Hydrothermal and enzymatic treatments of pineapple waste for energy production

Abstract

Nowadays, alternative energy from biomass has become more popular globally. Pineapple waste, one of the non-edible biomass sources from agricultural waste, can be used as an alternative source of sugar for ethanol production. However, the production of glucose from cellulose using conventional process would generally be retarded by lignin content. Therefore, the objective of this study is to investigate the effect of the hydrothermal treatment followed by the enzymatic treatment on the cellulose conversion with the presence of different lignin contents and compare the result with conventional method. Also, the physical structures of solid residues from both techniques are analyzed and compared. The results show that the hydrothermal treatment at 185°C followed by the enzymatic treatment can convert pineapple waste to a higher amount of monosaccharide, which is composed of glucose and fructose. Furthermore, the combined treatments can provide up to 23.90 % higher for the glucose yield and 226.7 % higher for the fructose yield than that of the pure enzymatic treatment. Furthermore, the reduction in the lignin content from 20.43 % to 10.88 % by weight can substantially enhance the glucose yield up to 23.90 %. Moreover, the hydrothermal treatment process can decompose the lignin structure between each cellulose strand. Without this treatment, the lignin structure will not be broken down and retard the effectiveness of enzymatic treatment.