I’d say YES, do this. We do not know the full scale effects and also how these bacteria would mutate, but if we can use micro-organisms that would generate enough oxygen for us to live and would also generate organic materials that would help plants grow, then why not?
Better to have a bacteria planet than a dead planet. As long as we can also get some plants in there and bring oxygen in the air, that should be a good starting step.
In any case, colonization of Mars is hard because:
– Mars does not have a magnetic field – you are at the mercy of radiation form sun and beyond
– temperatures vary greatly and only on Ecuator you get 20 degrees Celsius
– air pressure is very low
– the air contains mostly carbon dioxide and no trace of Oxygen
– gravity is lower in there
– there is almost no liquid water
– the soil does not have enough nutrients for plants to grow in there
So, colonization of Mars is a tricky thing to do and it may take us hundreds of years to perfect it. I’d like to travel back and forth to Mars some day 😀