• Transactions of the Korean hydrogen and new energy society
• /
• v.13 no.4
• /
• pp.321-329
• /
• 2002

Clostridium butyricum, Lactobacillus amylophillus, Lactobacillus amylovorus, Lactobacillus acidophillus, AI-9 produced hydrogen and /or organic acids using glucose, lactose and starch at the anaerobic culture conditions. Cl. butyricum NCIB 9576 evolved 1,700 ml H2/L-culture broth and accumulated butyric acid, acetic acid, propionic acid and ethanol in its culture broth when lactose was used as a carbon source during 24 hrs of fermentation. L. amylovorus ATCC 33620 accumulated lactic and acetic acids and some reducing sugars when starch was used as a carbon source without hydrogen production. Instead of starch as a carbon source, L. amylovorus ATCC 33620 produced lactic acid from algal biomass during fermentation and the acid-heat or freeze-thaw pretreatment of algal biomass accelerate the lactic acid fermentation.

• Transactions of the Korean hydrogen and new energy society
• /
• v.29 no.1
• /
• pp.81-89
• /
• 2018

Fuel blend technique is one of the most effective way of using biomass to replace the coal. Many studies on combustion characteristics with coal and biomass blends have been conducted. In this study, char reactivity and emission characteristics of coal (Suek) and biomass (EFB) blends has been investigated by TGA and DTF to evaluate the applicability of the pre-treated (torrefaction, ash removal technology) EFB to pulverized coal boiler. In all blending cases, char reactivity improved as the blending ratio increases (10, 20, and 30%), especially torrefied EFB blended at 30%. Also, unburned carbon decreased as the blending ratio increases in all types of EFB. NOx emission showed the increase and decrease characteristics according to the content of fuel-N of raw EFB and torrefied EFB. But the amount of NOx emission at ashless EFB blends is greater than that of Suek despite of lower fuel-N. It indicated that co-firing effect of using the pretreatment biomass fuel is relatively better than those of the untreated biomass fuel about char reactivity and emission characteristics.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.3
• /
• pp.147-155
• /
• 2012

Switchgrass was selected as a promising biomass resource for bioethanol production through popping pretreatment, enzymatic saccharification and fermentation using commercial cellulase and xylanase, and fermenting yeast. The reducing sugar yields of popping pretreated switchgrass after enzymatic saccharification were above 95% and the glucose in thesaccharificaiton solution to ethanol conversion rate after fermentation with $Saccharomyces$ $cerevisiae$ was reached to 89.6%. Chemical compositions after popping pretreatment developed in our laboratory were 40.8% glucose and 20.3% xylose, with much of glucose remaining and only xylose decreased to 4.75%. This means that the hemicelluloses area broke off during popping pretreatment. FE-SEMexamination of substrate particles after popping pretreatment was showed fiber separation, and tearing and presence of numerous micro pores. These changes help explain, enhanced enzymatic penetration resulting in improved hydrolysis of switchgrass particles after popping pretreatment.

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.2
• /
• pp.145-162
• /
• 2019

This study aimed to increase the sugar and ethanol yield from the mengkuang plant biomass through biological and liquid hot water (LHW) pretreatment and their combination. The results showed that biological pretreatments with 5% inoculum of the fungus Trametes versicolor resulted in the highest alpha cellulose content incubated for 30 days, and 10% inoculum resulted in the lowest lignin content. LHW pretreatment decreased the hemicellulose content of pulps from 10.17% to 9.99%. T. versicolor altered the structure of the mengkuang pulp by degrading the lignin and lignocellulose matrix. The resulting delignification and cellulose degradation facilitate the hydrolysis of cellulose into sugars. The alpha cellulose content after biological-LHW pretreatment was higher (78.99%) compared to LHW-biological pretreatment (76.85%). Scanning electron microscopy analysis showed that biological-LHW combinated treatment degrades the cell wall structures. The ethanol yield for biological-LHW pretreated sample was observed 43.86% (13.11 g/L ethanol by weight of the substrate, which is much higher than that of LHW-biological pretreatment (34.02%; 9.097 g/L). The highest reducing sugar content about 45.10% was observed with a resulting ethanol content of 15.5 g/L at LHW pretreatment temperature of $180^{\circ}C$ for 30 min.

• Korean Chemical Engineering Research
• /
• v.47 no.1
• /
• pp.89-95
• /
• 2009

Because of high contents of cellulose (~37 wt%) and hemicellulose (~17%), rice straw seems to be a potential lignocellulosic biomass for production of bioethanol. In this study, Ammonia Recycled Percolation (ARP) pretreatment of rice straw was extensively investigated. In particular, the experimental study included the effects of temperature, reaction time and concentration of ammonia on compositions and enzymatic digestibility of the resulting solid residues; the ranges of pretreatment conditions were, in turn, $150{\sim}190^{\circ}C$, 10~90 min and 0~20 wt%. Through ARP pretreatment, the lignin content was reduced by as high as ~84% while 20~80% of the hemicellulose was also solubilized. The solid residue resulted from the pretreatment with 15 wt% aqueous ammonia solution at $170^{\circ}C$ for 90 mim showed as high as ~90% of digestibility with 15FPU/g of glucan enzyme loading. Supplement of xylanese to cellulase led to a notable enhancement of digestibility, indicating a discernable inhibitory role of hemicellulose. Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) were performed to obtain ethanol productions of 13.8 g/L (corresponding to 81% yield) and 15 g/L (corresponding to 89% yield), respectively.

• Clean Technology
• /
• v.18 no.1
• /
• pp.31-37
• /
• 2012

Biomass has become a major feedstock for bioenergy and other bio-based products because of its renewability and environmental benefits. Various researches have been done in the prediction of crucial characteristics of biomass, including the active utilization of spectroscopy data. Near infrared (NIR) spectroscopy has been widely used because of its attractive features: it's non-destructive and cost-effective producing fast and reliable analysis results. This work developed the multivariate statistical scheme for predicting weight loss profiles based on the utilization of NIR spectra data measured for six lignocellulosic biomass types. Wavelet analysis was used as a compression tool to suppress irrelevant noise and to select features or wavelengths that better explain NIR data. The developed scheme was demonstrated using real NIR data sets, in which different prediction models were evaluated in terms of prediction performance. In addition, the benefits of using right pretreatment of NIR spectra were also given. In our case, it turned out that compression of high-dimensional NIR spectra by wavelet and then PLS modeling yielded more reliable prediction results without handling full set of noisy data. This work showed that the developed scheme can be easily applied for rapid analysis of biomass.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.198-201
• /
• 2008

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of yellow poplar with doses of 0$\sim$450 kGy. The higher irradiation dose resulted in the more degradation of hardwood biomass not only from carbohydrates but also from lignin. This changes originated from the irradiation resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The more improvement on enzymatic hydrolysis by the irradiation was found in the xylan than in the cellulose of yellow poplar.

• Environmental Engineering Research
• /
• v.21 no.3
• /
• pp.265-275
• /
• 2016

In this study, the microalga Neochloris oleoabundans was cultivated in a sustainable manner using diluted anaerobic digestate to produce biomass as a potential biofuel feedstock. Prior to microalgae cultivation, the anaerobic digestate was characterized and several pretreatment methods including hydrogen peroxide treatment, filtration, and supernatant extraction were investigated and their impact on the removal of suspended solids as well as other organic and inorganic matter was evaluated. It was found that the supernatant extraction was the most convenient pretreatment method and was used afterwards to prepare the nutrient media for microalgae cultivation. A bench-scale experiment was conducted using multiple dilutions of the supernatant and filtered anaerobic digestate in 16 mm round glass vials. The results indicated that the highest growth of the microalga N. oleoabundans was achieved with a total nitrogen concentration of 100 mg N/L in the 2.29% diluted supernatant in comparison to the filtered digestate and other dilutions.

• KSBB Journal
• /
• v.27 no.2
• /
• pp.86-90
• /
• 2012

Ethanol fermentations were carried out using simultaneous saccharification and fermentation (SSF) and separated hydrolysis and fermentation (SHF) processes with monosaccharides from seaweed, Saccharina japonica (sea tangle, Dasima) as the biomass. The pretreatment was carried out by thermal acid hydrolysis with $H_2SO_4$ or HCl. Optimal pretreatment condition was determined at 10% (w/v) seaweed slurry with 37.5 mM $H_2SO_4$ at $121^{\circ}C$ for 60 min. To increase the yield of saccharfication, isolated marine bacteria Bacillus sp. JS-1 was used and 48 g/L of reducing sugar were produced. Ethanol fermentation was performed using SSF and SHF process with Pachysolen tannophilus KCTC 7937. The ethanol concentration was 6.5 g/L by SSF and 6.0 g/L by SHF.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.3
• /
• pp.317-323
• /
• 2022

Solid-state fermentation using hulled barley was carried out to produce enzymes and β-glucan. The one-factor-at-a-time experiments were carried out to determine the optimal composition of the basal medium. The modified synthetic medium composition in liquid-state fermentation was determined to be 70 g/l hulled barley, 0 g/l rice bran, 5 g/l soytone, and 6 g/l ascorbic acid. Optimal pretreatment conditions of hulled barley by solid-state fermentation were evaluated in terms of maximum production of fungal biomass, amylase, protease, and β-glucan, which were 1.26 mg/g, 31310.34 U/g, 2614.95 U/g, and 14.6% (w/w), respectively, at 60 min of pretreatment condition. Thus, the solid-state fermentation process was found to enhance the overall fermentation yields of hulled barley to produce high amounts of enzymes and β-glucan.