In most of the courses at PSG College of arts and science, you need to score above 785 upon 800. (All four main subjects together). For BSc Biotechnology or Microbiology, 600 is the least score for admission. 

For other details please check the link given below

https://www.careers360.com/colleges/psg-college-of-arts-and-science-coimbatore/bsc-biotechnology-self-finance-course