Development and optimization of hemicellulose extraction bioprocess from poppy (Papaver somniferum L.) stalks assisted by instant controlled pressure drop (DIC) pretreatment

Abstract

Global efforts are being made to replace petroleum-based products with renewable biomass-based products through sustainable processes. Currently, hemicelluloses are of great interest in the framework of the biorefinery approach. This work is aimed to develop a hemicellulose extraction process by combining instant controlled pressure drop (DIC) and alkaline extraction methods and to optimize the process conditions. Opium poppy (Papaver somniferum L.) waste stalks are selected as the model lignocellulosic biomass. Response surface methodology (RSM) was used to determine the effects of DIC process variables with a significant influence on hemicellulose yield including; saturated steam pressure (2-5 bar), processing time (60-540 s) and moisture content (7-85%). Alkaline extraction process conditions covering alkaline (KOH) concentration (5-25%), extraction time (1-7 h) and precipitant volume (25-125 ml) were optimized to maximize the extraction yield and the sustainability of the process. Optimum process conditions were determined as 5 bar saturated steam pressure, 540 s processing time, 7% moisture content for DIC and 22.17% KOH, 7 h extraction time, 53.28 ml precipitant volume for alkaline extraction. Under the verified optimum conditions, 26.23 +/- 0.04% hemicellulose extraction yield was reached. As a result, hemicellulose yield was increased by 49.7% with the co-current saving in the amount of KOH and the precipitant solution used, and shortening of the processing time. The destructive effect of DIC on the stalks was demonstrated by SEM analysis.