If you plan to go for Chem or Microbio in both of the cases you will need to do PhD because of the job prospects and the nature of the studies. In your case its better to go for non Masters PhD but in a good lab. Why I am saying good lab because you can spend years doing research but you may not have any good results I mean publication. In other words if you are a hard working student then choose also a hard working PhD or Master's supervisor. There is not enough money in this field. Even after PhD you will not be able to make more than 40K in a year (i.e. during your Post Doc). But the objective is to get green card from Post Doc and compete with Americans in a good biotech lab/pharmaceuticals company in future.