Preparation of crystal flakes of p-coumaric and ferulic acids from Erianthus arundinaceus culms and leaves as a side process of cellulosic-ethanol production

We developed a simple process for the preparation of crystal flakes of p-coumaric and ferulic acids from an extract obtained after the alkali pretreatment of Erianthus arundinaceus culms and leaves for the calcium-capturing-by-carbonation (CaCCO) process for cellulosic-ethanol production. These phenolic acids were moderately extracted by calcium hydroxide and purified by adsorption to the synthetic adsorbent SP700 with subsequent elution by 60% (v/v) ethanol solution. After concentrating the eluate by evaporation and allowing the resultant murky solution to settle, yellow crystal flakes mainly consisting of p-coumaric acid (82.0% of the total weight) and ferulic acid (7.4 % of the total weight) were obtained, corresponding to recoveries of 46.3 % and 13.1 %, respectively. Thus, we demonstrated a new side process for phenolic acid recovery by simple purification steps. The integration of this side process into the main cellulosic-ethanol production stream could not only save eluent (ethanol) but also enable the ethanol in the eluate to be reused with the aid of a distillation facility in the main stream, thereby strengthening the ability of the bio-refinery industry to produce cost-competitive valuables.