Enhancing Napier Grass Degradation Efficiency through Microwave Pretreatment and Cellulase Enzyme Application

Abstract

Napier grass is a promising energy crop for renewable sugar-based carbon production, where effective pretreatment is essential to enhance its biomaterial value. The objective of this research is to determine the optimal conditions for Napier grass pretreatment and achieve the highest level of efficiency in analyzing the initial lignocellulose content, total dissolved solids, and reducing sugars. The research applies Napier grass from the Pak Chong variation in the province of Phra Nakhon Si Ayutthaya, Thailand. Napier grass was pretreated with 0.5% sulfuric acid (v/v) at 140°C for 60 minutes, yielding a maximum cellulose content of 89.62%. This treatment effectively removed hemicellulose and lignin, with only 5.22% and 0.58% remaining, respectively. When the pretreated Napier grass is subjected to thermal and cellulase enzyme degradation and then treated with a microwave at 700 watts for 15 minutes, the initial total dissolved solids amount is 8.13 g/L, with total sugars and reducing sugars at 7.03 g/L and 91.34 mg/g dry weight, respectively. Adding 20 U of cellulase enzyme for 48 hours significantly enhances the degradation rate, resulting in a total sugar content of 13.95 g/L and reducing sugar content of 165.61 mg/g dry weight of Napier grass. The findings of this research are crucial for advancing biomass energy as a sustainable and environmentally friendly renewable energy source. Methane emissions commonly produced during fermentation can be minimized, thereby lowering the carbon footprint of biofuel production. Enhancing the degradation efficiency of Napier grass increases sugar yield, thereby improving its suitability for bioethanol and biofuel production.