• Clean Technology
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• v.29 no.4
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• pp.272-278
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• 2023

There is a lot of interest in methods for pollutants using adsorption, and recent research is being conducted to show that biochar can be used to remove organic and inorganic pollutants. In particular, wood waste as waste biomass requires a biomass recycling method, and a method to increase the adsorption capacity of biochar produced using wood waste is needed. Biochar is created by Hydrothermal carbonization (HTC) using, which uses low temperature and high pressure, has low energy consumption and does not require moisture removal pretreatment, and biochar is created through chemical activation using KOH, NaOH, and ZnCl₂ chemicals. The adsorption characteristics of biochar were determined by analyzing iodine adsorptivity, specific surface area, pore diameter, pore volume, pore distribution, and SEM according to the activation. The results of analyzing the selecting biochar by activating the biochar produced at HTC 300℃, 4 hr by KOH, NaOH, and ZnCl₂ chemicals, the specific surface area was 774~1.387 m²/g, showing a high specific surface area similar to activated carbon, and it was confirmed that micropores with an average pore diameter in the range of 21~24 Å were formed. As a result of SEM observation, the surface was uniform with a certain shape depending on activation. It was confirmed that one pore was developed and the number of pores increased.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.1922-1929
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• 2007

A simple whole-cell-based sensing system is proposed for determining the cell mass of H. pluvialis using ultraviolet fluorescence spectroscopy. An emission signal at 368 nm was used to detect the various kinds of green, green-brown, brown-red, and red H. pluvialis cells. The fluorescence emission intensities of the cells were highest at 368 nm with an excitation wavelength of 227 nm. An excitation wavelength of 227 nm was then selected for cell-mass sensing, as the emission fluorescence intensities of the cell suspensions were highest at this wavelength after subtracting the background interference. The emission fluorescence intensities of HPLC-grade water, filtered water, and HPLC-grade water containing a modified Bold's basal medium (MBBM) were measured and the difference was less than 1.6 for the selected wavelengths. Moreover, there was no difference in the emission intensity at 368 nm among suspensions of the various morphological states of the cells. A calibration curve of the fluorescence emission intensities. and cell mass was obtained with a high correlation ($R^2=0.9938$) for the various morphological forms of H. pluvialis. Accordingly, the proposed method showed no significant dependency on the various morphological cell forms, making it applicable for cell-mass measurement. A high correlation was found between the fluorescence emission intensities and the dry cell weight with a mixture of green, green-brown, brown-red, and red cells. In conclusion, the proposed model can be directly used for cell-mass sensing without any pretreatment and has potential use as a noninvasive method for the online determination of algal biomass.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2165-2172
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• 2017

Lignocellulose is now a promising raw material for biofuel production. However, the lignin complex and crystalline cellulose require pretreatment steps for breakdown of the crystalline structure of cellulose for the generation of fermentable sugars. Moreover, several fermentation inhibitors are generated with sugar compounds, majorly furfural. The mitigation of these inhibitors is required for the further fermentation steps to proceed. Amino acids were investigated on furfural-induced growth inhibition in E. coli producing isobutanol. Glycine and serine were the most effective compounds against furfural. In minimal media, glycine conferred tolerance against furfural. From the $IC_{50}$ value for inhibitors in the production media, only glycine could alleviate growth arrest for furfural, where 6 mM glycine addition led to a slight increase in growth rate and isobutanol production from 2.6 to 2.8 g/l under furfural stress. Overexpression of glycine pathway genes did not lead to alleviation. However, addition of glycine to engineered strains blocked the growth arrest and increased the isobutanol production about 2.3-fold.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.529-534
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• 2016

Bioethanol was produced using the separate hydrolysis and fermentation (SHF) method with macroalgal polysaccharides from the seaweed, Undaria pinnatifida as biomass. This study focused on the pretreatment, enzymatic saccharification, and fermentation of yeasts in co-culture. Ethanol fermentation with 14.5% (w/v) seaweed hydrolysate was performed using the yeasts, Saccharomyces cerevisiae KCTC 1126 alone, Pichia angophorae KCTC 17574 alone, and their co-cultures with the yeasts either adapted to mannitol or not. Among the combinations, the co-culture of non-adapted S. cerevisiae and P. angophorae adapted to mannitol showed high bioethanol production of 12.2 g/l and an ethanol yield ($Y_{EtOH}$) of 0.41. Co-culture in the SSF process was employed in this study, to increase the ethanol yields of 35.2% and reduction of 33.3% in fermentation time. These results provide suitable information on ethanol fermentation with marine seaweeds for bioenergy production.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.490-497
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• 2011

In this study, we determined optimal conditions for simultaneous saccharification and fermentation (SSF) using corncob biomass pretreated with oxalic acid. The effect of SSF temperature ($25.8{\sim}34.2^{\circ}C$) and agitation speed (80~220 rpm) were significant at a 99% confidence level in its effect on ethanol production. The highest ethanol production was expected when SSF was performed at $30^{\circ}C$, 170 rpm (22.5 g/L). The ethanol production was improved by mixture of yeast extract (1.25 g/L) and urea (1.25 g/L) as nitrogen source. However, addition of trace metal components and vitamin for SSF was not affected in the ethanol production. Optimal concentration of $KH_2PO_4$, $MgSO_4{\cdot}7H_2O$ for SSF was 1 g/L, 0.25 g/L respectively.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.29-35
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• 2017

BACKGROUND: This study was carried out to assess a biochemical methane potential of giant miscanthus (Miscanthus sacchariflorus) which was a promising candidate energy crop due to a high biomass productivity, in order to utilize as a feedstock for the biogas production. METHODSANDRESULTS: Giant miscanthus was sampled the elapsing drying time of 6 months after harvesting. TS (Total Solid) and VS (Volatile Solid) contents were 94.7 and 90.8%. And CP (Crude Protein), EE (Ether Extracts), and CF (Crude Fiber) contents of giant miscanthus were 1.4, 0.46, and 46.12%, respectively. In the organic composition of giant miscanthus, the NDF (Neutral Detergent Fiber) representing cellulose, lignin, and hemicellulose contents showed 86.88%, and the ADF (Acid Detergent Fiber) representing cellulose and lignin contents was 62.91%. Elemental composition of giant miscanthus showed 47.75%, 6.44%, 41.00%, and 0.28% for C, H, O, and N, respectively, and then, theoretical methane potential was obtained to $0.502Nm^3kg^{-1}-VS_{added}$. Biochemical methane potential was assessed as the range of $0.154{\sim}0.241Nm^3kg^{-1}-VS_{added}$ resulting the lower organic biodegradability of 30.7~48.0%. CONCLUSION: Therefore the development of pretreatment technology of the giant miscanthus was needed for the improvement of anaerobic digestability.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1819-1825
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• 2008

Degradation and glucose production from wood chips of white pine (Pinus strobus) and tulip tree (Liriodendron tulipifera) by several white rot fungi were investigated. The highest weight losses from 4 g of wood chips of P. strobus and L. tulipifera by the fungal degradation on yeast extract-malt extract-glucose agar medium were 38% of Irpex lacteus and 93.7% of Trametes versicolor MrP 1 after 90 days, respectively. When 4 g of wood chips of P. strobus and L. tulipifera biodegraded for 30 days were treated with cellulase, glucose was recovered at the highest values of 106 mg/g degraded wood by I. lacteus and 450 mg/g degraded wood by T. versicolor. The weight loss of 10 g of wood chip of L. tulipifera by T. versicolor on the nutrient non-added agar under the nonsterile conditions was 35% during 7 weeks of incubation, and the cumulative amount of glucose produced during this period was 239 mg without cellulase treatment. The activities of ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) of fungi tested did not show a high correlation with degradation of the wood chips and subsequent glucose formation. These results suggest that the selection of proper wood species and fungal strain and optimization of glucose recovery are all necessary for the fungal pretreatment of woody biomass as a carbon substrate.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.1-11
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• 2017

In this review, we focus on one of the most attractive biomaterials, microfibrillated cellulose (MFC). MFC, a type of nanocellulose, mainly originates from cellulose in lignocellulosic biomass. MFC represents one of incredible important natural resources due to its abundancy, renewability, and sustainability. MFC is produced through mechanical pretreatment, and it is composed of various sizes of microfibers, ranging from a few nanometers to a few micrometers. Because of the heterogenetic compositions of MFC, it possesses superior properties as a material, such as high surface area, high aspect ratio, and peculiar insolubility as a biomaterial. These properties allow MFC to be used in various bio-industries, from the traditional pulp industry to the high-tech food/bio/chemical/medical industries. However, it is difficult to use MFC on a commercial scale owing to the high energy input required during its production and the challenge of controlling its reactivity. Therefore, future studies should be focused on accurately characterizing MFC's surface morphologies, regulating its characteristics in a desirable direction, and standardizing proper guidelines for the analysis of surface morphologies its analysis.

• Journal of Life Science
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• v.29 no.1
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• pp.135-145
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• 2019

Zymomonas mobilis has been recognized as a potential industrial ethanologen for many decades due to its outstanding fermentation characteristics, including high ethanol tolerance, fast sugar uptake rate, and high theoretical ethanol yield. With the emergence of the postgenomic era and the recent announcement of DuPont's world largest cellulosic ethanol production process, research on this bacterium has become even more important to harness successful application not only for use in the bioethanol process but also in other biochemical processes, which can be included in bio-refinery. As an important industrial microorganism, Z. mobilis will likely be exposed to various stressful environments, such as toxic chemicals, including the end-product ethanol and fermentative inhibitory compounds (e.g., furan derivatives, organic acids, and lignin derivatives in pretreatment steps), as well as physical stresses, such as high temperature during large-scale ethanol fermentation. This review focuses on recent information related to the industrial robustness of this bacterium and strain development to improve the ethanol yield and productivity in the lignocellulosic ethanol process. Although several excellent review articles on the strain development of this bacterium have been published, this review aims to fill gaps in the literature by highlighting recent advances in physiological understanding of this bacterium that may aid strain developments and improve the ethanol productivity for lignocellulosic biomass.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.202-209
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• 1991

This study was carried out to examine seed germination, seedling growth, and biomass production of Eucommia ulmoides. The results were summarized as follows ; 1. Cold moist stratification at a refrigerator showed 60.3% of seed germination, which is the most effective among pretreatment methods. 2. In case of 1-0 seedlings, sixty seedlings per $1m^2$ was the most appropriate density, and the growth quality of seedlings differed significantly among densities. 3. Height growth showed continuous growth pattern and the maximum growth was shown during the period 21 June to 20 July, which corresponds 32.7% of total annual growth. 4. As tree age and DBH increased, the production of bark and leaf increased, however, its increment rate remarkably dropped down after ten years. 5. When tree age was ten years, the rate of bark volume showed the maximum value, 12.42%. 6. Dry weight of barks and leaves and bark volume were positively related to the growth of DBH and height. 7. As tree age increased, leaf area decreased, but the number of leaves increased.