Rapid Optimization of Typha Grass Organosolv Pretreatments Using Parallel Microwave Reactors for Ethanol Production

A comparative study of organosolv process was performed at laboratory scale using traditional stainless steel batch reactor with parallel microwave (MW) reactors. Ethanol (with sulfuric or soda catalyst), formic acid, and performic acid organosolv processes were first optimized for the pretreatment of Typha capensis using MW reactors. The best conditions based on mass balance and Klason lignin content were reassessed using a traditional pressure steel reactor. The enzymatic hydrolysability of soda process revealed better results (reducing sugar yields = 77-87%) as compared to the sulfuric acid process (reducing sugar yields = 57-66%). Substantially higher delignification and better enzyme hydrolysability were observed for the formic acid process with hydrogen peroxide catalyst. This process produced a pulp with very low residual lignin (<3%) and a high cellulose-to-glucose conversions (>85%). It can be concluded from this study that parallel microwave technology could be used for rapid optimization of biomass pretreatment to narrow down the range of process parameters studied before a final optimization using a classical pressure reactor.