Maths Spl

Government colleges offers B.Tech in biotechnology with PCMB but some private universities offer B.Tech in biotechnology without maths too.

Yes, you can get admission in BBA without maths. For direct admission, you need to check with respective college.
Check the below link for colleges-
https://www.shiksha.com/bba/colleges/bba-colleges-kolkata

That entirely depends upon your stream.

Most of the colleges (80%) demand maths as a compulsory subject in class 12th for BCA, but there few colleges around 20% which do not demand maths.

In my point of view, no course is the best on their own, it is the person who studies a course make it best or special.
For bio-maths students:
1) Actuaries
2) bio technology
3) naval/ marine engineering (though you don't want, but in engineering it's a emerging field)
4) naval officer
5) military off

You can go for engineering or you can go for Bachelors in maths. After that, you can go for Masters in field of maths. If you are going for engineering, than after graduation you can go for MS in research oriented fields from US university.