Alkali pretreatment 1 Alkaline pretreatment Biofuels 1 Biomass 1 Biomass ratio 1 Butanol 1 Butenes 1 Clostridium 1 Clostridium beijerinckii 1 Efficiency 1 Enzymatic hydrolysis 1 Fermentation 1 Mass balance 1 NaOH pretreatment 1 Optimisations 1 Pre-treatments 1 Rice straw 1 Rice straws 1 Sodium hydroxide 1 Solid loading 1 alkalinity 1 biofuel 1 biomass 1 chemical mass balance 1 concentration (composition) 1 fermentation 1 fungus 1 glucose 1 hydrolysis 1 optimization 1