Earticle

Thin stillage is a liquid by-product of ethanol fermentation and contains various organic materials such as glycerol and lactic acid. Using thin stillage for butanol production, C. pasteurianum produced 6.2-7.2 g/L of butanol using 20 g/L of glycerol as the main carbon source at the initial pH of 4.9-6.9. Lactic acid in thin stillage acted as a buffering agent, maintaining the pH of the medium in the range of 5.7-6.5. Butanol yields were in the range of 0.31-0.44 g of butanol/g of glycerol and generally higher than those obtained with the thin stillage containing no lactic acid or a synthetic medium containing glycerol as the sole carbon source. These results demonstrate that thin stillage can be used for efficient butanol production without the addition of supplementary nutrients and continuous pH control.

Culture conditions for mass production of Chlorella schroteri, Dunaliella salina and Dunaliella sp. were optimized using response surface method (RSM). A central composite design, which was developed to facilitate the RSM, was applied to investigate the effects of initial pH, nitrogen sources and phosphate concentration on the cultivation of microalgae. The optimum growth conditions estimated from the design were: Chlorella schroteri (pH 7.2, ammonium 17mM, phosphate 1.2mM), Dunaliella salina (pH 7, nitrate 3.3mM, phosphate 0.0375mM) and Dunaliella sp. (pH 8, nitrate 3.7mM, phosphate 0.17mM). Culturing of the microalgae with the optimized conditions confirmed that the maximum growth rates were attained from the parameters. The specific growth rates(μmax) of Chlorella schroteri, Dunaliella salina and Dunaliella sp. were 0.99, 3.45 and 4.33/day, respectively. The biomass productivity of Chlorella schroteri, Dunaliella salina and Dunaliella sp. were 0.22, 0.46 and 0.23g dry cell weight/L/day, respectively.

The medium composition for butanol productivity by Clostridium pasteurianum DSM525 was optimized using response surface methodology (RSM). A fractional factorial design (FFD) for eight variables (phosphate buffer, MnSO4·H2O, MgSO4·7H2O, FeSO4·7H2O, (NH4)2SO4, yeast extract, cystein and MES) was applied to identify which variables affected butanol production. Among them, FeSO4·7H2O, (NH4)2SO4 and yeast extract were identified to be the most significant factors. Box-Behnken Model (BBM) was applied to estimate their values for the optimal medium compositions for butanol productivity. The composition of optimal medium for butanol productivity by C. pasteurianum DSM525 was determined to be 1.5 g/L of K2HPO4, 1.5 g/L of KH2PO4, 0.02 g/L of MnSO4·H2O, 0.25 g/L of MgSO4·7H2O, 0.06 g/L of FeSO4·7H2O, 7.4 g/L of (NH4)2SO4 and 5.0 g/L of yeast extract. The predicted butanol productivity by RSM (0.98 gL-1h-1) was verified by experiment using the optimal medium (1.01 gL-1h-1). Considering that the butanol productivity with the modified P2 (MP2) medium, a general butanol fermentation medium, was 0.71 gL-1h-1, butanol productivity was enhanced by 40% with the optimized medium composition resulted from RSM analysis.

A large number of fungi were isolated from soils of different regions and screened for cellulytic potential. One of the best cellulase producing fungal strains was selected and the cellulase production by the isolate from various lignocellulosic substrate such as flame grass, reed, empty fruit bunch, rice straw, barley straw were examined. The fungus was aerobically cultured in a flask containing broth medium containing the different lignocellulosic substrates and the culture filtrates were used as crude cellulases, xylanase, and pectinase. Among the five different substrates, barley straw produced the highest level of endocellulase, exocellulase, filter paperase, xylanase, pectinase. Although rice straw in the medium produced the highest level of β-glucosidase, barley straw was also comparable to the rice straw in the production of β-glucosidase. These results indicated that barley straw is an economic and efficient substrate for the production of cellulases, xylanase, and pectinase.

Butanol and ethanol could be good alternative biofuels for transportation. The bio- butanol and ethanol can be produced simultaneously in cultures of solventogenic Clostridium species through the acetonebutanol-ethanol (ABE) fermentation. For the isolation of microorganism capable of producing only butanol and ethanol without the acetone production, tidal flat samples were collected from seashore area of Tae-An, Korea. The isolated bacterium was designated Clostridium sp. nov. BS-5 and its 16S rDNA revealed 96% similarity to Clostirdium algidixylanolyticum SPL73T. Clostridium sp. nov. BS-5 produced acetone, ethanol, butanol, acetic acid, and butyric acid using glucose as a carbon source. To improve alcohol production, P2 medium modified with 3% sea salt was used and 0~50 g/L of yeast extract was initially added to investigate the effects of trace nutrients on two alcohol production. Ethanol and butanol concentration increased by the addition of yeast extract, up to 20 g/L. Clostridium sp. nov. BS-5 produced 14.71 g/L of alcohols with the yield of 0.54 g/g (0.20 g/L/hr). This result shows that Clostridium sp. nov. BS-5 is a promising new microorganism for two alcohol production.

Quantitative analysis of cellulose from hazardous plants for an industrial feedstock was investigated in this study. Various plant materials including Bur cucumber (Sicyos angulatus), Buffalo-Weed (Ambrosia trifida), White Sanicle (Eupatorium rugosum) obtained from where some parks were chosen as the ources of glucose. All samples were hydrolyzed by 1.5ml of 75% H2SO4 with 150mg of each sample for getting the glucose. When the samples were analyzed by spectrophotometer, the experimental results have shown that the stem of White Sanicle was the highest in the yield among the samples. Total content of glucose in stems of all plant materials reached up to 15% yield in all samples but in leaves revealed below 7% yield except for Bur cucumber (close to 12%). Glucose content of stem is higher than leap in all plants has shown in this study. These results indicate that cellulose obtained from hazardous plants can be used for alternative sources for bio-material.

From 21 strains, which is isolated from various environmental samples, D1 and E2 microbial strains were characterized and identified as Bacillus subtilis by analysis of 16S rDNA sequence and biochemical studies, and named as B. subtilis D1 and E2, which have high cellulase activities. The cellulase gene was cloned from each B. subtilis D1 and E2 genomic DNA by polymerase chain reaction (PCR). The amplified PCR products were ligated with the T&A cloning vector system and the constructed plasmids were transformed into E. coli DH5α. The sequence analysis of the insert DNAs revealed the identification of a 1,499-bp region containing cellulase open reading frame. According to cellulase gene sequence analysis, B. subtilis D1 had gene sequence similarity of 98% with B. subtilis strain AH18 cellulase gene (EF070194.1) and B. subtilis I15-endo-1,4-beta-glucanase (FJ464332.1). In case of B. subtilis E2, it had gene sequence similarity of 99% with B. subtilis strain AH18 cellulase gene (EF070194.1) and B. subtilis CMCase gene (D01057.1).

Marine biomass is considering as valuable resources for biofuels, such as volatile fatty acids (VFAs) by VFA platform. Marine seaweeds don’t have lignin and more soft, loose and flexible than lignocellulosic biomass. So they can be a good candidate for anaerobic digestion producing biofuels such as volatile fatty acid. In this study, acidogenesis of the solid residue Laminaria japonica and was studied. We have investigated the effects of various pretreatments on VFA production.

Marine microalgae, Spirulina maxima was extracted under high pressure and low temperature conditions at 500MPa and 60℃ for 5 and 15 min. The extraction yields from 5 min and 15 min extraction were observed as 25.3(%, w/w) and 26.1(%, w/w), respectively. It was found that the extracts for 15 min extraction had better skin immune activities than that the extract for 5 min. The extract for 15 min treatment significantly reduced the expression of Prostaglandin E2(PGE2) from CCD-986sk cells and also, increased nitric oxide production from macrophage. Prostaglandin E2(PGE2) production from UV-induced human skin cells was also greatly decreased down to 483 pg/ml in adding 1.0 mg/ml of the extract for 15 min treatment. The secretion of NO- from macrophage showed 23.8 μΜ, which was higher than process for 5 min as 19.8 μΜ. In conclusion, the most significant finding in this study was that S. maxima extracts under high pressure and low temperature process could have better skin immune activities, possibly by less damages of the components and higher extraction of active substances.

Two-phase partitioning bioreactors (TPPB) have attracted attention as an alternative technology for the treatment of gaseous contaminants because they have the capacity to treat high concentrations of Volatile Organic Compounds (VOCs). In this study, a strategic approach for the design of TPPBs has been formulated using, as a basis, a re-evaluation of extensive literature data available for the degradation of benzene by Achromobacter xylosoxidans Y234 in TPPBs with n-hexadecane as the partitioning phase. Our analysis began with an evaluation of the role of biomass in TPPBs given the unique characteristic of a biological steady state seen in TPPBs over extended periods of operation with continuous VOC feeding. By using a previously measured cellular maintenance coefficient, we have now predicted the mass of biocatalyst at biological steady state required for the satisfactory treatment of benzene as a function of its loading rate. Furthermore, by calculating the total oxygen transfer rate into a TPPB as a function of operating conditions (also related to the biomass level at biological steady state), we have subsequently determined the theoretical maximum benzene elimination rate that can be achieved without oxygen limitation under various agitation and aeration rates. The impacts of varying the phase volume ratio (organic:aqueous), aeration rate, and oxygen partition coefficient between the organic and aqueous phases were also examined, with the phase volume ratio being identified as a key parameter in both TPPB design and operation. The effect of the volume ratio on the mass transfer rate of benzene into the TPPB was also evaluated, and it was determined that TPPB performance can also be strongly influenced by the Henry’s law constant or solubility of a contaminant in water. Finally, we have integrated the elements of this analysis into a set of heuristic criteria that can serve as a set of guidelines for the design of TPPB systems for future VOC treatment applications.

This study was to increase glucose conversion yield of marine algae, Ulva pertusa Kjellman. Ultrasonification-assisted liquefaction process showed effecting destruction of polysaccharides under following conditions: 120W, 250W, 340W input power for 60min and at a frequency of 20kHz only by using water. The optimal condition of ultrasonification pretreatment was determined as 250W for 60min, having higher sugar yields as 12.2(% w/w), compared to 10.2~11(% w/w) for 700W and 1300W, which indicates that this process could increase the sugar conversion yields up to 10~15% of brown seaweed. Ulva pertusa Kjellman was estimated to contain ca. 6.7% (w/w) of cellulose and 16.8% (w/w) of hemicelluloses, and the hydrolysates from this process was also easily digested only 5FPU/ml of cellulase. About 97% of cellulose was converted into glucose under this condition, which implied that this ultrasonification-assisted liquefaction could be employed to effectively hydrolyze celluloses of marine algae. Consequently, the improvement is primarily attributed to the ultrasonification process for the enhanced enzyme activity of cellulose hydrolysis.

Because of its economical benefits, bioethanol production from cellulose resources need to be developed by efficient pretreatment processes. The complex pretreatment process composed of ultrasonification and microwave processes was used to hydrolyze corn stover by using only water, not acids or alkalis for environmental issue. Ultrasonification process at 20kHz was performed at 120W, 250W or 340W input power for 60min and 70℃, and microwave pretreatment at 2450MHz were applied with 700W, 1300W or 1700W input power for 12min. The optimal condition for ultrasonification pretreatment was determined as 120W for 60min, having sugar yields as 5.6(% w/w) of glucose and 18.6(% w/w) of xylose, respectively. The optimal condition for microwave pretreatment was also estimated as 1700W for 4min, yield in 8.9(% w/w) of glucose and 32.1(% w/w) of xylose, respectively. Furthermore, complex process at 120W for 60min followed by 1700W for 4min had 10.7(% w/w) of glucose and 39.3(% w/w) of xylose conversion yield, respectively. After treatments, the residue were easily hydrolyzed by low dose of cellulose as 5FPU/ml. About 64.6% of cellulose was converted into glucose after complex pretreatment process. These results indicate that the complex pretreatment could increase glucose conversion yields up to 15% only by using water.

In order to improve bio-ethanol productivity by various cultivation methods in this paper, the culture modes using food wastes, such as batch culture, high-cell-density fermentation, SSF(simultaneous saccharification and fermentation) by fill &draw, continuous culture by fill &draw were performed and their productivities were compared. SSFs by fill &draw were performed by continuous decompression with 1 L evaporator system, and by 10 L bioreactor without decompression. In addition, the continuous cultures by fill &draw mode using SFW(saccharafied food waste) medium were performed by changes of 40% culture broth with intervals of 12 hr(0.03/hr), 6 hr(0.07/hr), 3 hr(0.13/hr). Consequently, productivities of bio-ethanol were 2.52 g/L-hr and 1.30 g/L-hr in batch culture and high-cell-density fermentation, respectively. The productivies of SSF by fill &draw showed 2.24 g/L-hr and 2.03 g/L-hr in continuous decompression with 1 L evaporator and 10 L bioreactor without decompression, respectively. Also, the productivities in continuous culture by fill &draw modes showed 2.02 g/L-hr, 4.07 g/L-hr and 6.25 g/L-hr by medium change with intervals of 12 hr, 6 hr and 3 hrs, respectively. In conclusion, the highest ethanol productivity was obtained in the continuous culture mode by fill &draw with medium change of 40% by 3 hrs(0.13/hr) interval.

Chlorella sp. was grown with organic carbon source as glucose under mixotrophic conditions and CO2, to maintain mass amounts of biomass for biodiesel production. The cells were cultured in a 14 ℓ photo-bioreactor at 30℃ with illuminating light intensity of 30 μE/(m2s). CO2 was constantly supplied at a rate of 250 (ml/min) at an agitation speed of 150 rpm. The optimal concentration for mixotrophic growth was determined as 10 g/L. 10 g/L of glucose was found to be most proper carbon source, maintaining 5.3 (g-dry wt./L) of cell concentration and 17.2 (%, w/w) of total lipid for 90 days cultivation. Particularly, higher glucose concentration than 10 g/L showed the decrease of cell concentration and total lipid production. The cases of mixotrophic growth supplied glucose(10 g/L), cell concentration(5.3 g-dry wt./L) and total lipid production(17.2 %, w/w) were observed. For autotrophic growth, 2.3 (g-dry wt./L) and 10.3 (%, w/w) were observed for maximum cell concentration and total lipid production, respectively. After 45 days cultivation, nile red staining of Chlorella sp. grown with glucose was showed neutral lipids including hydrocarbons and triglycerides stained in yellow, while polar lipids did not almost exist. This study confirmed that optimal concentrations of glucose as an organic substrate to maintain high cell growth and lipid composition.

Thermostable fusant, Kluyveromyces marxianus CHY1612, was obtained by protoplast fusion between high ethanol fermentative Saccharomyces cerevisiae CHY1012 and thermostable Kluyveromyces marxianus CHY1703. AFEX pretreated barley straw at 150°C for 90 min was used in a simultaneous saccharification and fermentation (SSF) process using thermotolerant CHY1612. The SSF of 16% pretreated barley straw at 43°C gave a saccharification ratio of 90.5%, a final ethanol concentration of 38.5 g/L, and a theoretical yield of 91.2%. These results show that K. marxianus CHY1612 has potential for efficient lignocellulosic ethanol production through simultaneous saccharification and fermentation with further improvement of its fermentability.

In a previous study, we co-cultured the novel strain Bacillus licheniformis SGP1 with Clostridium tyrobutyricum ATCC 25755 for butyric acid production using sucrose as a carbon source in RCM medium. In this co-culture, B. licheniformis produces levansucrase enzyme in the medium which degrades sucrose into monosaccharides allowing C. tyrobutyricum to utilize them along with the lactic acid produced by B. licheniformis for butyric acid production. In this study, we wanted to determine the effect of different factors on the growth of this novel Bacillus strain and its levansucrase production and activity. Optimum pH was around 7.0. Optimum temperature for growth is 37⁰C. Enzyme production is decreased dramatically as the temperature rises from 30⁰C to 43⁰C and the reverse happens for enzyme activity. This enzyme has a molecular weight of 55 KDa. In fed-batch fermentation at pH 5.50 and temperature of 37⁰C, the co-culture could give a final butyrate concentration of 36 g/L with productivity equals 0.24 g/L/hr, while at 40⁰C, we could get 28.6 g/L and 0.34 g/L/hr respectively. Real time PCR experiment was done finally to determine the growth pattern of the two strains in the co-culture.

Five different varieties of potato(Go-woon, Ha-ryoung, Dae-seo, Jo-won, Ga-won) with different harvest time were used for ethanol production. The seed time of the potatoes was April 16, 2010. Fresh potato tubers(unpeeled) were washed, cut into 2×2×0.5 ㎝ cubes and mashed using a blender. After liquefying the potato mash using α-amylase(Termamyl SC), the liquefied mash was cooled and used for ethanol production by simultaneous saccharification and fermentation. Ha-ryoung harvested on July 9, 2010 produced the highest amount of ethanol(10.53%). By statistical analysis, the effectiveness of the contents of different components in potato tubers such as starch, moisture, crude protein, crude fat, crude fiber, and ash on the ethanol production were examined. The results showed that among the seven components, the starch and moisture contents affected the ethanol production positively and negatively, respectively.

Lactic acid is an important organic acid that is widely applied in the food, pharmaceutical, and cosmetic industries, due to its safety and optical activity. Many strains of Lactobacillus sp. were screened for the production of lactic acid (LA) in coffee ground waste and L. fermentum ATCC 23271 was selected for fermentation. Pretreatment experiments were conducted at various KOH concentrations, treatment time, treatment temperaturse, enzyme treatment time, and enzyme concentration. Lactobacillus fermentum produced 21 g/L. In this study, we studied the potential utilization of coffee ground waste for lactic acid production.

Scale-up of the process for conversion of fish wastes into liquid-fertilizer was examined in a 5-l ribbon-type reactor. Within 96 h after inoculation of autoclaved fish waste with 5.84×105CFU·ml-1 mixed microorganisms, the pH changed from 6.92 to 5.72, the cell number reached 7.28×105CFU·ml-1, and approximately 430 g of fish wastes was degraded. Analyses of a 96-h culture of inoculated fish waste indicated comparable fertilizing ability to commercial fertilizers in hydroponic culture and an amino acid content of 6.91 g·100g-1. Therefore, the scaled-up production was satisfactory with much higher fish-wastedegradationrate (3.61gh-1) than flask-scale production. The culture medium of fish wastes at room temperature was kept well from putrefaction for six months by addition of 1% lactate. Plant-scale production was necessary for commercialization according to cost-effectiveness analysis.

There are several pathways for secreting proteins in periplasm. Among them, twin arginine translocation (Tat) pathway express protein in periplasm after it is folded in cytoplasm. When organophosphorus hydrolase (OPH) is expressed with Tat signal sequence in Escherichia coli, inclusion body in cytoplasm is a major form. This can cause a possibility of low whole cell activity. In the present work, we investigated a strategy for overcoming this problem in a whole cell system by enforcing periplasmic secretion of OPH through chaperone co-expression. We co-expressed molecular chaperone including GroEL/ES with OPH. We found significant increase of OPH in a soluble form compared to that without chaperone and this might be due to increased protein folding. Furthermore, whole cell OPH activity of chaperone co-expressing cells was about 20 times greater than that of non-expressing cells. Consequently, whole cell activity can be enhanced by chaperone co-expression.

Lignocellulosic biomasses are in the spotlight as the non-edible resource for bioethanol production. However, it is more difficult to produce bioethanol from lignocellulosic biomass than starchy feedstock and has an economic problem such as treatment cost and enzyme cost. In this study, the pretreatment of rapeseed straw was performed using sodium hydroxide which is one of alkaline solvent and the reaction that converted rapeseed straw into sugars by enzymes was observed. The central composite design of response surface method was used to optimize the condition of enzyme hydrolysis of pretreated rapeseed straw. The result showed that the optimal condition of enzymatic hydrolysis of pretreated rapeseed straw for ethanol production is 39.25 FPU Cellulaclast 1.5L/g-glucan and 24.62 CBU Novozyme 188/g-glucan using response surface methodology. Finally, theoretical glucose yield was 91.28% after enzymatic hydrolysis.

Recently, EM is applied in various fields such as in industry, agriculture and environmental cleanup. Thus, quantitative analysis of EM is necessary as the characteristics and efficacy of EM depends on the distribution ratio of its main genera. Across the study of coexistence mechanisms of EM identifying co-culturing method is obviously necessary. Three strains that are used in this study are Rhodobacter sphaeroides, Lactobacillus plantarum, and Saccharomyces cerevisiae. Before co-culturing, each strains were grown in van Niel's yeast medium, MRS medium and YM medium respectively. It is possible to co culture of R.sphaeroides and S.cerevisiae. However, overgrowth of L.plantarum caused too high production of lactate, damaging R.sphaeroides by lowering pH. Therefore, to minimize the growth rate of L.plantarum, we have controlled the order and the amount of innoculation under illuminated conditions. The cell concentration of the bacteria was measured by spectrophotometer and cell growth analysis was observed on selective pressured plate counting. The coexistence of these strains were observed by using optical microscope.

Bioethanol from lignocellulosic biomass have economic and environmental advantages in comparison to bioethanol from sugar or starch. However, the physical and chemical barriers such as lignin inhibit the accessibility of enzyme to the cellulose substrate. In this study, sodium hydroxide pretreatment and sonicationassisted sodium hydroxide pretreatment were adopted for removing lignin. A central composite design of response surface method was used to optimize the condition of pretreatment and of rapeseed straw, in respect to sodium hydroxide concentration, treatment time and temperature. The result showed that the most optimal condition sodium hydroxide pretreatment of rapeseed straw for ethanol production is using 6.53% sodium hydroxide for 11.75 hours at 83.81℃ and 90.16% of theoretical glucose yielded. Whereas, the most optimal condition sonication-assisted sodium hydroxide pretreatment of rapeseed straw for ethanol production is using 7.81% sodium hydroxide for 3.23 hours at 75.75℃ and 91.85% of theoretical glucose yielded after pretreatment.

In recent years, many countries are focusing on "Biomass", a kind of renewable energy. Biomass can be made by four biorefinery platforms, and we choose volatile fatty acids(VFAs) platform. The VFAs platform does not need to add expensive enzyme and practice sterilization process. And as the VFAs platform applies marine biomass that does not have lignin, we can reduce pretreatment cost of lignin removal and choose a candidate of the anaerobic digestion process. In this study, anaerobic digestion of red algae (Gelidium amansii) that cannot lead to food shortage was studied in batch culture. We have researched the effect of acid, base and heat pretreatments on the VFAs production. We expect the best yield of the VFAs production on sample that is applied both acid and heat condition.

Kraft lignin is the major form of the lignin produced in the paper industry. The kraft lignin was degraded using thioacidolysis and by PAA (peracetic acid) produced by PFE (Pseudomonas fluorescens esterase). Both methods are known to selectively cleave β-aryl ether bonds in lignin. The degree of degradation was determined by comparing the molecular weight distribution before and after the treatment using SEC (size exclusion chromatography). The treatment with thioacidolysis and PFE decreased the molecular weight to 30% and 40% of the original kraft lignin, respectively. The thioacidolysistreated kraft lignin was further degraded by PFE, and SEC analysis showed that the molecular weight did not have a lot of changes, but the concomitant treatment showed that more lignin was degraded to much lower molecular weight products. These results suggest that the combinatorial treatment with thioacidolysis and PFE is an efficient method for the degradation of kraft lignin. Further investigation is required for the analysis of the small molecules produced by the degradation of kraft lignin.

Bio-based succinic acid production is more attractive than petrochemical process recently. Because It is expected that the independence on petroleum and carbon dioxide fixation effect during fermentation. But high production cost problem will be resolved for industrial application. In the previous study we have demonstrated that glucose obtained from sugar cane or corn was optimal carbon source for succinic acid production in M. succiniciproducens LPK7 (knock-out: ldhA, pflB, pta-ackA). But this biomass have shortcomings such as the requirement of farmland and food problem. On the other hand, marine biomass is advantage of vast ocean area, independence of food supply. Thus we have studied the possibility of using galactose obtained from marine biomass as carbon source. When the mixture ratio of galactose to glucose was 50:50, Yield was 84%, 102% for glucose and galactose respectively. these results suggest that marine biomass is valuable source for succinic acid production by M. succiniciproducens LPK7.

Water hyacinth has many advantages to product bioethanol, because it grows fast and is not edible [1]. Alkaline/oxidative pretreatment A/O pretreatment) using NaOH/H2O2 solution is known as most effective pretreatment method of water hyacinth [2]. In this study, we optimized A/O pretreatment conditions (solution concentration, reaction temperature) and analyzed component of each pretreatment sample for investigating effect of A/O pretreatment in many condition. In order to optimize the hydrolysis condition, Celluclast and Viscozyme 1.5L were applied at various enzyme concentrations and enzyme ratios. Ethanol production was performed using SHF, SSF and batch fermentation mode by Saccharomyces cerevisiae KCTC 7928. As a result, the most effective A/O pretreatment condition is NaOH concentration 7% (w/v) at 100℃ and H2O2 concentration 2%. Amount of glucose concentration is 18.29 (g/l). The yield of ethanol production was 0.33 (g/g- pretreatment). The concentration of ethanol was analyzed by HPLC with RI detector (flow rate 0.6ml/min, oven temperature 40℃).

Microalgae have believed as key bioresource for biofuel and valueadded product as well as CO2 mitigation. The hydrocarbon and carotene contents were determined to evaluate and to investigate of availability of hydrocarbon and carotenoid production by fresh water microalgal strains such as Chlamydomonas reinhardtii, Chlorella vulgaris, Nanochlorosis sp. In this study, strains were grown under ambient and CO2 supplement. Chlorella vulgaris showed higher growth rate under high CO2 with light than other strains. Hydrocarbon content determined by GC also was correlated with CO2 concentration and light intensity.

Hexanoic acid, six carbon and saturated fatty acid could be produced by bacteria like Clostridium kluyveri, Megsphaera elsdenii, and Clostridium sp. BS-1. In this study, we investigated optimization of hexanoic acid production by Clostridium sp. BS-1. To determine the effective factors for hexanoic acid production, fractional factorial design was used and concentration range of the factors was determined via steepest ascent method (SAM). Response surface methodology (RSM) was used for investigation of interactions between the factors and optimized hexaonoic acid production. The proposed solutions from RSM were verified experimentally. Yeast extract, FeSO4•7H2O, and butyric acid were determined as the effective factors.

Acetone-butanol-ethanol (ABE) fermentation by clostridia had lost its competitiveness since 1960s due to the dramatic increase in sugar price and the remarkable advances in chemical synthesis technologies. However, increasing demand for the use of renewable resources has drawn a renewed interest in the fermentative ABE production. It has well been known that the toxicity of solvents, in particular, butanol must be overcome for the commercialization of the fermentative ABE production. In general, temperature strongly affects the composition and structure of cellular membrane, which are relevant for the response to environmental stress, including solvents. In this study, the effect of temperature on the production of ABE was investigated by cooling down the temperature from 37℃ to 28~34 ℃ during the fermentation of Clostridium acetobutylicum, which is the most promising ABE producer. We found that the temperature shift during the period of the fermentation increased the total amounts of ABE in 6 L laboratory- and 300 L pilot-scale fermentors. This work was supported by the Eergy Efficiency &Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy.