Improvement of potassium permanganate pretreatment by enzymatic saccharification of rice straw for production of biofuels

Parita Mutrakulcharoen,Atthasit Tawai,Peerapong Pornwongthong,S.T Anne Sahithi,Malinee Sriariyanun,Theerawut Phusantisampan,M Sriariyanun,M.P Gundupalli,Y.S Cheng,W Rodiahwati

doi:10.1051/e3sconf/202130202013

Abstract

Commonly, the agricultural waste, i.e. lignocellulosic biomass is disposed through combustion causing air pollution with production of PM2.5 and PM10 particles. However, it has been found that these biomasses can be used as source for the production of biofuels and other valuable biochemicals. Though deconstruction of lignocellulosic biomass is challenging due to its complex structure. In this study, rice straw (RS) was pretreated using potassium permanganate (KMnO4) to enhance the enzymatic saccharification efficiency. The study was carried out by varying the operational factors in pretreatment, including temperature (30-90°C), time (30-360 min) and concentration of KMnO4 (0.5-3.0, % w/v), respectively, based on Box-Behnken design (BBD). Through multi-regression analysis of the experimental data obtained after pretreatment, the optimum conditions were determined. The optimum conditions for temperature, time and potassium permanganate concentration were 48.09°C, 360 min, and 1.36% w/v, respectively. The saccharifications of pretreatment and untreated rice straw were carried out using Cellic Ctec2. The reducing sugar was determined by using DNS method and the yields of the untreated and pretreated RS were 32.38 and 49.011 mg/mL, respectively. The results showed that the sugar for pretreated RS were 1.51 fold times higher compared to untreated RS. Therefore, this work illustrates the pretreatment efficiency for KMnO4 to enhance the reducing sugar yield during saccharification, which can be used for biofuel and value-added product productions.

Highlights

Lignocellulosic biomass is an inedible organic material source having the potential to be utilized as an alternative source for fossil fuels
The KMnO4 concentration was varied between 1-4%, and the pretreatment time and temperature were set at 40°C for 4 h (Figure 1c)
It was noted that the reducing sugar yield was higher initially (27.04 mg/mL), when the KMnO4 concentration was maintained at 1% w/v

Summary

Introduction

Lignocellulosic biomass is an inedible organic material source having the potential to be utilized as an alternative source for fossil fuels. Common lignocellulosic biomass includes forest residues, agricultural residues and dedicated crops. It has been reported in 2013 that 62 million tons of waste biomass are generated from the agricultural activities of Thailand. Increase in the waste generation is related to the continuous increase in the food demand due to the rapid growth of population. One of the causal agents of these polluted particles was due to the incineration of waste biomass generated after the harvesting seasons. This tradition is being followed worldwide to prepare the soil for harvesting season. Incinerations of agricultural residues increase in the emission of carbon dioxide (CO2), an important of greenhouse gas

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