Search

Lignocellulosic agricultural wastes are a potential feedstock for the synthesis of fuels and chemicals due to their low environmental cost, environmental friendliness, sustainability, and abundance. Therefore, corn byproducts are regarded as a valuable bioresource with multiple applications. In this study, platform chemicals, including levulinic acid (LA), formic acid (FA), and furfural (FF), were synthesized from corn husk by hydrothermal conversion using an acidic catalyst and a statistical Box-Behnken method. When selecting catalysts with MSA, H3PO4, H2SO4, HCl, and HNO3, the highest LA yield was obtained with methanesulfonic acid (MSA). At 170 °C, 12.5% biomass, 0.75 M MSA, and 40 min, the statistical optimization of corn husk conversion produced a yield of 18.0wt% LA based on biomass weight (57.75% based on carbohydrate content). Concurrently, an FA yield of 9.23wt% was achieved. At 170 °C, 5% biomass, 0.20 M MSA, and 15 min; however, a yield of 11.4wt% FF based on biomass weight (36.57% based on carbohydrate content) was obtained. LA and FA productions with combined severity did not fit the nonlinear sigmoidal model well. Nonetheless, the production of FF well-fitted the sigmoidal model with a high regression value. In corn waste biorefineries, the utilization of corn husk as bioresources and MSA as the catalyst for the synthesis of levulinic acid is well-understood. [ABSTRACT FROM AUTHOR]

In this study, ethanol was produced via thermal-acid hydrolysis, enzymatic saccharification, and fermentation from the red seaweed Eucheuma denticulatum as a biomass. Also, the removal and further recovery of 5-hydroxymethylfurfural (5-HMF) from hydrolysates were investigated. The thermal-acid hydrolysis produced 38.37 g/L monosaccharides and 6.55 g/L 5-HMF under the optimized condition of 13.7% (w/v) seaweed slurry and 479 mM H2SO4 at 121 °C for 54 min. More monosaccharide (6.43 g/L) was obtained from subsequent enzymatic saccharification using 8 U/mL of commercial enzyme C-Tec2 at 45 °C for 36 h. By detoxification, 88.0% of 5-HMF was removed from seaweed hydrolysates using a 1:1 ratio of polyethylenimine (PEI) to 5-HMF (g/g) at a pH of 11.0 for 15 min. Ethanol fermentation of E. denticulatum hydrolysate was performed using wild-type and galactose-adapted Saccharomyces cerevisiae. The ethanol concentration was maximized to 19.56 g/L (YEtOH = 0.43 g/g) by fermenting detoxified E. denticulatum hydrolysate with galactose-adapted S. cerevisiae Furthermore, for the valuation of 5-HMF (removed from hydrolysate) as a platform chemical, 85.6% of 5-HMF was recovered from the PEI-5-HMF solution by H2SO4 at pH 1.0. [ABSTRACT FROM AUTHOR]

Being an agarophyte, Gelidium is extensively exploited for its agar-producing capacity. However, the food value and medicinal importance of this red alga are not to be underestimated. The pharmacological properties of Gelidium species have potential for the pharmaceutical, nutraceutical and cosmeceutical industries. This review collects, identifies and analyzes comprehensively the studies that deal with the bioactive properties of Gelidium species in the last decade. The principal bioactive compounds of Gelidium include R-phycoerythrin, R-phycocyanin, alkaloids, terpenoids, tannins, flavonoids, saponins, coumarins, cardiac glycosides, and steroids. Gelidium in the form of extracts or isolated compounds have been reported to show antibacterial, antioxidant, anticancer, anti-inflammatory, anti-obesity, immunomodulatory, neuroprotective, and antidiabetic properties. Most of the evidence has been reported in various in vitro models. Therefore, further experiments using appropriate animal and human subjects are necessary to develop the preclinical findings into clinical use. The main challenge in developing bioactive compounds on a commercial scale is the sustainable supply of Gelidium biomass that requires integrated seaweed aquaculture through employing biotechnological approaches and effective utilization of industrial byproducts. [ABSTRACT FROM AUTHOR]

Eucheuma denticulatum is a red macroalgae with a high carbohydrate content. The fermentable sugars from E. denticulatum were obtained through sequential thermal acid hydrolysis, enzymatic saccharification, and detoxification. Thermal acid hydrolysis of E. denticulatum was optimized under the condition of 10% (w/v) slurry content and 300 mM HNO3 at 121 ℃ for 90 min. The maximum monosaccharide concentration after thermal acid hydrolysis was 31.0 g/L with an efficiency (ETAH) of 44.7%. By further enzymatic hydrolysis of pretreated biomass solution under 20 U/mL Cellic CTec2 at 50 ℃ and 160 rpm for 72 h, the maximum monosaccharide concentration reached 79.9 g/L with an efficiency of 66.2% (ES). To remove 5-hydroxymethylfurfural (5-HMF), a fermentation inhibitor, absorption using 2% activated carbon was performed for 2 min. Ethanol fermentation was performed using wild-type and high galactose-adapted strains of Saccharomyces cerevisiae, Kluyveromyces marxianus, and Candida lusitaniae. As a result, galactose-adapted strains showed higher ethanol production than wild-type strains. Especially, the fermentation result by adaptively evolved S. cerevisiae produced the highest ethanol of 37.6 g/L and with YEtOH of 0.48 g/g. Moreover, the transcript level of MIG1 in the galactose-adapted strain was slightly lower than that in the wild-type strain. The application of adaptive evolution of microorganisms was efficient for bioethanol production. [ABSTRACT FROM AUTHOR]

Microalgae are a widely available, renewable, and sustainable resource for bioenergy which may be used as a carbon-neutral alternative. We conducted hydrothermal conversion with MSA to obtain levulinic (LA) and formic acids (FA) from the lipid-extracted Chlorella vulgaris. Based on our analysis of reciprocal interactions between reaction conditions, maximum LA yields were obtained at high temperature, mid-range catalyst concentration, and mid-/long-range reaction time. Maximum FA yields were obtained at high temperature, high-range acid concentration, and short-/mid-range time. Using the Box-Behnken method to optimize the reaction, yields of 39.17% for LA and 20.19% for FA were obtained with 5% biomass, 0.5 M MSA at 195 °C for 35 min. Moreover, the effect of CSF on yield of LA and FA could be suitably represented by Sigmoidal equations with high R2. Overall, the application of lipid-extracted microalgae residue and eco-friendly MSA may prove useful for platform chemicals production. [ABSTRACT FROM AUTHOR]

This study is focused on the possibility of using crustacean waste shells for sustainable biofuels and chemical production. We investigated the synthesis of ethyl levulinate (EL) from glucosamine by the methanesulfonic acidcatalyzed hydrothermal reaction using Box-Behnken design. In the ethyl levulinate synthesis, higher water content highly inhibited the formation of EL. Among the reaction factors, reaction temperature, catalyst concentration, and reaction time positively affected the outcome more than substrate concentration. The optimized reaction conditions were 200 °C reaction temperature, 60 g/L substrate concentration, 0.75 M catalyst concentration, and 44.9 min. Under these conditions, a 22.76 mol% EL yield was achieved. These results suggest that crustacean waste shells can be used for renewable feedstocks to produce valuable chemicals and biofuels. [ABSTRACT FROM AUTHOR]

In this study, Pavlova lutheri, Chlorella vulgaris, and Porphyridium cruentum were cultured using modified F/2 media in a 1 L flask culture. Various nitrate concentrations were tested to determine an optimal nitrate concentration for algal growth. Subsequently, the effect of light emitted at a specific wavelength on biomass and lipid production by three microalgae was evaluated using various wavelengths of light-emitting diodes (LED). Biomass production by P. lutheri, C. vulgaris, and P. cruentum were the highest with blue, red, and green LED wavelength with 1.09 g dcw/L, 1.23 g dcw/L, and 1.28 g dcw/L on day 14, respectively. Biomass production was highest at the complementary LED wavelength to the color of microalgae. Lipid production by P. lutheri, C. vulgaris, and P. cruentum were the highest with yellow, green, and red LEDs' wavelength, respectively. Eicosapentaenoic acid production by P. lutheri, C. vulgaris, and P. cruentum was 10.35%, 10.14%, and 14.61%, and those of docosahexaenoic acid were 6.09%, 8.95%, and 11.29%, respectively. [ABSTRACT FROM AUTHOR]

A total monosaccharide concentration of 47.0 g/L from 12% (w/v) Gracilaria verrucosa was obtained by hyper thermal acid hydrolysis with 0.2 M HCl at 140°C for 15 min and enzymatic saccharification with CTec2. To improve galactose utilization, we overexpressed two genes, SNR84 and PGM2, in a Saccharomyces cerevisiae CEN-PK2 using CRISPR/Cas-9. The overexpression of both SNR84 and PGM2 improved galactose utilization and ethanol production compared to the overexpression of each gene alone. The overexpression of both SNR84 and PGM2 and of PGM2 and SNR84 singly in S. cerevisiae CEN-PK2 Cas9 produced 20.0, 18.5, and 16.5 g/L ethanol with ethanol yield (YEtOH) values of 0.43, 0.39, and 0.35, respectively. However, S. cerevisiae CEN-PK2 adapted to high concentration of galactose consumed galactose completely and produced 22.0 g/L ethanol at a YEtOH value of 0.47. The overexpression of both SNR84 and PGM2 increased the transcriptional levels of GAL and regulatory genes; however, the transcriptional levels of these genes were lower than those in S. cerevisiae adapted to high galactose concentrations. [ABSTRACT FROM AUTHOR]

In this study, bioethanol was produced from the seaweed Gelidium amansii as biomass through separate hydrolysis and fermentation (SHF) processes. The SHF processes examined in this study include thermal acid hydrolysis pretreatment, enzymatic saccharification, detoxification, and fermentation. Thermal acid hydrolysis pretreatment was conducted using H2SO4, with a slurry content of 8–16% and treatment time of 15–75 min. The optimal conditions for thermal acid hydrolysis pretreatment were 12% (w/v) seaweed slurry content and 180 mM H2SO4 at 121 °C for 45 min, at which 26.1 g/L galactose and 6.8 g/L glucose were produced. A monosaccharide (mainly glucose) was also obtained from the enzymatic saccharification of thermal acid hydrolysate using 16 U/mL Celluclast 1.5 L enzyme at 45 °C for 36 h. Detoxification was performed using the adsorption method with activated carbon, the overliming method with Ca (OH)2, and the ion exchange method with polyethyleneimine. Among those detoxification methods, activated carbon showed the best performance for hydroxymethylfurfural removal. Ethanol fermentation was performed using 12% (w/v) seaweed hydrolysate with Saccharomyces cerevisiae adapted to galactose as well as various detoxification treatments. [ABSTRACT FROM AUTHOR]

The seaweed industry has developed rapidly over the last decade, and carrageenan is the leading hydrocolloid in the seaweed industry. Approximately 57,500 t of carrageenan is produced annually throughout the world. As a consequence of the increase in carrageenan production, the enormous amount of waste resulting from the carrageenan industry has also increased. This study investigated the possibility of ethanol production using carrageenan solid waste from the carrageenan extraction of Kappaphycus alvarezii, the principal species used in the carrageenan industry. Optimum acid hydrolysis followed by enzymatic hydrolysis enhanced the production of both galactose and glucose. Fermentation of the enzymatic hydrolysate using Saccharomyces cerevisiae ATCC 200062 resulted in an ethanol yield of 13.8 g L−1. [ABSTRACT FROM AUTHOR]

Gracilaria verrucosa, red seaweed, is a promising biomass for bioethanol production due to its high carbohydrate content. The optimal hyper thermal (HT) acid hydrolysis conditions are 12% (w/v) G. verrucosa with 0.2 M H2SO4 at 130 °C for 15 min, with a severity factor of 1.66. This HT acid hydrolysis produces 50.7 g/L monosaccharides. The maximum monosaccharide concentration of 58.0 g/L was achieved with 96.6% of the theoretical monosaccharide production from 120 g dry weight/L G. verrucosa slurry after HT acid hydrolysis and enzymatic saccharification. Fermentation was carried out by removing an inhibitory compound and via yeast adaptation to galactose. Both Pichia stipitis and Kluyveromyces marxianus adapted to galactose were excellent producers, with the ethanol yield (YEtOH) of 0.50 and 29.0 g/L ethanol production. However, the bioethanol productivity with Pichia stipitis adapted to galactose is higher than that with Kluyveromyces marxianus adapted to galactose, being 0.81 and 0.35 g/L/h, respectively. The results from this study can be applied to industrial scale bioethanol production from seaweed. [ABSTRACT FROM AUTHOR]

Optimal conditions of hyper thermal (HT) acid hydrolysis of the Saccharina japonica was determined to a seaweed slurry content of 12% (w/v) and 144 mM H2SO4 at 160 °C for 10 min. Enzymatic saccharification was carried out at 50 °C and 150 rpm for 48 h using the three enzymes at concentrations of 16 U/mL. Celluclast 1.5 L showed the lowest half-velocity constant (Km) of 0.168 g/L, indicating a higher affinity for S. japonica hydrolysate. Pretreatment yielded a maximum monosaccharide concentration of 36.2 g/L and 45.7% conversion from total fermentable monosaccharides of 79.2 g/L with 120 g dry weight/L S. japonica slurry. High cell densities of Clostridium acetobutylicum and Clostridium tyrobutyricum were obtained using the retarding agents KH2PO4 (50 mM) and NaHCO3 (200 mM). Adaptive evolution facilitated the efficient use of mixed monosaccharides. Therefore, adaptive evolution and retarding agents can enhance the overall butanol and butyric acid yields from S. japonica. [ABSTRACT FROM AUTHOR]

Acetone, butanol, and ethanol (ABE) were produced following the separate hydrolysis and fermentation (SHF) method using polysaccharides from the green macroalgae Enteromorpha intestinalis as biomass. We focused on the optimization of enzymatic saccharification as pretreatments for the fermentation of E. intestinalis. Pretreatment was carried out with 10% (w/v) seaweed slurry and 270-mM H2SO4 at 121 °C for 60 min. Monosaccharides (mainly glucose) were obtained from enzymatic hydrolysis with a 16-U/mL mixture of Celluclast 1.5 L and Viscozyme L at 45 °C for 36 h. ABE fermentation with 10% (w/v) E. intestinalis hydrolysate was performed using the anaerobic bacteria Clostridium acetobutylicum with either uncontrolled pH, pH controlled at 6.0, or pH controlled initially at 6.0 and then 4.5 after 4 days, which produced ABE contents of 5.6 g/L with an ABE yield (YABE) of 0.24 g/g, 4.8 g/L with an YABE of 0.2 g/g, and 8.5 g/L with an YABE of 0.36 g/g, respectively. [ABSTRACT FROM AUTHOR]

We applied methanesulfonic acid (MSA) as a green catalyst to produce levulinic acid (LA) from monomeric sugars. To optimize reaction factors and assess the effect of reciprocal interactions, a statistical experimental design was applied. Optimized result of 40.7% LA yield was obtained under the following conditions: 60 g/L galactose, 0.4M MSA at 188 °C for 26.7 min. On the other hand, 66.1% LA yield was achieved under 60 g/L fructose and 0.4M MSA at 188 °C for 36 min conditions. For the effect of combined severity factor on the LA yield from galactose, the LA yield showed a peaked pattern, which was linearly increased until a CSF 3.2 and then diminished with a high CSF. Moreover, it was closely fitted to a non-linear Gaussian peak pattern with a high regression value of 0.989. These results suggest that MSA and galactose, derived from marine red macro-algae, can potentially be applied for the conversion into platform chemicals. [ABSTRACT FROM AUTHOR]

The optimal conditions for acetone-butanol-ethanol (ABE) production were evaluated using waste seaweed from Gwangalli Beach, Busan, Korea. The waste seaweed had a fiber and carbohydrate, content of 48.34%; these are the main resources for ABE production. The optimal conditions for obtaining monosaccharides based on hyper thermal (HT) acid hydrolysis of waste seaweed were slurry contents of 8%, sulfuric acid concentration of 138 mM, and treatment time of 10 min. Enzymatic saccharification was performed using 16 unit/mL Viscozyme L, which showed the highest affinity (Km = 1.81 g/L). After pretreatment, 34.0 g/L monosaccharides were obtained. ABE fermentation was performed with single and sequential fermentation of Clostridium acetobutylicum and Clostridium tyrobutyricum; this was controlled for pH. A maximum ABE concentration of 12.5 g/L with YABE 0.37 was achieved using sequential fermentation with C. tyrobutyricum and C. acetobutylicum. Efficient ABE production from waste seaweed performed using pH-controlled culture broth and sequential cell culture. [ABSTRACT FROM AUTHOR]

This study employed a statistical method to obtain optimal hyper thermal acid hydrolysis conditions using Gelidium amansii (red seaweed) as a source of biomass. The optimal hyper thermal acid hydrolysis using G. amansii as biomass was determined as 12% (w/v) slurry content, 358.3 mM H2SO4, and temperature of 142.6 °C for 11 min. After hyper thermal acid hydrolysis, enzymatic saccharification was carried out. The total monosaccharide concentration was 45.1 g/L, 72.2% of the theoretical value of the total fermentable monosaccharides of 62.4 g/L based on 120 g dry weight/L in the G. amansii slurry. To increase ethanol production, 3.8 g/L 5-hydroxymethylfurfural (HMF) in the hydrolysate was removed by treatment with 3.5% (w/v) activated carbon for 2 min and fermented with Pichia stipitis adapted to high galactose concentrations via separate hydrolysis and fermentation. With complete HMF removal and the use of P. stipitis adapted to high galactose concentrations, 22 g/L ethanol was produced (yield 0.50). Fermentation with total HMF removal and yeast adapted to high galactose concentrations increased the fermentation performance and decreased the fermentation time from 96 to 36 h compared to traditional fermentation. [ABSTRACT FROM AUTHOR]

As a potential renewable aquatic resource, chitosan is the second most abundant biopolymer. Methanesulfonic acid is a catalyst that is strongly acidic and biodegradable. We used chitosan and methanesulfonic acid to produce platform chemicals via an acid-catalyzed hydrothermal reaction. In the methanesulfonic acid-catalyzed hydrothermal conversion of chitosan, an optimal levulinic acid yield of 28.21±1.20% was achieved under the following conditions: 2% chitosan and 0.2 M methanesulfonic acid at 200 °C for 30 min. These results indicated that a combination of chitosan and methanesulfonic acid would be suitable for platform chemical production. [ABSTRACT FROM AUTHOR]

In this study, sulfamic acid-catalyzed pretreatment and subsequent enzymatic hydrolysis was conducted to produce biosugar from the marine macro-alga Gracilaria verrucosa. Sulfamic acid has dual active sites and is a green catalyst. Optimized sulfamic acid pretreatment at 130°C with 7.5% biomass and 100 mM sulfamic acid for 90 min yielded 39.9% total reducing sugar (TRS). Subsequent enzymatic hydrolysis yielded 69.1% TRS. These results indicate the potential of sulfamic acidcatalyzed pretreatment and subsequent enzymatic hydrolysis in producing biosugars using a biorefinery process. [ABSTRACT FROM AUTHOR]

Integrations of two-phase culture for cell growth and lipid accumulation using mixed LED and green LED wavelengths were evaluated with the microalgae, Phaeodactylum tricornutum, Isochrysis galbana, Nannochloropsis salina, and Nannochloropsis oceanica. Among the single and mixed LED wavelengths, mixed LED produced higher biomass of the four microalgae, reaching 1.03 g DCW/L I. galbana, followed by 0.95 g DCW/L P. tricornutum, 0.85 g DCW/L N. salina, and 0.62 g DCW/L N. oceanica than single LED or fluorescent lights at day 10. Binary combination of blue and red LEDs could produce the high biomass and photosynthetic pigments in the four microalgae. The highest lipid accumulation during second phase with the exposure to green LED wavelengths was 56.0% for P. tricornutum, 55.2% for I. galbana, 53.0% for N. salina, and 51.0% for N. oceanica. The major fatty acid in the four microalgae was palmitic acid (C16:0) accounting for 38.3-47.3% (w/w) of the total fatty acid content. [ABSTRACT FROM AUTHOR]

Bioethanol was produced using polysaccharide from soybean residue as biomass by separate hydrolysis and fermentation (SHF). This study focused on pretreatment, enzyme saccharification, and fermentation. Pretreatment to obtain monosaccharide was carried out with 20% ( w/ v) soybean residue slurry and 270 mmol/L HSO at 121 °C for 60 min. More monosaccharide was obtained from enzymatic hydrolysis with a 16 U/mL mixture of commercial enzymes C-Tec 2 and Viscozyme L at 45 °C for 48 h. Ethanol fermentation with 20% ( w/ v) soybean residue hydrolysate was performed using wild-type and Saccharomyces cerevisiae KCCM 1129 adapted to high concentrations of galactose, using a flask and 5-L fermenter. When the wild type of S. cerevisiae was used, an ethanol production of 20.8 g/L with an ethanol yield of 0.31 g/g consumed glucose was obtained. Ethanol productions of 33.9 and 31.6 g/L with ethanol yield of 0.49 g/g consumed glucose and 0.47 g/g consumed glucose were obtained in a flask and a 5-L fermenter, respectively, using S. cerevisiae adapted to a high concentration of galactose. Therefore, adapted S. cerevisiae to galactose could enhance the overall ethanol fermentation yields compared to the wild-type one. [ABSTRACT FROM AUTHOR]

The seaweed genus Gracilaria is a potential candidate for the production of bioethanol due to its high carbohydrate content. Gracilaria is abundant throughout the world and can be found in both wild and cultivated forms. Differences in the ecological factors such as temperature, salinity, and light intensity affecting wild and cultivated specimens may influence the biochemical content of seaweeds, including the carbohydrate content. This study aimed to investigate the proximate composition and potential bioethanol production of wild and cultivated G. gigas and G. verrucosa. Bioethanol was produced using separate hydrolysis fermentation (SHF), employing a combination of enzymatic and acid hydrolysis, followed by fermentation with Saccharomyces cerevisiae ATCC 200062. The highest carbohydrate content was found in wild G. gigas. The highest galactose and glucose contents (20.21 ± 0.32 and 9.70 ± 0.49 g L−1, respectively), as well as the highest production of bioethanol (3.56 ± 0.02 g L−1), were also found in wild G. gigas. Thus, we conclude that wild G. gigas is the most promising candidate for bioethanol production. Further research is needed to optimize bioethanol production from wild G. gigas. Domestication of wild G. gigas is a promising challenge for aquaculture to avoid overexploitation of this wild seaweed resource. [ABSTRACT FROM AUTHOR]

Worldwide, 9600 t of agar is produced annually. Meanwhile, 60% of the waste produced from the agar industry yearly do not get treated. Our present study aims to study the enzymatic saccharification of solid agar waste produced from two of the most widely used agarophytes in the agar industry, Gracilaria verrucosa and Gelidium latifolium. Gracilaria species are the most common raw material in the food grade agar industry, while Gelidium species are the most common raw material used for bacteriological and pharmaceutical purposes because of the high-quality agar that is produced from these species. Our results showed that waste generated from agar extraction still contained sugars which could be optimized by acid pretreatment and enzymatic saccharification. Gracilaria verrucosa resulted in a higher agar yield (35.15 ± 1.17%), but produced less agar waste (20.91 ± 0.43%) than G. latifolium. After sequential acid pretreatment and enzymatic saccharification of the agar waste, the agar waste hydrolysate of G. latifolium resulted in higher glucose, galactose, and ethanol production, and a higher ethanol yield (18.17 ± 0.75, 16.17 ± 2.07, and 10.83 ± 0.30 g L and 0.33 g g, respectively) than G. verrucosa. The results from our present study may be used to optimize biorefinery utilization of G. verrucosa and G. latifolium. [ABSTRACT FROM AUTHOR]

Conditions for ethanol production were evaluated using waste seaweed obtained from Gwangalli beach, Busan, Korea, after strong winds on January 15, 2015. Eleven types of seaweed were identified, and the proportions of red, brown, and green seaweed wastes were 26, 46, and 28%, respectively. Optimal pretreatment conditions were determined as 8% slurry content, 286 mM HSO for 90 min at 121 °C. Enzymatic saccharification with 16 units/mL Celluclast 1.5L and Viscozyme L mixture at 45 °C for 48 h was carried out as optimal condition. A maximum monosaccharide concentration of 30.2 g/L was obtained and used to produce ethanol. Fermentation was performed with single or mixed yeasts of non-adapted and adapted Saccharomyces cerevisiae KCTC 1126 and Pichia angophorae KCTC 17574 to galactose and mannitol, respectively. The maximum ethanol concentration and yield of 13.5 g/L and Y of 0.45 were obtained using co-culture of adapted S. cerevisiae and P. angophorae. [ABSTRACT FROM AUTHOR]

The physiological characteristics and the potential gluconolactone production of the gluconolactonase-deficient strain, Zymomonas mobilis ZM4 gnlΔ, were investigated via growth inhibitory assay and biotransformation of glucose and fructose into gluconolactone and sorbitol, respectively. The results of ethanol fermentation studies performed in the presence of high concentration of glucose (>200 g l) under fermentative or aerobic conditions indicated that a significant reduction of volumetric ethanol productivity from the strain of ZM4 gnlΔ was noticeable due to the reduced rates of specific growth, sugar uptake, and biomass yield as compared with those of the parental strain ZM4. The biotransformation prepared at pH 6.0 using the permeabilized cell indicated that gluconic acid from ZM4 gnlΔ was still produced as a major product (67 g l) together with sorbitol (65 g l) rather than gluconolactone after 24 h. Only small amount of gluconolactone was transiently overproduced up to 9 g l, but at the end of biotransformation, all gluconolactone were oxidized into gluconic acid. This indicated that autolysis of gluconolactone at the pH led to such results despite under gluconolactonase inactivation conditions. The physiological characteristics of ZM4 gnlΔ was further investigated under various stress conditions, including suboptimal pH (3.5~6.0), temperature (25~40 °C), and presence of growth inhibitory molecules including hydrogen peroxide, ethanol, acetic acid, furfural, and so forth. The results indicated that ZM4 gnlΔ was more susceptible at high glucose concentration, low pH of 3.5, and high temperature of 40 °C and in the presence of 4 mM HO comparing with ZM4. Therefore, the results were evident that gluconolactonase in Z. mobilis contributed to industrial robustness and anti-stress regulation. [ABSTRACT FROM AUTHOR]

This study examined the pretreatment, enzymatic saccharification, and fermentation of the red macroalgae Gracilaria verrucosa using adapted saccharomyces cerevisiae to galactose or NaCl for the increase of bioethanol yield. Pretreatment with thermal acid hydrolysis to obtain galactose was carried out with 11.7% (w/v) seaweed slurry and 373 mM HSO at 121 °C for 59 min. Glucose was obtained from enzymatic hydrolysis. Enzymatic saccharification was performed with a mixture of 16 U/mL Celluclast 1.5L and Viscozyme L at 45 °C for 48 h. Ethanol fermentation in 11.7% (w/v) seaweed hydrolysate was carried out using Saccharomyces cerevisiae KCTC 1126 adapted or non-adapted to high concentrations of galactose or NaCl. When non-adapted S. cerevisiae KCTC 1126 was used, the ethanol productivity was 0.09 g/(Lh) with an ethanol yield of 0.25. Ethanol productivity of 0.16 and 0.19 g/(Lh) with ethanol yields of 0.43 and 0.48 was obtained using S. cerevisiae KCTC 1126 adapted to high concentrations of galactose and NaCl, respectively. Adaptation of S. cerevisiae KCTC 1126 to galactose or NaCl increased the ethanol yield via adaptive evolution of the yeast. [ABSTRACT FROM AUTHOR]

A total monosaccharide concentration of 37.8 g/L and 85.9% conversion from total fermentable monosaccharides of 44.0 g/L from 110 g dw/L Eucheuma denticulatum slurry were obtained by thermal acid hydrolysis and enzymatic saccharification. Subsequent adsorption treatment to remove 5-hydroxymethylfurfural (5-HMF) using 5% activated carbon and an adsorption time of 10 min were used to prevent a prolonged lag phase, reduced cell growth, and low ethanol production. The equilibrium adsorption capacity ( q ) of HMF (58.183 mg/g) showed high affinity to activated carbon comparing to those of galactose (2.466 mg/g) and glucose (2.474 mg/g). The efficiency of cell growth and ethanol production with activated carbon treatment was higher than that without activated carbon treatment. Fermentation using S. stipitis KCTC7228 produced a cell concentration of 3.58 g dw/L with Y of 0.107, and an ethanol concentration of 15.8 g/L with Y of 0.48 in 96 h. [ABSTRACT FROM AUTHOR]

Optimal hyper-thermal (HT) acid hydrolysis conditions for Gelidium amansii were determined to be 12% (w/v) seaweed slurry content and 144 mM HSO at 150 °C for 10 min. HT acid hydrolysis-treated G. amansii hydrolysates produced low concentrations of inhibitory compounds and adsorption treatment using 3% activated carbon. An adsorption time of 5 min was subsequently used to remove the inhibitory 5-hydroxymethylfurfural from the medium. A final maximum monosaccharide concentration of 44.6 g/L and 79.1% conversion from 56.4 g/L total fermentable monosaccharides with 120 g dw/L G. amansii slurry was obtained from HT acid hydrolysis, enzymatic saccharification, and adsorption treatment. This study demonstrates the potential for butyric acid production from G. amansii hydrolysates under non-pH-controlled as well as pH-controlled fermentation using Clostridium acetobutylicum KCTC 1790. The activated carbon treatment and pH-controlled fermentation showed synergistic effects and produced butyric acid at a concentration of 11.2 g/L after 9 days of fermentation. [ABSTRACT FROM AUTHOR]

This work investigated the optimization of sugar and chemical formation from marine macro-green-alga Enteromorpha intestinalis by hydrothermal reaction and a statistical methodology. By this approach, the highest sugar and chemical yields were predicted as follows: glucose 10.42 %, xylose-mannose-galactose (XMG) 18.08 %, total reducing sugar (TRS) 28.61 % (reaction temperature 156 °C, catalyst amount 1.3 %, reaction time 11.4 min), levulinic acid 4.00 % (175.0 °C, 3.7 %, 35 min), 5-hydroxymethylfurfural 1.71 % (186.0 °C, 1.1 %, 37.9 min), and furfural 2.03 % (183.1 °C, 2.2 %, 10.7 min). In terms of the combined severity factor (CSF), the glucose, XMG, and TRS production decreased linearly with increasing CSF and to a high correlation. This application of a marine green-alga shows a high potential for production of fermentable sugars and chemicals suitable for biorefinement processes. [ABSTRACT FROM AUTHOR]

This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate ethanol production and bioadsorption with four red seaweeds, Gelidium amansii, Gracilaria verrucosa, Kappaphycus alvarezii and Eucheuma denticulatum. To produce ethanol, thermal acid hydrolysis, enzymatic saccharification and fermentation was carried out. After pretreatment, 38.5, 39.9, 31.0 and 27.5 g/L of monosaccharides were obtained from G. amansii, G. verrucosa, K. alvarezii and E. denticulatum, respectively. Ethanol fermentation was performed with Saccharomyces cerevisiae KCCM 1129 adapted to 80 g/L galactose. The ethanol productions by G. amansii, G. verrucosa, K. alvarezii and E. denticulatum were 18.8 g/L with Y = 0.49, 19.1 g/L with Y = 0.48, 14.5 g/L with Y = 0.47 and 13.0 g/L with Y = 0.47, respectively. The waste seaweed slurries after the ethanol fermentation were reused to adsorb Cd(II), Pb(II) and Cu(II). Using langmuir isotherm model, Cu(II) had the highest affinity for waste seaweeds with the highest q and electronegativity values among three heavy metals. [ABSTRACT FROM AUTHOR]

The extraction of lipid from Enteromorpha intestinalis was investigated. Among 13 types of organic solvent, the chloroform/methanol (2: 1, v/v) system obtained the highest content. Considering the lipid extraction procedure and extracted amount, the optimal solid/liquid ratio was 1: 50 (w/v). With increasing extraction temperature, the content was enhanced until 45 °C, after which it increased only slightly. Correspondingly, with increasing extraction time, the content linearly increased until 2.5 hr, after which it held steady. From a fatty acid compositional analysis of the lipid extracted from E. intestinalis, the content of palmitic acid and stearic acid was 39.85±1.19% and 14.61±0.80%, respectively. The unsaturated fatty acids (C18:1, C18:2 and C18:3) concentrations, meanwhile, were 0.3-3.2%. [ABSTRACT FROM AUTHOR]

The effects of free fatty acid (FFA) and moisture contents in palm oil, as well as working volume ratio on the production of biodiesel (fatty acid methyl esters; FAMEs), were investigated using palm oil and a non-catalytic supercritical process. FAME content obtained using anhydrous palm oil was 95.8% during the non-catalytic supercritical process. FAME content produced with 15% moisture content and 15% FFA content was 94.4% and 95.1% respectively, which was similar to that of anhydrous palm oil with no FFA. The non-catalytic supercritical process was not affected by FFA or moisture content in oil. By increasing working volume ratio, reaction temperature decreased from 340 °C to 260 °C at the same pressure, whereas FAME content increased from 69.9% to 95.5%. [ABSTRACT FROM AUTHOR]

To provide an option for the reutilization of high-salinity anchovy fishmeal wastewater (FMW), generated during the anchovy fishmeal manufacturing processes, its potential for biodegradation was assessed in 1-l five-neck flasks using a halotolerant and proteolytic microbial consortium. During the first 41 h of biodegradation, the pH, DO, ORP, and dry-sludge weight decreased as the total cell number of the microbial consortium increased steadily; the COD/TN ratios remained between 4.0 and 5.5, respectively, indicating the stable metabolic degradation of organic matter. The ORP tended to increase after 41 h, and the unpleasant fishy smell disappeared once positive ORP values were achieved. The removal percentages of COD and TN were 59.0 and 54.4 %, respectively, and the dry-sludge weight decreased from 115.5 to 68.0 g, with a degradation rate of 0.59 g h, during the 80 h experiment. The supernatant from the culture of the anchovy FMW at 70 h (culture supernatant) was phytotoxin-free, and the level of total amino acids was 8.04 g 100 g, comparable to that of commercial fertilizers. In hydroponic cultures containing red bean and barley, the culture supernatant demonstrated a good fertilizing ability. The culture supernatant also exhibited a high degree of antioxidant activity, with a 52.3 % hydroxyl radical-scavenging activity and 0.16 reducing power (at OD 700 nm). Moreover, the culture supernatant inhibited DNA damage from hydroxyl radicals, enhancing the reutilization value of anchovy FMW. This report presents the first description of high-salinity anchovy FMW possessing a high reutilization value potential both for agriculture and medicine. [ABSTRACT FROM AUTHOR]

A total monosaccharide concentration of 39.6 g/L, representing 74.0 % conversion of 53.5 g/L total carbohydrate from 80 g dw/L (8 % w/v) Gracilaria verrucosa slurry, was obtained by thermal acid hydrolysis and enzymatic saccharification. G. verrucosa hydrolysate was used as a substrate for ethanol production by 'separate hydrolysis and fermentation' (SHF). The ethanol production and yield ( Y) from Saccharomyces cerevisiae KCCM 1129 with and without adaptation to high galactose concentrations were 18.3 g/L with Y of 0.46 and 13.4 g/L with Y of 0.34, respectively. Relationship between galactose adaptation effects and mRNA transcriptional levels were evaluated with GAL gene family, regulator genes of the GAL genetic switch and repressor genes in non-adapted and adapted S. cerevisiae. The development of galactose adaptation for ethanol fermentation of G. verrucosa hydrolysates allowed us to enhance the overall ethanol yields and obtain a comprehensive understanding of the gene expression levels and metabolic pathways involved. [ABSTRACT FROM AUTHOR]

The β-glucosidase gene, bglC, was cloned from Bacillus sp. SJ-10 isolated from the squid jeotgal. Recombinant BglC protein overexpression was induced in Escherichia coli. The optimal pH and temperature of the enzyme, using p-nitrophenyl- β- d-glucopyranoside (pNPβGlc) as a substrate, were pH 6 and 40 °C, respectively. Enzymatic activity increased by 3.3- and 3.5-fold in the presence of 15 % NaCl and KCl, respectively. Furthermore, enzyme thermostability improved in the presence of NaCl or KCl. At 45 °C in the presence of salts, the enzyme was stable for 2 h and maintained 80 % activity. In the absence of salts, BglC completely lost activity after 110 min at 45 °C. Comparison of the kinetic parameters at various salt concentrations revealed that BglC had approximately 1.5- and 1.2-fold higher affinity and hydrolyzed pNPβGlc 1.9- and 2.1-fold faster in the presence of 15 % NaCl and KCl, respectively. Additionally, the Gibb's free energy for denaturation was higher in the presence of 15 % salt than in the absence of salt at 45 and 50 °C. Since enzymatic activity and thermostability were enhanced under high salinity conditions, BglC is an ideal salt-tolerant enzyme for further research and industrial applications. [ABSTRACT FROM AUTHOR]

In this work, the catalytic conversion of natural polymer chitosan to 5-HMF under low temperature hydrothermal condition was investigated. The highest 5-HMF yield of 12.1 wt% was obtained under the following conditions: 174 °C reaction temperature, 2.2 % catalyst amount, and 36.9 min reaction time. In the effect of combined severity, the 5-HMF production linearly increased to the combined severity factor of 3.07. By the way, higher combined severity factor can cause the over-degradation of 5-HMF. From this result, chitosan showed significant potential as a feedstock for the production of platform chemicals such as 5-HMF. [ABSTRACT FROM AUTHOR]

A total monosaccharide concentration of 59.0 g/L, representing 80.1 % conversion of 73.6 g/L total fermentable sugars from 160 g dw/L G. amansii slurry was obtained by thermal acid hydrolysis and enzymatic hydrolysis. Subsequent adsorption treatment using 5 % activated carbon with an adsorption time of 2 min was used to prevent the inhibitory effect of 5-hydroxymethylfurfural (HMF) >5 g/L in the medium. Ethanol production decreased with increasing salt concentration using C. tropicalis KCTC 7212 non-acclimated or acclimated to a high concentration of salt. Salt concentration of 90 psu was the maximum concentration for cell growth and ethanol production. The levels of ethanol production by C. tropicalis non-acclimated or acclimated to 90 psu high-salt concentration were 13.8 g/L with a yield (Y) of 0.23, and 26.7 g/L with Y of 0.45, respectively. [ABSTRACT FROM AUTHOR]

This study employed a statistical methodology to investigate the optimization of conversion conditions and evaluate the reciprocal interaction of reaction factors related to the process of red-algae Gracilaria verrucosa conversion to sugars (glucose, galactose), levulinic acid and 5-hydroxymethylfurfural (5-HMF) by acidic hydrolysis. Overall, the conditions optimized for glucose formation included a higher catalyst concentration than did those for galactose, and these conditions for galactose were similar to those for 5-HMF. Levulinic acid production, meanwhile, was optimized at a higher reaction temperature, a higher catalyst concentration, and a longer reaction time than was glucose, galactose or 5-HMF production. By this approach, the optimal yields (and reaction conditions) for glucose, galactose, levulinic acid, and 5-HMF were as follows: glucose 5.29 g/L (8.46 wt%) (reaction temperature 160 °C, catalyst concentration 1.92 %, reaction time 20 min), galactose 18.38 g/L (29.4 wt%) (160 °C, 1.03 %, 20 min), levulinic acid 14.65 g/L (18.64 wt%) (180.9 °C, 2.85 %, 50 min), and 5-HMF 3.74 g/L (5.98 wt%) (160.5 °C, 1 %, 20 min). [ABSTRACT FROM AUTHOR]

The waste product from salted Undaria pinnatifida (sea mustard) processing was fermented to produce bioethanol by Saccharomyces cerevisiae KCCM 1129 at laboratory and pilot development unit (PDU) scales. Thermal acidic hydrolysis of salted U. pinnatifida was conducted with 75 mM HSO at 121℃ for 60 min and the addition of 1.4 KNU/mL Termamyl 120L. A total monosaccharide concentration of 19.3 g/L and 32.2% conversion from 59.9 g/L total carbohydrate using 130 g dw/L salted U. pinnatifida were achieved. Ethanol fermentations in 5 and 500 L fermenters were carried out to produce 8.5 g/L of ethanol with an ethanol yield (Y) of 0.44 at 24 h and 7.9 g/L with Y of 0.41 at 18 h, respectively. The fermentation time of the PDU-scale reaction was reduced due to differences in the impeller type and geometry of the fermenters. [ABSTRACT FROM AUTHOR]

Unfortunately, the author name was wrongly published as Pailin Sukwang.instead of Pailin Sukwong. [ABSTRACT FROM AUTHOR]