Renewable Rubber and Jet Fuel from Biomass: Evaluation of Greenhouse Gas Emissions and Land Use Trade-offs in Energy and Material Markets

Biomass holds great promise for producing fuels, chemicals, and polymeric materials to address climate change and energy security. Polyisoprene, the raw material used to produce rubber, can be produced from rubber trees and synthesized from the monomer that is derived from both petrochemical feedstock and fermentable sugars in biomass. We explore select life cycle environmental impacts of an alternative pathway for producing polyisoprene from corn stover and forest residue along with dimethyl cyclooctadiene, a high density jet fuel blend. Following feedstock pretreatment and hydrolysis, the sugars generated are fermented to methyl butenol (MBE) and then dehydrated to isoprene, which is further polymerized to polyisoprene. Within the same dehydration reactor, MBE undergoes catalytic conversion to dimethyl cyclooctadiene. We use life cycle assessment to evaluate the greenhouse gas (GHG) emissions and land requirements for producing polyisoprene produced from forest residue and corn stover and compare these to polyisoprene produced from petroleum and rubber trees. Both corn stover and forest residue-based polyisoprenes have negative global warming potential (GWP) between −5.7 to −1.3 kg CO2e/kg polyisoprene, even while considering sources of uncertainty. Moreover, polyisoprene from rubber tree plantations in Southeast Asia has the most significant land use intensity compared to other feedstocks.