Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan; Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan. Electronic address: [Email]
Microalgal and lignocellulosic biomass is the most sumptuous renewable bioresource raw material existing on earth. Recently, the bioconversion of biomass into biofuels have received significant attention replacing fossil fuels. Pretreatment of biomass is a critical process in the conversion due to the nature and structure of the biomass cell wall that is complex. Although green technologies for biofuel production are advancing, the productivity and yield from these techniques are low. Over the past years, various pretreatment techniques have been developed and successfully employed to improve the technology. This paper presents an in-depth review of the recent advancement of pretreatment methods focusing on microalgal and lignocellulosic biomass. The technological approaches involving physical, chemical, biological and other latest pretreatment methods are reviewed.