Biotech is a giant field, so it really depends what you want to do. I did my undergrad in CS but spent the past ~4 years working at a molecular diagnostics startup, where I do software engineering/stats/machine learning work. Along the way, I learned a fair deal of biology, the fundamentals of the molecular assays we work with, but more importantly the skills fundamental to science (inquiry, designing experiments, generating new knowledge, skepticism, etc.). Honestly, the biggest transition from CS -> sciences is not the specific biology or understanding of experimental techniques, but rather learning how to think like a scientist. These are skills you probably will not have if you come from a strictly programming background.
If you are really serious about starting a biotech company, you will need to get a PhD in an applied or natural science or work at an immature startup with a team of PhDs thats needs programming help and you can hopefully learn the 'scientific' skills you need along the way. If you restrict the space of companies you want to start to be strictly in the bioinformatics space, then you can probably bypass the PhD route, but you'll need to get a job doing that sort of work at a startup. Job descriptions for those roles should tell you what specific skills you would need for that. Also, I would highly recommend becoming good at stats. Thats fundamental to any path you go down, and can be another way for you to provide immediate value to others.