Colleges in Amravati

Candidate must have passed 10+2 or equivalent examination from a recognized school/board.

The fee structure at SGBAU for Bachelor of Social Work (B.S.W.) is 20,000 to 60,000 Approx.

If you want to go for M.Sc in microbiology, you need to have a bachelor's degree in any scientific discipline. But it's not necessary to have a particular degree.
As you have mentioned that you have a degree in microbiology that means you don't need to worry. You can easily get admission in M.Sc microbiology.

The fee structure at SGBAU for Ph.D. in Botany is 31,100.

Yes, it is available at SGBAU.

GCOEA Amravati fee structure for B.Tech. Civil Engineering is INR 84,290 Annually.

This course is of 3 long years with the fee of IN 42,594. It is one of the reputed colleges, the detailed information is given down here, open the link
https://educationiconnect.com/sgbau-amravati-university-fee-structure/

Yes absolutely you are eligible.