Bioethanol Production from Rice Straw in the MAFF Research Project, Japan

2009 ◽  
Vol 1219 ◽  
Author(s):  
Ken Tokuyasu
Keyword(s):  
Heat Treatment ◽  
Saccharomyces Cerevisiae ◽  
Rice Straw ◽  
Enzymatic Saccharification ◽  
Bioethanol Production ◽  
Chemical Pretreatment ◽  
Simple Method ◽  
Herbaceous Biomass ◽  
Free Glucose ◽  
Simultaneous Saccharification

AbstractRice straw is among the most abundant herbaceous biomass, and regarded as the central feedstock for bioethanol production in Japan. We found that significant amounts of soft carbohydrates (SCs), defined as carbohydrates readily recoverable by mere extraction from the biomass or brief enzymatic saccharification, exist in rice straw in the form of free glucose, free fructose, sucrose, starch, and β-1,3-1,4-glucan. Based on the finding, we proposed a simple method for bioethanol production from rice straw samples with SCs, by a heat treatment for sterilization and starch gelatinization, followed by simultaneous saccharification/fermentation with Saccharomyces cerevisiae. This method would offer an efficient process for bioethanol production without the aid of harsh thermo/chemical pretreatment step.

scholarly journals Evaluation of Alkali-Pretreated Soybean Straw for Lignocellulosic Bioethanol Production

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Seonghun Kim
Keyword(s):  
Sodium Hydroxide ◽  
Enzymatic Saccharification ◽  
Renewable Resource ◽  
Bioethanol Production ◽  
Yield Efficiency ◽  
Lignocellulosic Bioethanol ◽  
Acid Metabolites ◽  
Soybean Straw ◽  
Pretreated Biomass ◽  
Simultaneous Saccharification

Soybean straw is a renewable resource in agricultural residues that can be used for lignocellulosic bioethanol production. To enhance enzymatic digestibility and fermentability, the biomass was prepared with an alkali-thermal pretreatment (sodium hydroxide, 121°C, 60 min). The delignification yield was 34.1~53%, in proportion to the amount of sodium hydroxide, from 0.5 to 3.0 M. The lignin and hemicellulose contents of the pretreated biomass were reduced by the pretreatment process, whereas the proportion of cellulose was increased. Under optimal condition, the pretreated biomass consisted of 74.0±0.1% cellulose, 10.3±0.1% hemicellulose, and 10.1±0.6% lignin. During enzymatic saccharification using Cellic® CTec2 cellulase, 10% (w/v) of pretreated soybean straw was hydrolyzed completely and converted to 67.3±2.1 g/L glucose and 9.4±0.5 g/L xylose with a 90.9% yield efficiency. Simultaneous saccharification and fermentation of the pretreated biomass by Saccharomyces cerevisiae W303-1A produced 30.5±1.2 g/L ethanol in 0.5 L fermented medium containing 10% (w/v) pretreated biomass after 72 h. The ethanol productivity was 0.305 g ethanol/g dry biomass and 0.45 g ethanol/g glucose after fermentation, with a low concentration of organic acid metabolites. Also, 82% of fermentable sugar was used by the yeast for ethanol fermentation. These results show that the combination of alkaline pretreatment and biomass hydrolysate is useful for enhancing bioethanol productivity using delignified soybean straw.

Sign in / Sign up

Export Citation Format

Share Document