Cell wall hemicellulose for sustainable industrial utilization

Despite a steady decline in fossil resources in past few decades, demand for petroleum-based chemicals and polymers has increased sharply. As the dead end of the petroleum industry has begun to emerge, mankind must immediately seek for alternative energy and other biopolymer resources. Hemicellulose being an abundant component of lignocellulosic biomass, may serve as a promising alternative for replacing dwindling fossil resources with many important fuels and biopolymers such as furfural, HMF, etc. Utilization of hemicellulose in the present review is divided into two sections; in the first section, products manufactured in the industry by direct modification of hemicellulose either by attaching different functional groups or other polymers are discussed, while in the second section, products or polymers produced by hemicellulose degradation are discussed along with their use. Modifying hemicellulose with different functional groups enhances their reactivity and has extensive utilization in medicine, food, packaging, and many other industries. Likewise, downstream compounds derived from hemicellulose degradation can be used as fuel additives, plastics, etc. Xylose is the main sugar derived from xylan and is utilized in almost all products discussed in this review. Metabolic engineering assisted conversion of xylose is booming the hemicellulose utilization in the biobased industry. Further improvement in microbes and synthesis pathways, coupled with the advent of new technologies would lead to extensive use of hemicellulose in biofuel and biopolymer industries. The present review paper presents the current research about hemicellulose utilization and thus encourages in-depth studies in this area.