The effect of atmospheric pressure plasma pretreatment with various gases on the structural characteristics and chemical composition of wheat straw and applications to enzymatic hydrolysis

Abstract

The effects of atmospheric pressure plasma pretreatment (PT) on the enzymatic hydrolysis (EH) of wheat straw were investigated, applying air, N2 and CO2 as the plasma gases onto wet substrate environment for varying durations. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and compositional analyses were all used to characterize changes in the structure and composition of the wheat straw. The composition, structure, and surface of the straw were changed considerably through pretreatment, all of which promoted enzymatic hydrolysis. The optimal conditions (90 s, air plasma) merged advantages both very high biomass/sugars recoveries as well as high conversation yield of glucan and xylan with the overall production of 358.4 and 135.8 mg g−1 respectively following 24 h EH. Considering the feasibility of PT at the optimum with subsequent EH to glucose and xylose production process of wheat straw, PT showed a positive impact on the energy balance of the process with an only input energy of 189.97MJ/t that led to net energy gain of 1297.8 MJ/t of the process. Energy-processing costs of PT and subsequent EH estimated to be $ 0.052 MJ/kg glucose and xylose, demonstrating the significant potential of PT to be scaled to industrial-level in biorefineries.