• Journal of the Korean Wood Science and Technology
• /
• v.22 no.4
• /
• pp.7-12
• /
• 1994

In recent years, the municipal wastes recognized resources. This study was performed to survey the changes of main components of the pretreated(chemical, physical) lignocellulosic biomass. The result can be summerized as follows; In pulp fiber composition, newsprint and corrugating container were mainly consist of softwood fiber(tracheid). But computer print out and magazine had a large amount of hardwood fiber(wood fiber). And, carbohydrate content in the various lignocellulosic biomass increases as the following orders : Magazine < Newsprint < Corrugating container < Computer print out. In the chemical pretreatments for the delignification, sodium hypochlorite pretreatment was more effective than sodium hydroxide. By washing, ash content of lignocellulosic biomass was decreased. Physical pretreatments were less effective than chemical pretreatment for the delignification. On the other hand, in physical pretreatments, ash content of lignocellulosic biomass was the same tendency as in the chemical pretreatments.

• Korean Chemical Engineering Research
• /
• v.56 no.4
• /
• pp.453-460
• /
• 2018

Owing to rising oil prices and anthropogenic global warming, focused attempts are being made toward production of industrially important compounds by using renewable biomass. In this context, algal biomass as third-generation biomass is important because it doesn't compatible with food resource, has high yield, and helps abate greenhouse gases. Here, we investigate whether Undaria has the highest sugar content, which would make it the most suitable biomass for lactic acid production among the four algal biomasses tested. For effective pretreatment of Undaria, the response surface methodology was used. The amount of solid loaded and catalyst concentration were related to the extraction rate of total sugar. Lactic acid was produced by pretreatment of Undaria by using four Lactobacilli, and L. alimentarius and L. brevis were found to be suitable for lactic acid production.

• Journal of the Korean Wood Science and Technology
• /
• v.38 no.2
• /
• pp.149-158
• /
• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• Korean Journal of Medicinal Crop Science
• /
• v.26 no.2
• /
• pp.127-133
• /
• 2018

Background: The demand of recycling renewable agricultural by-products is increasing. Radiation breeding is a method used to improve saccharification efficiency. Thus, we investigated the effect of gamma ray irradiation on the pretreatment and enzymatic hydrolysis of the stalks of Senna tora, an important medicinal plants. Methods and Results: S. tora seeds were irradiated with gamma ray at doses of 100, 200, 300, and 400 Gy. In the pretreated biomass, glucan and lignin content were higher in the M1 ($1^{st}$ generations of irradiation) S. tora stalks than in the M2 ($2^{nd}$ generations of irradiation) stalks, this can be explained by the higher degradation rate in M1. After oxalic acid pretreatment, the concentration of total phenolic compounds (TPCs) in the hydrolysate increased in the gamma ray treated seeds. The highest relative increase rate in crystallinity in the pretreated biomass was observed in M1-400 Gy and M2-100 Gy. The cellulose conversion rate was higher in M1 than in M2, except for 200 Gy. Conclusions: Gamma ray irradiation at an appropriate dose can be used to improve the efficiency of pretreatment and enzymatic hydrolysis, thereby increasing biomass availability.

• KSBB Journal
• /
• v.27 no.3
• /
• pp.137-144
• /
• 2012

Among various pretreatment processes for bioethanol production, extrusion pretreatment, one of cheap and simple process was investigated to efficiently produce fermentable sugars from micro alga, Chlorella sp. The biomass was pretreated in a single screw extruder at five different barrel temperatures of 45, 50, 55, 60 and $65^{\circ}C$, respectively with five screw rotation speed of 10, 50, 100, 150 and 200 rpm. The pretreated biomass was reacted with two different hydrolyzing enzymes of cellulase and amyloglucosidase since the biomass contained different types of carbohydrates, compared to cellulose of agricultural by-products such wheat and corn stovers, etc. In general, higher glucose conversion yield was obtained as 13.24 (%, w/w) at $55^{\circ}C$ of barrel temperature and 100 rpm of screw speed conditions. In treating 5 FPU/glucan of cellulase and 150 Unit/mL of amyloglucosidase, ca. 64% of cellulose and 40% of polysaccharides in the micro alga were converted into glucose, which was higher yields than those from other reported data without applying an extrusion process. 84% of the fermentable sugars obtained from the hyrolyzing processes were fermented into ethanol in considering 50% of theoretical maximum fermentation yield of the yeast. These results implied that high speed extrusion could be suitable as a pretreatment process for the production of bioethanol from Chlorella sp.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.114.1-114.1
• /
• 2011

Bioenergy production from lignocellulosic biomass and agriculture wastes have been attracted because of its sustainable and non-edible source. Especially, canola is considered as one of the best feedstock for renewable fuel production. Oil extracted canola and its agriculture residues are reuseable for bioethanol production. However, a pretreatment step is required before enzymatic hydrolysis to disrupt recalcitrant lignocellulosic matrix. To increase the sugar conversion, more efficient pretreatment process was necessary for removal of saccharification barriers such as lignin. Alkaline pretreatment makes the lignocellulose swollen through solvation and induces more porous structure for enzyme access. In our previous work, aqueous ammonia (1~20%) was utilized for alkaline reagent to increase the crystallinity of canola residues pretreatment. In this study, significant factors for efficient soaking in aqueous ammonia pretreatment on canola residues was optimized by using the response surface method (RSM). Based on the fundamental experiments, the real values of factors at the center (0) were determined as follows; $70^{\circ}C$ of temperature, 17.5% of ammonia concentration and 18 h of reaction time in the experiment design using central composition design (CCD). A statistical model predicted that the highest removal yield of lignin was 54% at the following optimized reaction conditions: $72.68^{\circ}C$ of temperature, 18.30% of ammonia concentration and 18.30 h of reaction time. Finally, maximum theoretical yields of soaking in aqueous ammonia pretreatment were 42.23% of glucose and 22.68% of xylose.

• Microbiology and Biotechnology Letters
• /
• v.45 no.1
• /
• pp.51-56
• /
• 2017

Cellulosic biomass is a renewable source for biofuel production from non-edible biomass. An optimized pretreatment process is required for the efficient utilization of cellulosic biomass. Among various pretreatment processes, the use of ionic liquids has been reported recently. However, the residual ionic liquid after pretreatment acts as an inhibitor of microbial fermentation. Recently, we isolated mutant Saccharomyces cerevisiae strains resistant to the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) by using a directed evolutionary approach. When 3% [EMIM][Ac] was added to a medium containing 80 g/l of glucose, mutants D452-B2 and D452-S3 produced 35.6 g/l and 36.3 g/l of ethanol, respectively, for 18 h while the parental strain (S. cerevisiae D452-2) produced 1.3 g/l of ethanol. Thus, these mutant S. cerevisiae strains might prove advantageous when ionic liquids are used for biofuel production from cellulosic biomass.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.8 no.3
• /
• pp.179-182
• /
• 2003

Anaerobic fermentation was attempted to produce methane from the wood chip (Eucalyptus globulus). By the pretreatment of the wood chip using hot water with high temperature, NaOH, and steam explosion, the production of methane gas was enhanced. The pretreatment using Steam explosion resulted in more amount of methane gas produced than the treatment using either hot water or 1% (w/w) NaOH with high temperature, and the steam explosion at a steam pressure of 25 atm and a steaming time of 3 min was the most effective for the methane production. The amount of methane gas produced depended on the ratio of weight of Klason lignin, a high molecular weight lignin, in the treated wood chip.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.6
• /
• pp.1-7
• /
• 2014

Dissolving part of xylan and lignin in lignocellulosic biomass by base can be used as pretreatment technique. Cork oak was pretreated with sodium hydroxide solution and the pretreatment effects were evaluated with two critical factors - NaOH concentration and pretreatment temperature. Some of xylan and lignin were removed by base pretreatment. At $90^{\circ}C$ and 13% NaOH pretreatment, 22.0% of lignin and 78.8% of xylan removed by base treatment. Enzymatic hydrolysis of cork oak which was pretreated at higher temperature or concentration was further improved. After pretreatment of cork oak with 13% NaOH at $90^{\circ}C$, the conversion rate of cellulose to fermentable sugars were reached up to 91.3%. At ethanol fermentation with enzymatic hydrolysate from different pretreatment conditions, all enzymatic saccharification liquids were well fermented by Saccharomyces cerevisiae.

• Korean Chemical Engineering Research
• /
• v.61 no.3
• /
• pp.412-418
• /
• 2023

The surge in the oil prices, increasing global population, climate change, and waste management problems are the major issues which have led to the development of biofuels from lignocellulosic wastes. Cellulosic or second generation (2G) bioethanol is produced from lignocellulosic biomass via pretreatment, hydrolysis, and fermentation. Pretreatment of lignocellulose is of considerable interest due to its influence on the technical, economic and environmental sustainability of cellulosic ethanol production. In this study, furniture waste sawdust was subjected to alkaline peroxide (H₂O₂) for the production of reducing sugars. Sawdust was pretreated at different concentrations from 1-3% H₂O₂ (v/v) loadings at a pH of 11.5 for a residence time of 15-240 min at 50, 75 and 90 ℃. Optimum pretreatment conditions, such as time of reaction, operating temperature, and concentration of H₂O₂, were varied and evaluated on the basis of the amount of total reducing sugars produced. It was found that the changes in the amount of lignin directly affected the yield of reducing sugars. A maximum of 50% reduction in the lignin composition was obtained, which yielded a maximum of 75.3% total reducing sugars yield and 3.76 g/L of glucose. At optimum pretreatment conditions of 2% H₂O₂ loading at 75 ℃ for 150 min, 3.46 g/L glucose concentration with a 69.26% total reducing sugars yield was obtained after 48 hr. of the hydrolysis process. Pretreatment resulted in lowering of crystallinity and distortion of the sawdust after the pretreatment, which was further confirmed by XRD and SEM results.