Production of bioethanol from rice straw by simultaneous saccharification and fermentation of whole pretreated slurry usingSaccharomyces cerevisiaeKF-7

Abstract

Rice straw is one of the most abundant lignocellulosic waste materials worldwide, and it can serve as feedstock for bioethanol production. In this study, ethanol was produced from rice straw by simultaneous saccharification and fermentation (SSF) of the whole pretreated slurry with high solid load. Pretreatment of rice straw using 0.5% (w/w) H2SO4 was performed to increase the efficiency of enzymatic saccharification. Enzymatic saccharification and SSF of the whole pretreated slurry were subsequently performed to evaluate the inhibitory effect on enzymatic saccharification and the final ethanol yield. The result showed that pretreatment was the key for achieving high ethanol yield of the whole pretreated slurry. Rice straw pretreated at 170°C with a solid load of 15% exhibited efficient enzymatic saccharification. By the result of ethanol yields, no inhibitory effect was found when the whole pretreated slurry was subjected to SSF. The ethanol yield of SSF of the whole pretreated slurry was enhanced to 77.3%, compared with the glucose recovery efficiency of enzymatic saccharification of the washed pretreated rice straw, which was 74.4%. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 582–588, 2015

Ethanol production from dilute‐acid steam exploded lignocellulosic feedstocks using an isolated multistress‐tolerant Pichia kudriavzevii strain

“…Wang et al . () have reported that fermentation using the thermotolerant S. cerevisiae KF‐7 at 35°C achieved a theoretical yield of 77.3%, which was comparable to our results; however, the solid loading (20% (w/v) is equal to 19.58% (w/w) derived from the density 1.12 g/cm 3 of pretreated solid residue in dry basis) that we used and the ethanol titre (33.4 g p l −1 ) with P. kudriavzevii SI were higher than those with S. cerevisiae KF‐7, that is a solid loading of 15% (w/w) and 21.5 g p l −1 ethanol respectively. Although the concentration of acetic acid presented in their SSF process was similar with that in our study, the concentration of furans presented in their results (furfural 0.8 g l −1 and 5‐HMF 0.2 g l −1 ) was higher than that in our process (furfural 0.19 g l −1 ).…”

Inhibitor tolerance of a recombinant flocculating industrial Saccharomyces cerevisiae strain during glucose and xylose co-fermentation

“…Lignocellulosic hydrolysate of rape straw was prepared by diluted sulfuric acid treatment, as described previously. 28 Main inhibitors in the hydrolysate were acetic acid, formic acid, furfural, and 5-HMF, and the concentrations were 64.45 mM, 1.06 mM, 7.29 mM, and 7.61 mM, respectively. Besides, the concentration of total phenolic compounds was 0.3 g/L.…”

“… 22 Furfural, 5-HMF, acetic acid, and formic acid concentrations were determined using a LC-10AD VP HPLC (Shimadzu, Japan) under the following conditions: temperature, 65_C; mobile phase, 0.5 mM H 2 SO 4 at a flow rate of 0.8 mL/min. 28 The concentration of the total phenolic compounds was determined using a Folin–Ciocalteu assay as described by Guo et al, 29 with minor modification. One millliter of the hydrolysate was mixed with 5 mL of distilled water, 1.5 mL of Folin–Ciocalteu reagent (Sigma–Aldrich), and 2 mL of 10% (w/v) Na 2 CO 3 .…”

Kinetics of magnesium sulfite oxidation catalyzed by cobalt using a straw/sludge substrate as support

“…The catalytic activity increased when the straw content in the straw/sludge mixture was increased from 50% to 80% (Figure ). The main reason might be that the carbon content in the straw is higher than that in the sludge, which provided the framework of activated carbons . Moreover, a large number of oxygen‐containing functional groups was formed which facilitate the catalysis activity .…”