B.Tech in Biotechnology in Delhi
Since you have not specified, I am assuming you have not yet decided your career goals. Microbiology and Biotechnology are related fields or sister disciplines with immense research and industrial potential.
Delhi University is a top university and has a certain repute attached to it. It has good research projects and excellent faculty. Most importantly I believe there is a huge contribution of DU cultural in shaping your life and ambitions. The interaction with professors and peers will certainly add value to your choice. B. Sc microbiology would be a good option if you want to go for PhD and research oriented teaching in the fields of immunology, fermentation, virology, metabolism, infectious diseases, biochemistry and pathology.
On the other hand, before joining a private college you need to make sure of two things. Does the college have any good research projects in store for students and whether the faculty are interactive?
Biotechnology from a private college needs to be complemented with a higher degree from a more reputed Institute. But if you are willing to venture into interdisciplinary and Technology based subjects, B. Tech would be a better option. Some options are Environmental and Chemical Engineering, Bio medical, Pharmaceutical industry, Clinical research, Recombinant DNA Technology, Genetic Engineering, Nanotechnology, Biosensors etc. Industrial exposure is better available in Biotechnology (my opinion).
Make sure you are aware of the infrastructure that the private college offers. Talk to some alumni and see what they are doing.
In the end, it ultimately depends on your passion and hard work. Your college degree is just a stepping stone into your career.