The development of a biorefining strategy for the production of biofuel from sorghum milling waste

Abstract

The potential of using sorghum milling waste for the development of a biorefining strategy for the production of bioethanol was investigated. Both red and white sorghum were processed using a traditional Nigerian wet-milling process to sorghum flour. The sorghum milling waste, sorghum bran, was hydrolysed using both enzymatic and dilute acid hydrolysis to produce a generable fermentation feedstock. The hydrolysates were subsequently investigated for fermentative biofuel production. Following a hydrolysis step, a medium containing ~ 61 g/L glucose was obtained. Trace presence of inhibitors was detected in the hydrolysates and sufficient nitrogen content to support microorganism growth and bioethanol production. In test bioethanol production experiments using the sorghum milling waste derived hydrolysates only, 24.35 g/L bioethanol was produced by a yeast Kluyveromyces marxianus, equivalent to a yield of 0.15 gram bioethanol per gram of sorghum milling waste.

The Development of a Sorghum Bran-Based Biorefining Process to Convert Sorghum Bran into Value Added Products

“…In the model, an acid hydrolysis process was used, and the starch content in the sorghum bran was determined to be 52.96% (w/w). Some 0.73 million tons of bioethanol was estimated to be produced from 7.56 million tons of available sorghum crop [7]. If the acid hydrolysis process could be replaced by the integrated biorefining strategy reported in this study, a 10% increase in bioethanol production could be achieved (Figure 7A).…”

“…Ahmed El-Iman et al recently developed a model for estimating bioethanol production potential in Nigeria [7]. In the model, an acid hydrolysis process was used, and the starch content in the sorghum bran was determined to be 52.96% (w/w).…”

“…Approximately 0.85 million tons of bioethanol could be produced [6]. Ahmed El-Iman et al estimated the bioethanol production potential in Nigeria using sorghum bran [7], reaching the conclusion that 497 million US gallons of bioethanol could be produced, which equivalent to 17% of Nigeria’s transportation fuel use. Beside bioethanol, sorghum has also been investigated for biobutanol [8], biogas [9] and biohydrogen [10] production.…”

“…Although sorghum bran is one of the major agriculture waste streams, and contains high residual starch (up to 53% (w/w) [7]), the utilization of sorghum bran has not been fully investigated. In this study, a sorghum bran-based biorefining concept has been developed for glucoamylase production and using the resulting glucoamylase to hydrolyze sorghum bran to produce a sugar-rich generic fermentation medium.…”

Effect of fungal fermentation on proximate composition and <i>in vitro</i> performance of agrowastes used in animal feed

“…However, special efforts have been made to ensure that agricultural and industrial by-products, which are at times detrimental to man and animal health are utilized positively by converting them into value-added products. Some of these wastes include root tubers such as yam and cassava peels from food processing industries, and pineapple, citrus, banana, plantain and mango peels, coconut husks and shells, jatropha cake, corncobs, husks from fruit and vegetable processing industries and brans of cereals such as sorghum (Omojasola et al, 2008;Sulaiman et al, 2014;Aruna and Suneetha, 2016;Ahmed El-Imam et al, 2019).…”