Potential bioethanol production from Taiwanese chenopods (Chenopodium formosanum)

The potential bioethanol production from an endemic Taiwanese chenopod (Chenopodium formosanum Koidz.) that displays strong productivity and great adeptness was investigated. Both SPROL (sulfite pretreatment to overcome the recalcitrance of lignocellulose) and acid explosion were employed to pretreat harvested Taiwanese chenopod biomass. Escherichia coli KO11 was employed to co-ferment hydrolyzed 5 and 6 carbon sugars. For the SPROL processes, an optimal lignin removal (from 204.6 to 83.8 g/kg oven-dried sample) was achieved when using 12 g of NaHSO3 per 100 g of oven-dried sample at 185 °C for 30 min. The enzymatic hydrolysis of the SPORL-pretreated biomass converts 93.0% and 95.7% of glucose and xylose, respectively. For the acid explosion processes, the optimal lignin removal (145.2 g/kg oven-dried sample) was achieved with 3% H2SO4 at 185 °C for 10 min. The enzymatic hydrolysis process for the acid-exploded biomass converted 94.7% and 74.8% of glucose and xylose, respectively. The final bioethanol conversions by E. coli KO11 were 0.27 and 0.23 L per kg of oven-dried Taiwanese chenopod biomass for the acid-exploded and SPROL-pretreated biomass, respectively. The yields of the Taiwanese chenopod biomass were investigated and found to be 24.3-33.3 tons of dried biomass per ha for three annual harvests.