Advice me on doing masters degree in us.

You certainly need GRE/TOEFL and the best way to understand is to write to the university directly to find out. Most of the faculty will be happy to share the information they know!

 

Doing this online is a very bad idea. Biochemistry & microbiology are experimental sciences. Without lab experience your degree will not carry you very far. Getting a job will be very difficult. You will have to invest more time working as an unpaid volunteer to get lab experience. If you have a strong interest in these subjects, it is better to do it with a lab / thesis research option. Then, stay in that lab (even if unpaid) and continue the project while you look for a job. You will increase your lab-experience and they will be happy to have you since you are already trained in that project.
If you have constraints which require that you pursue a degree online, then go for a degree in informatics, after which you can find a position in microbial informatics or other related fields. There are good programs online.

If you are talking about time: With a research option it will take about 2 years or perhaps a bit longer depending on how ambitious your thesis project is.
If you are talking about money: It will cost somewhere between $30K - $36K. It may be cheaper if you are eligible for in-state tuition at a state university.

If you were educated in India, the TOEFL will be mandatory. You may be able to get it waived if you can go for an interview and demonstrate good command of English. The GRE may or may not be required, depending on the university.

Another, more cost effective option is to get a job at a university, preferably in a lab (depending on your previous experience). Then you can use your employee-tuition benefit to get an MS for free. However, I understand that since you asked about online degrees, this may not suit your needs / situation.

Good Luck!

 

Few Universities don't require TOEFL. Check with those universities.