Bioethanol production from rice straw residues

Abstract

A rice straw - cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 °C, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L−1.

Natural deep eutectic solvent mediated pretreatment of rice straw: bioanalytical characterization of lignin extract and enzymatic hydrolysis of pretreated biomass residue

“…World annual rice straw production is estimated to be >950 million tons and, currently, most of these were utilized for feeding cattle, and still a large portion of the rice straw biomass is burnt in the agricultural fields without much usage, thus not only causing environmental concerns like air pollution but also adversely affecting the health hazard issues for humans (Liu et al 2011;Binod et al 2010). However, it is estimated that this amount of rice straw can potentially produce approximately 205 billion liters of bioethanol annually, which is the largest amount from a single biomass feedstock (Belal 2013). Like other lignocellulosic residues, the main contents in rice straw are cellulose (32-47 %), hemicellulose (19-27 %), and lignin (5-24 %).…”

Enhanced Bioethanol Production from Industrial Xylose Residue Using Efficient Delignification

“…In a previous study, acid-pretreated rice straw had a lower ethanol production of 10 g/L (Belal 2013). An ethanol concentration of 3.8 g/L was obtained from microalgae by optimizing AP pretreatment conditions and the SSF approach (Harun et al 2010).…”

Poly-𝛽-hydroxybutyrate degradation by Aspergillus fumigates isolated from soil samples collected from Jeddah, Saudi arabia

“…Belal (2013) reported that the optimum pH for PHB hydrolase was at pH7, a second optimum pH appeared at pH 6 on agar plates. It is known also that the optimum pH for growth of Thermobifida fusca or T. bispora on mineral salt medium with glucose was pH 7.…”