Recycling cassava stem to bioethanol by inoculating a novel xylose–glucose fermenting yeast at high initial concentration

Converting cassava stem (CS) to bioethanol instead of burning or allowing them to decay on open fields can contribute to efforts on reducing CO2 emission and fossil fuel use. New xylose-glucose fermenting yeast Blastobotrys adeninivorans XE1 was inoculated on non-detoxified acid hydrolysate of CS to produce ethanol. Experimentally, at low furfural concentrations (0.24 ± 0.05 g/L) in non-detoxified acid hydrolysate of 100 g CS/L, B adeninivorans XE1 (~107 CFU/mL initial concentration) degraded furfural fast and then converted both glucose and xylose to ethanol. However, at higher furfural concentration (0.51 ± 0.11 g/L) in non-detoxified acid hydrolysate of 150 g CS/L, B adeninivorans XE1 (around 107 CFU/mL) was unable to degrade all furfural, ethanol production by B adeninivorans XE1 was reduced. Increasing initial concentration of B adeninivorans XE1 to around 108 CFU/mL surpassed furfural inhibition and produced 17.4 ± 0.8 g/L ethanol on medium of non-detoxified acid hydrolysate of 150 g CS/L after 60 hr.

https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.13286