Efficient fractionation of corn stover by bisulfite pretreatment for the production of bioethanol and high value products

Abstract

Fractionation of corn stover (CS) was carried out by bisulfite pretreatment in order to improve the production of bioethanol and high-value chemicals. Firstly, the optimum bisulfite pretreatment conditions of CS (170 C, 30 min, 7% NaHSO3, 1% H2SO4) were identified. Next, a biorefinery process of bisulfite pretreatment for CS was proposed. CS was separated into solid and liquor components using such pretreatment. The solid components were employed for bioethanol production by quasi-simultaneous saccharification and fermentation (Q-SSF). The bisulfite liquor was fractionated into hemicellulosic sugars and lignin by different types of resins. It was shown that CS components could be effectively fractionated through bisulfite pretreatment in combination with resin separation to produce bioethanol, hemicellulosic sugars, and lignosulfonate.

Changes of the structures and properties of corn stover during acid sulfite pretreatment for improved enzymatic hydrolysis

“…The CS was pretreated with 7% sodium bisulfite and 1% sulfuric acid at 170 °C for 30 min as described in a previous publication (Tan et al 2019). Table 1 lists the chemical compositions of the CS before and after the acid sulfite pretreatment, as well as the enzymatic conversion rates of glucan and xylan in the untreated and pretreated CS.…”

“…Hemicelluloses can be partially degraded or dissolved under acidic conditions. The sulfite, bisulfite, and sulfur dioxide can attack the Cα or Cγ position of lignin (i.e., sulfonation reactions), which can increase the hydrophilicity of the lignin, which promotes its dissolution (Tan et al 2016;Liu et al 2018;Ren et al 2018;Tan et al 2019). In the present study, the acid sulfite pretreatment caused a 75.08% loss of xylan and a 33.98% loss of lignin, which suggested that both of them were degraded or dissolved to some extent during the process.…”

“…1002 for bioethanol production, which can be roughly classified into chemical, physical, biological, physico-chemical, and combined pretreatments (Kumari and Singh 2018). Among these pretreatment techniques, acid sulfite pretreatment has been reported as one of the most efficient processes (Tan et al 2016(Tan et al , 2019Xing et al 2016).…”

“…Previous research work (Tan et al 2019) demonstrated that acid sulfite pretreatment is an effective and practical method to improve enzymatic hydrolysis of corn stover (CS) for the production of bioethanol with higher conversion rates of cellulose and higher yields of ethanol. However, the possible mechanisms of acid sulfite pretreatment have been rarely discussed.…”

Integration of banana crop residues as biomass feedstock into conventional production of first‐generation fuel ethanol from sugarcane: a simulation‐based case study

“…11 In this context, not only in Brazil but worldwide, several residues are being investigated in order to meet the growing demand for second-generation ethanol. 12 A successful example was work by Reina et al 13 in obtaining lignocellulosic ethanol from Eucalyptus dunnii bark. Using an innovative ionic liquid pretreatment process, the authors reached 70% of ethanol yield, a result fourfold higher than the one obtained using the bark without pretreatment.…”