Affordable and Clean Energy (SDG 7), Responsible Consumption and Production (SDG 12)
Acid hydrolysis of rice straw ( Oryza sativa ) followed by subsequent fermentation to yield bioethanol Raymond Jagessar * , Joel Persaud University of Guyana, Faculty of Natural Sciences, Georgetown, Guyana *E-mail: raymond.jagessar@uog.edu.gy Rice straw is a significant contributor to pollution when disposed by open-field burning in Guyana [1] . This study investigated bioethanol production using this substrate that is available in quantities excess of 1M metric tonnes. Prior to hydrolysis, a novel pretreatment method which involves grinding the substrate and mechanochemical disruption of the lignocellulosic matrix using pressurized water in a pressure cooker was explored. Dilute H 2 SO 4 hydrolysis followed by neutralization with NaOH and fermentation using Saccharomyces cerevisiae (baker’s strain) was adapted in a Separate Hydrolysis and Fermentation (SHF) process. The additive ZnSO 4 was noted to promote the fermentation process resulting in higher ethanol yields, 33.292 L (+ ZnSO 4 ) versus 31.235 L (- ZnSO 4 ) EtOH/MT rice straw. Results demonstrated the feasibility of producing substantial quantities of bioethanol from this substrate with the ability to obtain 28,596,042 L (- ZnSO 4 ) or 30,479,811 L (+ ZnSO 4 ) EtOH utilizing all the rice straw produced in Guyana in 2022. This can be blended with 285,960,420 L or 304,798,110 L gasoline to produce E10 fuel. Guyana imported 259,969,134 L of gasoline in 2022 [2] . Hence, bioethanol is sufficiently available to produce 100% E10 fuel for local consumption offering a sustainable alternative fuel source while mitigating environmental impacts from biomass burning. Key words: rice straw; acid hydrolysis; fossil fuel; Saccharomyces cerevisiae; bioethanol; Guyana. References 1. Satlewal, A., Agrawal, R., Bhagia, S., Das, P., & Ragauskas, A. J. (2017, October 17). Rice straw as a feedstock for biofuels: Availability, recalcitrance, and chemical properties. Biofuels, Bioproducts and Biorefining, 12(1), 83–107. https://doi. org/10.1002/bbb.1818 2. FAO GIEWS Country Brief on Guyana . (2024, July 23) https://www.fao.org/giews/countrybrief/country. jsp?code=GUY&lang=en
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