Yeah, I’ve seen a few of these startups over the years. My gut tells me it’s an interesting gamble - it’s a matter of timing really. I have no doubt that the frequency of launches will increase enough that the fuel will become an environmental concern, but we’re not there yet.
I’d want to see a EO launcher describe their desire to purchase a biofuel first before I’d back a biofuel launch startup. It would be a long shot to take a “build it and they will come” approach since the chemistry of the fuel is so closely tied to the design and performance of the rocket engines which are the pivotal point of differentiation for a launch provider today. It’s not like an ICE engine of a car where it might be able to be tuned for E10.
Like a lot of space startups out there, I’ll be disappointed if this is a tech-first approach as I suspect it is. Start with a problem that someone will pay for, and then find out what tech can be produced to solve it.