Bio-chemicals from lignocellulose feedstock: sustainability, LCA and the green conundrum†
This article discusses the environmental sustainability of bio-based or green chemicals and highlights various factors determining their “level of greenness”. Life cycle assessment was introduced as a system-wide approach that considers all processes from the extraction of natural resources to various bio-conversion steps that lead to the final product. Three bio-chemicals were selected in the investigation: methanol, formic acid, and acetone. The results suggest that the environmental benefits anticipated from renewable resources to produce green chemicals should be reviewed on a case by case basis. Sensitivity analysis was carried out to demonstrate that a 10% increase in biomass output and its availability (per unit land area) results in more CO2 savings than a 10% increased yield in the bio-conversion methods. More importantly, land use change may have a dramatic influence on the total CO2 emissions for lignocellulose utilization.