B.Sc

Choose what you love. Also look at the curriculum and the university. Pursue career in microbiology only if you get admission in a good and prestigious institute. Zoology is a core subject and hence offers a wide range of career opportunities whereas microbiology is an specific course. Although there are bright opportunities in microbiology but look for some good institute.

JIS University, SRM University, Tamil Nadu Agricultural University, Mahatma Phule Krishi Vidyapeeth, Bisra Agricultural University, Khalsa College etc.

Amity University, Banasthali Vidyapith, University of Rajasthan, Jaipur National University etc.

Mount Carmel College, Kristu Jayanti College, Reva University, Dayananda Sagar University etc.

Refer the following:
Amity University, Sumandeep Vidyapeeth, Jiwaji University, Madras University etc.

Refer the following:
JSS Medical college, VIMS Bangalore, Amrita Vishwa Vidyapeetham, Yenepoya Medical College

https://www.shiksha.com/nursing/colleges/b-sc-colleges-Kerala
Check out the colleges here.