Investigation of Silphium perfoliatum as Feedstock for a Liquid Hot Water–Based Biorefinery Process Towards 2,3-Butanediol

The aim of the present study was to generate a consistent data set for biorefinery intermediates from novel energy crop Silphium perfoliatum compared with Fagus sylvatica, including process streams from liquid hot water pretreatment, enzymatic hydrolysis, and fermentation with Bacillus licheniformis. The consistency of the data set was further supported by the application of a consistent analytical method based on high performance anion exchange chromatography with pulsed amperometric detection and validated for process intermediates, which renders the technique a versatile analytical tool also for alcoholic compounds. For the first time, Silphium perfoliatum was used for liquid hot water pretreatment which resulted in a maximal absolute glucose recovery after enzymatic hydrolysis for feedstock pretreated with 200 °C, 20 min, 20% solid loading. Under these conditions, 68% glucose were recovered for Silphium perfoliatum and 62% for Fagus sylvatica. Further, enzymatic hydrolyzates of both feedstocks were successfully used as single carbon sources for 2,3-butanediol fermentation with Bacillus licheniformis resulting in a 2,3-butanediol yield of 39% and 31% of the theoretical yield for Silphium perfoliatum and Fagus sylvatica, respectively. Thus, the technical suitability of Silphium perfoliatum as feedstock for a liquid hot water–based biorefinery process was comprehensively demonstrated and successfully bore the comparison with Fagus sylvatica.