b'There is hopefully a middle ground, where the plant pro-duces enough saponins to resist most fungal pathogens, while genetic engineering can make the biofuel-producing yeast more tolerant to those saponins, he says.The Hidden Chemistry of a Hotter FutureSwitchgrass has long been a darling of the biofuel worlda hardy perennial that grows on marginal land and generates six times more energy than it takes to grow. But climate extremes like the 2012 drought in Wisconsin revealed just how much chemistry can change when plants are stressed.GLBRC researchers compared switchgrass harvested in both drought and non-drought years. The difference in fermentation was striking. When broken down by conventional pretreatment and hydrolysis methods, the drought-year biomass yielded sig-nificantly less ethanol.The solution isnt to reject drought-grown biomass outright, but to adjust how its processed.The study shows that pretreating the grass with ammo-nia and raising the pH of the resulting hydrolysate can restore feedstock producerS mayfermentation efficiency, even with saponins present. Enzymatic hydrolysis and microbial performance both improve when acidity be focuSed on using theis moderated.This suggests processing facilities may have some control cultivar with the highestover droughts impactbut it also means feedstock composi-yield per hectare, but thattion needs to be treated as a dynamic variable, not a static input.approach may not equate toMore Than Just Yield Per HectareSatos research may nudge breeders and seed companies to the highest biofuel yield.reconsider how they evaluate switchgrass and similar bioenergy crops. Yield per acre remains the standard for feedstock selec- trey sato tion, but that might not reflect the total fuel potential per ton of biomass.Feedstock producers may be focused on using the cultivar with the highest yield per hectare, but that approach may not equate to the highest biofuel yield, Sato says.One answer could be to engineer switchgrass and otherFermentation efficiency data could help in deciding what bioenergy crops to make fewer saponins, he says. varietals a grower would want to select.However, saponins are important plant defense molecules.Still, its not simple. Between the biological variability of so, reduction in saponin production will likely affect the plantsswitchgrass and the wide range of deconstruction methodsfitness in the field and potentially reduce biomass yield. acids, bases, solventstracking fermentation metrics across Sato sees hope in the middle ground. Breeders might notevery scenario is daunting.need to choose between plant health and fermentation potential.It would be challenging to generate a fermentation dataset, The yeast itself could evolve to do the heavy lifting. he says.46/ SEEDWORLD.COMOCTOBER 2025'