ABSTRACT
Owing to the enhanced worldwide energy demands, rising prices of petroleum-based feedstocks and mounting global warming-based environmental pollution issues, research efforts are now more focused on the development of sustainable green energy, based on some renewable feedstocks. Recently, second generation feedstock, more especially nonfood lignocellulosic biomasses are gaining huge importance as a potential feedstock for sustainable green biofuel production. Being polysaccharides, cellulose and hemicellulose which are part of lignocellulosic material can be easily hydrolyzed
to sugars and then fermented to bioethanol. Although agriculture-based lignocellulosic bioresources in terms of waste are largely available in this world but development of economic, sustainable, and environment friendly bioethanol production process through selecting such feedstock has been still the major challenge persisting in this area. Consolidated bioprocessing (CBP), which integrates enzyme production, saccharification and fermentation, simultaneous saccharification and fermentation (SSF), separate hydrolysis and fermentation (SHF) are the promising strategies for effective ethanol production from such lignocellulosic materials. The application of thermotolerant yeast strains or thermophilic bacteria with thermostable enzymes to the process would overcome the drawback by performing hydrolysis and fermentation at elevated temperature. To overcome all the existing complicacies and problems associated with second-generation biofuel production, process integration of pretreatment processes with saccharification processes or saccharification process with fermentation process or enzyme production. Saccharification processes with fermentation process plays an instrumental role to make the overall process realistic and commercially sustainable. Development of some advanced membrane reactor-based green processes facilitate SSF, SHF, simultaneous saccharification, filtration, and fermentation (SSFF) schemes in more intensified and simplified way.
