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Abstract: The efficacy of extrusion pretreatment was evaluated by enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) with straw of rapeseed, Brassica napus, an agricultural residue. An acceptable pretreatment result was obtained at a barrel temperature of 165 °C, acid concentration of 20 g L−1, liquid feeding rate of 13.4 cm3 min−1, solid feeding rate of 1.0 g min−1, screw rotation speed of 6.3 rad s−1, and residence time of 10.2 min, with a yield of xmg, representing the sum of the corresponding hydrolyzed sugars; xylose, mannose and galactose, of 794.3 g kg−1 and a glucose release of 21.0 g kg−1. These were calculated to be 963.0 g kg−1 and 910.3 g kg−1 based on cellulose and hemicellulose recoveries,respectively. The highest enzymatic digestibility of 781.0 g kg−1was higher than that obtained from the batch pretreatment with dilute acid by 1.4-fold. The SSF process afforded an ethanol concentration of 16.0 g L−1, corresponding to an ethanol yield of 790 g kg−1 based on the total available cellulose in the pretreated rapeseed straw. [Copyright &y& Elsevier]

Abstract: This study compares the efficacy of soaking and percolation pretreatments with alkaline solutions for lignocellulosic biomass. The pretreated biomasses underwent enzymatic hydrolysis. Various biomasses such as rice straw and barley were pretreated by soaking processes in various alkaline solutions including sodium hydroxide, potassium hydroxide, aqueous ammonia and sodium carbonate. The enzymatic digestibility of rice straw and barley that had been pretreated by soaking in aqueous ammonia was 85% and 95%, respectively. Eucalyptus residue, Larix leptolepis and Pinus rigida exhibited relatively low enzymatic digestibility in the range of 3.2%–8.3%. Nevertheless, the enzymatic digestibility of pretreated eucalyptus residue was increased by five times compared to that of the initial biomass. In the pretreatment of eucalyptus residue, delignification was more than doubled with percolation pretreatment compared to soaking pretreatment. The enzymatic digestibility of the percolation pretreated eucalyptus residue was increased 12 times. [Copyright &y& Elsevier]

Abstract: The current status and challenges associated with the production and utilization of cellulosic ethanol in Korea are reviewed in this paper. Cellulosic ethanol has emerged as a promising option for mitigating Korea’s CO2 emissions and enhancing its energy security. Korea’s limited biomass resources is the most critical barrier to achieving its implementation targets for cellulosic ethanol. Efforts to identify new suitable biomass resources for cellulosic ethanol production are ongoing and intensive. Aquatic biomasses including macroalgae and plantation wastes collected in the Southeast Asia region have been found to have great potential as feedstocks for the production of cellulosic ethanol. R&D explorations into the development of technologies that can convert biomass materials to ethanol more efficiently also are underway. It is expected that cellulosic ethanol will be in supply from 2020 and that, by 2030, its use will have effectively reduced Korea’s total gasoline consumption by 10%. [Copyright &y& Elsevier]

Corn stover was pretreated with aqueous ammonia in a flow-through column reactor, a process termed ammonia recycled percolation (ARP). This method was highly effective in delignifying of the biomass, reducing the lignin content by 70–85%. Most lignin removal occurred within the first 20 min of the process. Lignin removal by ARP was further confirmed by FTIR analysis and lignin staining. The ARP process solubilized 40–60% of the hemicellulose but left the cellulose intact. The solubilized carbohydrate existed in oligomeric form. Carbohydrate decomposition during the pretreatment was insignificant. Corn stover treated for 90 min exhibited enzymatic digestibility of 99% with 60 FPU/g of glucan enzyme loading, and 92.5% with 10 FPU/g of glucan. The digestibility of ARP treated corn stover was substantially higher than that of α-cellulose. The enzymatic digestibility was related with the removal of lignin and hemicellulose, perhaps due to increased surface area and porosity. The SEM pictures indicated that the biomass structure was deformed and its fibers exposed by the pretreatment. The crystallinity index increased with pretreatment reflecting removal of the amorphous portion of biomass. The crystalline structure of the cellulose in the biomass, however, was not changed by the ARP treatment. [Copyright &y& Elsevier]

In this study, the chemical pretreatment method using ethanol organosolv with hydrogen peroxide was investigated to improve enzymatic saccharification of corn stover. The pretreatment method using ethanol with hydrogen peroxide in a flow-through reaction was proposed to lower the reaction severity such as the pretreatment temperature. With the same reaction time, the pretreatment process using organosolv (30 wt.% ethanol) containing 1 wt.% hydrogen peroxide at 150 °C resulted in a similar conversion yield as the result of the alkali pretreatment method using 15 wt.% aqueous ammonia at 170 °C. When corn stover was pretreated with 30 wt.% ethanol solution containing 5 wt.% hydrogen peroxide, a glucose conversion yield of 69.7 wt.% and glucose production of 23.8 g were achieved. [ABSTRACT FROM AUTHOR]

In this study, the optimum conditions for pretreatment of corn stover using organosolv were determined. The predicted optimum conditions, determined using the response surface methodology, were ethanol concentration of 56.6 wt %, reaction temperature of 187.5 °C, and 320 mL of liquid throughput. Moreover, the pretreatment using recycled organosolv was carried out under the predicted optimum conditions. The pretreatment effect of the organosolv decreased as the organosolv was reused in the pretreatment process. When performing pretreatment with the initial organosolv, enzymatic digestibility for glucan was 71.0%. The digestibility was reduced as low as less than 66% in the first reuse process. Nevertheless, when repeatedly reusing the organosolv, the glucan digestibility remained mostly stable. It was confirmed that organosolv can be reused in the flow-through pretreatment of corn stover. [ABSTRACT FROM AUTHOR]

Abstract: Rice straw was utilized for the cultivation of Phanerochaete chrysoporium to produce cellobiose dehydrogenase. The composition of the rice straw after fermentation was found to be 28.77% glucan, 19.05% xylan and 54.81% other lignin containing sugars. The glucan and xylan content decreased due to the consumption of glucan and xylan by P. chrysoporium. After fermentation, the rice straw waste was subjected to chemical pretreatment to remove lignin. The effect of dilute acid pretreatment was not notable because of the glucose loss. However, when the rice straw after fermentation was treated with aqueous ammonia, the composition changed to 44.73% glucan, 25.43% xylan and 29.52% other lignin containing sugars. The aqueous ammonia pretreatment was optimized and an ammonia concentration, reaction time and temperature of 20%, 6 h and 60 °C, respectively, were determined to be the optimal pretreatment conditions After removal of lignin, the initial reaction rate was increased to 0.009583 g/L s, which was about 3 fold higher than the rice straw after fermentation. X-ray diffractometry was performed to investigate the crystallinity index, and the XRD results showed that biological treatment and the combination of both biological treatment and chemical pretreatment decreased the crystallinity index. [Copyright &y& Elsevier]