Pilot-scale fermentation of aqueous-ammonia-soaked switchgrass.

Aqueous-ammonia-steeped switchgrass was subject to simultaneous saccharification and fermentation (SSF) in two pilot-scale bioreactors (50- and 350-L working volume). Switchgrass was pretreated by soaking in ammonium hydroxide (30%) with solid to liquid ratio of 5 L ammonium hydroxide per kilogram dry switchgrass for 5 days in 75-L steeping vessels without agitation at ambient temperatures (15 to 33 degrees C). SSF of the pretreated biomass was carried out using Saccharomyces cerevisiae (D(5)A) at approximately 2% glucan and 77 filter paper units per gram cellulose enzyme loading (Spezyme CP).

Aqueous ammonia soaking of switchgrass followed by simultaneous saccharification and fermentation.

Simultaneous saccharification and fermentation (SSF) of switchgrass was performed following aqueous ammonia pretreatment. Switchgrass was soaked in aqueous ammonium hydroxide (30%) with different liquid-solid ratios (5 and 10 ml/g) for either 5 or 10 days. The pretreatment was carried out at atmospheric conditions without agitation.