Modeling and kinetic study of bio-ethanol production from soy protein concentrate by-product

Abstract

The aim of this work was to evaluate a non-agitated process of bioethanol production from soybean molasses and the kinetic parameters of fermentation using a strain of Saccharomyces cerevisiae (ATCC  2345). Kinetic experiment was conducted in medium with 30% (w v -1 ) of soluble solids without supplementation or pH adjustment. The maximum ethanol concentration was in 44 hours, the ethanol productivity was 0.946 g L -1 h -1, the yield over total initial sugars (Y 1 ) was 47.87%, over consumed sugars (Y 2 ) was 88.08% and specific cells production rate was 0.006 h -1 . The mathematical polynomial was adjusted to the experimental data and provided very similar parameters of yield and productivity. Based in this study, for one ton of soybean molasses can be produced 103 kg of anhydrous bioethanol.Keywords: alcoholic fermentation; bioethanol; soybean molasses; co-product valorization.Practical Application: Static fermentation showed high yield to ethanol production from soybean molasses.

Optimization of bioethanol production from soybean molasses using different strains of Saccharomyces cerevisiae

“…The bioethanol yield at the applied experimental conditions ranged in the interval of 0.350-0.372 g/g, which is about 70 % of the theoretical yield [23]. These results are similar to the results reported in literature for alcoholic fermentation of media containing soybean molasses [7,10]. The yeast strains applied in the present study were also used for bioethanol production from media based on effluents generated during sugar beet processing, including molasses, where somewhat higher values for the bioethanol concentration and bioethanol yield were achieved [29].…”

“…Soybean molasses is a sweet-sour brown viscous liquid obtained during the extraction of soybean proteins, which contains a high content of sugar (57 % dry weight), nitrogen, and other macro-and micronutrients. The sugars in molasses that can be converted into bioethanol are sucrose, glucose, and fructose, while approximately 47 % of the sugars in soybean molasses cannot be fermented by Saccharomyces cerevisiae [8,10].…”

Feasibility of bioethanol production from rice bran

“…The conversion factors Y P/S , Y X/S , and Y X/P varied between 0.48 and 0.58 g g -1 , 0.06 and 1.60 g g -1 , and 0.32 and 10.02 g g -1 , respectively (Table 4). For the Y P/S factor, runs 1 and 4 demonstrated the highest results (0.48 and 0.58 g g -1 ); these Y P/S values are greater than those cited in the literature (between 0.31 and 0.50 g g -1 ) for the production of bioethanol from sub-products, including sugarcane bagasse, soy protein concentrate, orange peel, and corn meal (Caldeirão et al, 2016;Gutiérrez-Rivera et al, 2015;Mojović, Nikolić, Rakin, & Vukasinović, 2006;Oberoi, Vadlani, Madl, Saida, & Abeykoon, 2010).…”

“…It may be observed from the response surface and contour plot that the highest concentrations of bioethanol were obtained by employing the maximum temperature and inoculum concentrations studied. Theoretically, 1.0 g of glucose should produce 0.511 g of bioethanol (Caldeirão, Tanaka, Ida, & Spinosa, 2016). However, in the CCRD-A 1.0 g of glucose resulted in a maximum of 0.29 g of bioethanol.…”

“…It should be possible to obtain approximately 35 g L -1 bioethanol using the DRB. However, during alcoholic fermentation, the presence of protein and lipids may reduce the performance of yeasts (Watanabe et al, Theoretically, 1.0 g of glucose should produce 0.511 g of bioethanol (Caldeirão, Tanaka, Ida, & Spinosa, 2016). However, in the CCRD-A 1.0 g of glucose resulted in a maximum of 0.29 g of bioethanol.…”