ABBS

Yes ABBS is one of the best colleges in South India. You can apply for the course for more detail please contact to the admission department. I have shared college link below:
http://www.acharyabbs.ac.in/

I would suggest you to go with PGDM from ABBS, reason being in terms of experienced faculty, campus life, industrial visit, corporate tie-ups, infrastructure, placement ABBS is better than GIBS.

Both are at their place. There is no such difference when its about MBA but AIMS-MBA department has professors from IIM-B, IIM-A. I guess this is enough for you to understand the quality of education.

ABBS hostel facility and the environment is very good. Occupancy options are single, double and triple. Food quality is also very good. Hostel also provides Wi-Fi facility.

Yes there are private hostels and PG as well. And for college hostel charges are doubt occupancy 90+k and triple occupancy is 85+k. PA.

Yes, Acharya Bangalore b school is good for B.Sc microbiology. After you graduation you can pursue M.Sc in microbiology from ABBS itself.
All the best.

ABBS is approved by UGC, NAAC , AICTE, NBA and IACBE. PGDM programme is affiliated to AICTE and yes it is equivalent to MBA.

ABBS, Bangalore for MBA is really a very good option to pursue placements are more then 90% with average package 4.5 lakhs, 140 companies showed positive response this year. And for fees detail you can contact to admission Department link is below:
http://www.acharyabbs.ac.in/

ABBS and AIMS are two different institutions. ABBS has a certain edge because of infrastructure, experienced faculty, industrial exposure, placements And campus facilities. I would suggest you go with ABBS.
All the best.