A Review on the Over-liming Detoxification of Lignocellulosic Biomass Prehydrolysate for Bioethanol Production

Abstract

There is an increasing interest in utilizing biomass for biofuel production to mitigate the negative environmental impact caused by fossil fuels. The production of ethanol from lignocellulosic biomass necessitates a pre-treatment process to break down the biomass into fermentable sugars. However, the use of high temperatures and chemical concentrations during pre-treatment leads to the formation of inhibitors, adversely impacting ethanol production yields. Detoxification, the process of removing inhibitors by physical adsorption or by converting them into less harmful compounds, is crucial in preventing inhibition during fermentation. Over-liming detoxification is one of the most employed methods for ethanol production due to its high efficiency, easy operation, and low cost. In addition to the types of alkali used, factors like pH value, temperature, and incubation time also play a crucial role in its effectiveness. Therefore, determining optimal detoxification conditions and selecting suitable alkalis are essential to the successful removal of inhibitors from biomass hydrolysate, ultimately enhancing ethanol production. Suitable microorganisms used during fermentation also have a substantial impact on ethanol production. This review paper summarizes the effect of the alkali detoxification method on the ethanol fermentation of lignocellulosic biomass. The limitations and problems of over-liming detoxification and potential methods that could enhance the over-liming are also discussed.

Graphic Abstract