Characterization of Mechanically Pretreated Wheat Straw for Biogas Production

Abstract

Biogas production from wheat straw is one strategy of converting biomass to bioenergy, but pretreatment of the lignocellulosic material is necessary in order to render the substrate biodegradable. In this study, four different mechanical pretreatments of wheat straw were investigated: roll milling, extrusion, pelletization, and hammer milling. The effects of the pretreatments on anaerobic digestion (AD) at 37°C and on enzymatic hydrolysis (EH) with Cellic CTec2 at 50°C were analyzed in terms of biochemical methane potential (BMP), maximum daily methane production (DMPmax), and EH yield as amount of released glucan/initial glucan content. Roll milling generated the highest BMP of 287 NmL CH 4 gVS −1 , an increase of 21% compared with untreated wheat straw. Extrusion provided the highest methane production rate (52 NmL CH 4 gVS −1 day −1), the lowest floating capacity, and a high bulk density. It was further concluded that a linear relationship exists between the DMPmax and the EH yield (R 2 = 0.768) which for roll-milled size fractioned wheat straw was even stronger (R 2 = 0.900) but weaker for mechanically pretreated non-size fractioned straw (R 2 = 0.625). Specific surface analysis and EH of 0.25-1-mm particles revealed that mechanical pretreatment most likely affect other physiochemical properties in wheat straw, such as the crystallinity or melting of the outer wax layer, which in turn affects AD and EH processes differently.

Influence of lignin level of raw material on anaerobic digestion process in reorganization and performance of microbial community

“…Table 1 shows the comparative assessment of the biogas efficiencies which indicated that biogas potential of RS, WS, SCL, and CCW without any preprocessing was lower than that observed in the current study. However, the trend for biogas yield reported by these researchers supported the observations in the present study with reference to the biogas production efficiency being affected by lignin content (Elsayed et al 2018;Mokobia et al 2012;Victorin et al 2020;Zhang et al 2018). Increase in biogas and methane yield was achieved by the authors when the above substrates were preprocessed by subjecting to pretreatment with chemicals, co-digested with other substrates, or when operational parameters were optimized.…”

Physicochemical Characterisation and the Prospects of Biofuel Production from Rubberwood Sawdust and Sewage Sludge

“…Normally, the heat is more rapidly and efficiently transferred from one medium to the other in the end product. Therefore, biomass with larger particle sizes will affect the cost of preparation and feeding as well as storage and transportation [28,34].…”

A Review of Pretreatment Methods to Improve Agri-Food Waste Bioconversion by Black Soldier Fly Larvae

“…Reduced substrate particle size has been shown to positively correlate with biogas or methane yield (Victorin et al, 2020), in addition to increasing cellulose degradation (Sharma et al, 1988). Mechanical pretreatments, such as grinding, extrusion, and mechanical disintegration, have already been applied in fullscale for animal manure, municipal solid waste, and agricultural crops and residues (Carrère et al, 2016).…”