Competitor California-based Bolt Threads uses a different approach by not using spiders or silkworms at all and instead uses primarily sugar, water, salts and yeast. “We are still refining our recipe, but that’s the gist of it,” according to Bolt’s website.
I guess instead of sugar, they're experimenting with HFCS:
HFCS has replaced sugar in many processed foods mostly due to the fact that it is cheaper than sugar. It is cheaper than sugar because of taxpayer-funded government subsidies for corn and government tariffs on imports of sugar.