie I think it's a possible risk.

>as there are no natural mirror aminoacids. Normal bacteria will quickly evolve to consume mirror aminoacids.

There are and they already have:

>D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free.

https://pubmed.ncbi.nlm.nih.gov/24647559/

On the one hand, this does indicate that the "mirror bacteria" might not starve immediately, but on the other hand it shows that "non-mirror bacteria" would already be there in large numbers.

[kragen]

It would hardly be beyond plausibility for an ingenious researcher to solve the problem of having to feed her mirror bacteria expensive L-glucose by endowing them with an enzyme to enantiomerize cheap and abundant D-glucose. Or, as you implicitly suggest, for the genome she's using to contain such an enzyme already, lurking undetected.