Continuous alkaline pretreatment of miscanthus using single screw reactor

The Miscanthus sacchariflorus strain Goedae-Uksae 1has recently developed as an energy crop, satisfying high productivity, suitability for marginal land quality, lower nutrient requirement…etc. For bioethanol production from Goedae-Uksae 1 pretreatment by which biomass can be hydrolyzed to yield fermentable sugars would be inevitable. Thus, continuous pretreatment system using single screw reactor was developed for potential of industrial application. In comparison to batch mode, continuous pretreatment has many advantages, such as less intensive labors, no solid loss, eases of industrial adaptation and scale up. Effectiveness of the conventional alkaline pretreatment was used as benchmark for the directions of development of continuous pretreatment using single screw for Goedae-Uksae 1. Operating parameters were 3mm of particle size, 22% of moisture content, 140^oC of barrel temperature, 8 mins of residence time, and 15.5g/min and 125.5ml/min of biomass and NaOH loading, respectively. NaOH concentration and enzyme dosage was minimized for saccharification up to 0.5M and 10 FPU g/cellulase, respectively. Consequently, 90.8 ± 0.49 % of glucose yield was achieved at 50 ^oC for 72 hours. The findings from SEM analysis of pretreated samples helped to understand correlation with NaOH concentrations, structural changes, and thereby glucose yield. Furthermore, process wastes (liquid fraction) were recycled for the pretreatment buffer until recycling threshold. Finally, overall mass balances were analyzed following the sequential steps for bioethanol production.