A biotechnological approach to upgrade wheat straw into high-performance binderless boards

Abstract

Wheat straw represents a highly promising source for the production of bio-based materials due to its fibrous composition, naturally optimized structure, and high availability as an agricultural by-product. The present study reports the conversion of wheat straw into high-performing fibreboards without the use of bonding agents. In a first step, straw was converted into fibres using a mild semi chemical pulping process. Subsequently, microbial aqueous retting of the fibres was performed for different periods. The fibres obtained were characterized and the microorganisms involved in the retting process were isolated and sequenced. Quantification of xylanase activity indicated substantial enzymatic hydrolysis of hemicellulose. This biotreatment improved both the drainability of the straw fibres and the mechanical properties of hot-pressed binderless fibreboards. Characterization of mechanical and physical properties revealed impressive flexural strengths of 64 MPa, flexural moduli of 6.8 GPa and internal bond of 1.1 MPa after 8 days of bio treatment. The results exceeded the standard requirements for hardboards and demonstrate the possibility of enhancing the performance of straw based binderless boards with natural biotreatment.