Utilization of Rice Straw into Bioethanol through Biological Pathways

¹ Doctoral Program of Environmental Science, School of Postgraduate Studies, Universitas Diponegoro, Semarang 50241, Central Java, Indonesia
² Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro, Semarang 50275, Central Java, Indonesia
³ Department of Food Technology, Faculty of Animal and Agricultural Sciences, Universitas Diponegoro, Semarang 50275, Central Java, Indonesia

^* Corresponding author: andhikasukma@students.undip.ac.id

Abstract

The increasing burning of fossil fuels and changes in land use and forestry increase the CO₂ in the earth's atmosphere. This condition increases the earth's global temperature, thus causing climate change. In addition, the volume of rice straw waste is very abundant, and the most popular treatment is burning in rice fields. This process also contributes to air pollution and an increase in CO₂ gas. Meanwhile, straw is lignocellulosic biomass containing cellulose and hemicellulose as a source of sugar to be converted into bioethanol. Lignocellulosic biomass conversion consists of three main stages, pretreatment, hydrolysis, and fermentation. The process of converting rice straw into bioethanol has been developed. However, the current obstacle is that the conversion process requires high energy, produces chemical waste, and is not environmentally friendly. A biological approach is preferred so that the rice straw conversion process becomes more sustainable. This paper reviews the pretreatment, hydrolysis, and fermentation processes in biologically converting rice straw into bioethanol. Thus it is expected to be able to respond to existing challenges through a biological and more environmentally friendly approach.