Assessing the viability of recovering hydroxycinnamic acids from lignocellulosic biorefinery alkaline pretreatment waste streams.

The hydroxycinnamic acids, p -coumaric acid ( p CA) and ferulic acid (FA), add diversity to the portfolio of products produced by grass-fed lignocellulosic biorefineries. The level of lignin-bound p CA in Zea mays was modified by alteration of PMT expression. The biomass was processed in a lab-scale alkaline-pretreatment biorefinery process and the data was used for a baseline technoeconomic analysis to determine where to direct our future research efforts in coupling plant design to biomass utilization processes. We concluded that future plant engineering efforts should focus on strategies that ramp up predominantly one type of hydroxycinnamate ( p CA or FA) and suppress accumulation of the other. The technoeconomic analysis indicated that target extraction titers of one hydroxycinnamic acid need to be >50 g/kg biomass, at least a five-fold higher than our observed titers for the impure p CA/FA product mixture from wild-type maize. The technical challenge for process engineers is to develop a viable process requiring more than 80% reduction in the isolation costs.