Production of bioethanol from sweet sorghum [Sorghum bicolor L.] juice using yeast isolated from fermented sweet sorghum juice

Abstract

BackgroundNonrenewable energies have been used as the major sources of energy in the world so far. However, they are not sustainable and environmentally friendly and there is an urgent need to search for alternative renewable sustainable energy sources. Sweet sorghum is a sugar rich plant that can be used as an important alternative source of bioenergy that is renewable with a low contribution to global warming without computing food security. This study aimed to investigate the potential of sweet sorghum juice for bioethanol production using yeast isolated from fermented sweet sorghum juice. MethodsSweet sorghum juice o Brix was determined using a digital refractometer.Yeasts isolated from fermented sweet sorghum juice were characterized using different biochemical tests. Potent yeast was used in the fermentation of sweet sorghum juice which was carried out at different fermentation parameters, mainly pH, temperature, and incubation period, using a completely randomized factorial design. Ethanol content was determined using a potassium dichromate solution. ResultsAbout 18 of yeast isolates were selected based on the sugar fermentation test for further characterization. The morphology and biochemical tests of the yeasts carried out suggest that all the yeast isolates have belonged to the genus Saccharomyces. The most ethanol tolerant yeast isolate, SJU14, was used for fermentation. ANOVA showed that, maximum ethanol content (18.765%) was produced at 30/26 o C, pH of 4.5, incubated for 96 hrs. ConclusionSweet sorghum juice found excellent source of potent yeasts and these yeasts have important industrial property such as able to grow at high ethanol and glucose concentration. Sweet sorghum juice can be used as an alternative substrate for bioethanol production to minimize the environmental threat caused by fossil fuels. Further research is recommended to strategically develop value-added utilization of sweet sorghum vis-à-vis improving food system and mitigating climate change.

Evaluation of sugar content and bioethanol production of Ethiopian local varieties “Nech Tinkish” and “Hawaye” sweet sorghum (Sorghum bicolor (L.))

“…The experiment was conducted in di replicates in 1000-ml flasks to which 250 SSJ, 2.5 g of (NH 4 ) 2 SO 4 , and 10 ml of (1 × 10 7 CFU/ml) yeast cells were added. Before fermentation, high ethanol and sugar concentration tolerant ethanol-producing SJU14 yeast was used for fermentation of SSJ [20]. To examine ethanol production from purified SSJ, ethanol-producing SJU14 was prepared and propagated to obtain a sufficient amount of yeast [36,40].…”

Improved Ethanol Production From Sweet Sorghum Through Pretreatment With Enzymes From Its Endophytes

“…Saccharomyces cerevisiae is commonly used in fermentation for ethanol production, and numerous studies have been conducted to enhance ethanol yield through yeast fermentation. (Sasaki et al 2015;Nuanpeng et al 2018;Kasegn et al 2023). However, transforming intricate cellulose and hemicellulose compounds into individual sugar units through biodegradation is still challenging, limiting their application further (Behera et al 2014).…”

Evaluation of Sugar Content and Bioethanol Production of Ethiopian Local Varieties “Nech Tinkish” and “Hawaye”Sweet Sorghum (Sorghum Bicolor (L.)

“…The experiment was conducted in di replicates in 1000 ml asks to which 250 SSJ, 2.5 g of (NH 4 ) 2 SO 4 , and 10 ml of (1 x10 7 CFU/ml) yeast cells were added. Before fermentation, high ethanol and sugar concentration tolerant ethanol-producing SJU14 yeast was used for fermentation of SSJ(Kasegn et al 2023). To examine ethanol production from puri ed SSJ, ethanol-producing SJU14 was prepared and propagated to obtain a su cient amount of yeast(Prasad and Dhanya 2011;Sasaki et al 2014).…”