AMMONIA-BASED PRETREATMENT FOR LIGNOCELLULOSIC BIOMASS CONVERSION – AN OVERVIEW

Abstract

Lignocellulosic biomass is generically known to describe a plant-based biomass, typically agricultural residues that forming a complex structure of cellulose, hemicellulose and lignin. In Malaysia, there is about 168 million tons of lignocellulosic biomass been produced locally and provide an opportunity for industries to make a breakthrough in biomass utilization. Currently, several pretreatment technologies have been progressively developed, preparing it for efficient downstream utilization such as acid or enzymatic hydrolysis. Ammoniabased pretreatment has become as one of the most attainable chemical options due to its high potential in the post- pretreatment effect and future commercial utilization. The most promising feature of this pretreatment owes to the ability of ammonia to be selective and effective in removing the lignin and allowing the carbohydrates to be easily digested in bioconversion. This paper intends to provide an overview on the biomass conversion using the ammonia-based pretreatment focusing on the fundamental concept on the lignocellulosic biomass and ammonia itself, aspect of the ammonia-based pretreatment, the chemical reaction of carbohydrates, the process from the aspect of chemical and physical changes in biomass and hydrolysis performance. This review also discusses the ammonia handling in the operation and safety precautions requirement during the development of EFB pretreatment process.