Biofuels firm Gevo says it has developed a catalytic process to make isoprene from low-cost or even waste renewable alcohols. The ability to use cheap feedstocks such as mixed alcohol by-products from ethanol production means the process can create the synthetic rubber raw material at a competitive price, the company claims. Gevo is among a handful of firms that pursued fermentation routes to isoprene. But that route has since been deemed too expensive. Gevo hopes to license the technology to ethanol and chemical producers.