A genetically engineered Escherichia coli JM109 harboring pLF3 was used to produce a hybrid ex-tracellular β-glucanase. Starting with enzyme production medium, glycerol and yeast extract combined with NaNO3 were scre...A genetically engineered Escherichia coli JM109 harboring pLF3 was used to produce a hybrid ex-tracellular β-glucanase. Starting with enzyme production medium, glycerol and yeast extract combined with NaNO3 were screened to be the most suitable carbon and nitrogen source, respectively. Analysis of six components of the enzyme production medium by employing statistical optimization methods such as Plackett-Burman design and steepest ascent showed that yeast extract was the only significant variable and its best concentration for enzyme production was 12g·L-1. After optimization of the medium, 297.71U·ml-1 of β-glucanase activity in the medium and 352350U·g-1 of β-glucanase selectivity could be obtained, which were 14 and 72 folds higher than those ob-tained from original medium, respectively. Even higher enzyme activities were achieved by batch cultivations in a conventional stirred bioreactor on the optimized medium.展开更多
Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 o...Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50 ℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis. Product inhibition with different quantities of product added were studied in the initial several hours, during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.展开更多
Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae...Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae KM1195, S. cerevisiae KM7253 and co-culture of S. cerevisiae TISTR5048 and Candida tropicalis TISTR5045. The objective of this study was to assess the ethanol production from cassava stalks by dilute-acid pretreatment and enzymatic hydrolysis that were convertible into ethanol by mono-culture and co-culture of yeast strain. Cassava stalks 1.5% （w/v） in 0.1 M sulfuric acid was pretreated for 30 min at 135 ℃ under the pressure of 15 lb/inch2. The pretreated cassava stalk suspensions were neutralized to pH 5.5 for saccharification process. The enzyme solution （a-amylase, amyloglucosidase, cellulase, xylanase and pectinase solubilized in buffer pH 5.0） was used for hydrolysis ofpretreated cassava stalk at 50 ℃ for 24 h. The hydrolyaste was supplemented with additional nutrients. The culture was incubated at 30 ℃. The pretreatment of the stalk with dilute-acid resulted sugar yield of 0.57 g/g dry matter from enzymatic hydrolysis, which was higher than dilute-alkaline-pretreated and distilled water-pretreated stalk. The sugar hydrolysate was bioconverted to ethanol with separate hydrolysis and fermentation （SHF） and simultaneous saccharification and fermentation （SSF）. The highest ethanol yields of 98.43% and 95.29% were obtained in SHF and SSF, respectively by S. cerevisiae KM1195. The fermentation time of SSF process was 24-32 h shorter than that of the SHF （= 56 h）, but not significantly leading to difference in ethanol production （5.42 g/L-6.22 g/L for SSF; 5.9 g/L-6.23 g/L for SHF）.展开更多
Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitum...Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitumoral, antimicrobial and immunological properties. The aim of this work was to produce and to evaluate the biological properties of protein-bound polysaccharide complexes, extra intracellular （E-PPS and I-PPS）, extracted from P. ostreatus cultures, using agricultural sunflower wastes as carbon source. Three main compounds in the E-PPS and four main compounds in the I-PPS were identified by SEC-UV-RI-HPLC. These complexes of P. ostreatus present no toxicity in Artemia salina cultures, after 24 h of incubation. Antioxidant properties of the complexes were evaluated by radical scavenging activity using DPPH method and lipid peroxidation inhibition capacity, determined by erytbsocytes hemolysis. Additionally, E-PPS and I-PPS extracts revealed capacity to mimetize superoxide dismutase and catalase enzymatic activities. The hepatoprotector effect of E-PPS extracts in Wistar rats was evaluated by AST, ALT, ALP and y-GT activities, showing capacity to reduce the liver damage induced by ethanol-administration. This hepatoprotective effect is equivalent to that observed by silymarin, a standard drug. Our results suggests that the extracts of E-PPS and I-PPS produced by P. ostreatus cultures, using agricultural sunflower wastes as main carbon source, can be used as an important source of bioactive compounds with potential medicinal value.展开更多
Cherry cultivar Misri （Bigarreau Noir Grossa） was used for making candy. Pitting of fruit was done manually and KMS （0.2%） was added for bleaching. The fruit was pretreated using 4 levels of CaCl2 （Co = 0%, C1 = ...Cherry cultivar Misri （Bigarreau Noir Grossa） was used for making candy. Pitting of fruit was done manually and KMS （0.2%） was added for bleaching. The fruit was pretreated using 4 levels of CaCl2 （Co = 0%, C1 = 1%, C2 = 1.5%, C3 = 2%） and stored in jars for 4 weeks. Thereafter, application of colour was done using Erythrosine （0.05%） followed by dipping pitted fruits in sugar syrup for 24 hours. The samples were treated with 4 levels of citric acid （To = 0%, Tl = 1%, T2 = 1.5%, T3 = 2%） and then concentrated subsequently till desired TSS of 70~ Brix was attained. The samples were dried in cabinet drier at 80 ±20 ℃till constant moisture was attained. The product was packed in polyethene pouches and stored under ambient storage conditions. Results revealed that there was gradual increase in reducing sugars （%）, total sugars （%） during storage while as moisture content （%） decreased. The product developed was found economically profitable and viable for commercial production.展开更多
Sugarcane shoots and leaves consist of 35.2% cellulose, 23.43% hemicellulose, 12.6% lignin and 6.59% ash on dry solid （DS） basis and have the potential to serve as low cost feedstocks for ethanol production. To impr...Sugarcane shoots and leaves consist of 35.2% cellulose, 23.43% hemicellulose, 12.6% lignin and 6.59% ash on dry solid （DS） basis and have the potential to serve as low cost feedstocks for ethanol production. To improve the enzymatic digestibility of these biomass and bioethanol production, three pretreatment methods had been investigated and compared, including： （1） 2% w/v NaOH solution autoclaving pretreatment; （2） 2% w/v H2SO4 solution autoclaving pretreatment and （3） two steps of 2% w/v NaOH solution autoclaving followed by 2% w/v H2SO4 solution autoclaving pretreatment. Among them, the best result for ethanol production was obtained when 15 g DS of sugarcane shoots and leaves was pretreated by using two step of 2% w/v NaOH solution autoclaving followed by 2% w/v H2SO4 solution autoclaving. The highest ethanol concentration 30.40 g/L （92.65% in fermentation efficiency） was obtained from reducing sugar 89.25 g/L at 48 h. Moreover, the washing step of solid residue after pretreatment could reduce furfural and hydroxymethylfurfural （HMF） in all pretreatment methods when compared to unwashing solid residue after pretreatment.展开更多
[ Objective] The aim was to improve the saccharification of wheat bran cellulose. [ Method] Taking the wheat bran as raw materials, and using orthogonal method, the effects of acid concentration, temperature, times an...[ Objective] The aim was to improve the saccharification of wheat bran cellulose. [ Method] Taking the wheat bran as raw materials, and using orthogonal method, the effects of acid concentration, temperature, times and substrate concentration on the saccharification were investigated. [ Result] The influence of temperature on the acid treatment of the sacchadfication of wheat bran cellulose was significant. Influences of acid concentration on the hydrolysis were distinct. Influences of time and substrate concentration were insignificant. The optimal pretreatment conditions were 1.5% of sulfuric acid concentration and 0. 067 g/ml of substrate concentration at 100℃ in three hours. Under this condition, the sugar concentration was 38.137 mg/ml, and the hydrolysis rate reached 51.485%. [ Conclusion] The study improved the saccharification of wheat bran cellulose, which provided theoretical basis for the application of wheat bran industrial process.展开更多
L-（＋）-lactic acid production was studied by immobilized Lactobacillus rhamnosus TISTR108 on crude pectin from Krung Kha Mao （Cissampelospareira L.） leaves. Central composite design was employed to determine the m...L-（＋）-lactic acid production was studied by immobilized Lactobacillus rhamnosus TISTR108 on crude pectin from Krung Kha Mao （Cissampelospareira L.） leaves. Central composite design was employed to determine the maximum lactic acid production of 45.40 g/L in predicted model （Y = 43.98 - 2.43X1 ＋ 1.02X2 ＋ 2.96X3 - 8.72X1^2 - 3.99X2^2 - 1.74X3^2） with the factors at 5.9 of cultural medium pH, 37.6 ℃ of process temperature and 202 rpm of liquid agitation. Statistical analyses demonstrated very high significance for the regression model fitted the data adequately and explained the lactic acid production, since the F-value computed 54.89 was much higher than the tabulated F-value 2.08 for the lactic acid production at 5% level for linear and quadratic polynomial regression models. The highest experimental lactic acid production was 46.91 g/L at 72 h of fermentation.展开更多
Soil salinization and non-point source pollution are among the most important and widespread environmental problems in European Mediterranean regions. Sweet sorghum （Sorghum bicolor （L.） Moench var. saccharatum） i...Soil salinization and non-point source pollution are among the most important and widespread environmental problems in European Mediterranean regions. Sweet sorghum （Sorghum bicolor （L.） Moench var. saccharatum） is a moderate to high salinity tolerant crop with low water and nutrient needs, seen as an alternative to grow in the water scarce regions. A three-year multifactorial study was conducted in southern Portugal to evaluate the combined effects of saline water and nitrogen application on the dry biomass （total, stems, and leaves）, sugar content （total reducing sugars and sucrose eontents） and sugar yield （here defined as the product of total reducing sugars and stems dry biomass） functions of sweet sorghum. Sorghum dry biomass and sugar yield showed diminishing returns for each incremental change of nitrogen. The use of saline irrigation waters also led to yield reduction. Exception was sucrose content which increased with increasing levels of sodium in the soil. Nitrogen need decreased as the amount of sodium applied increased. Stem dry biomass, sucrose content, and sugar yield progressively increased with progress in the experiment. The effect could be attributed to the increase of the amount of irrigation applied throughout the years, thus increasing the leaching fraction which promoted salt leaching from the root zone, reduced the salinity stress, increased plant transpiration, nitrogen uptake and biomass yield.展开更多
Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, ...Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.展开更多
基金Supported by the National Natural Science Foundation of China (No.20306025)the Xiamen Science and Technology Pro-ject (No.3502Z20055017).
文摘A genetically engineered Escherichia coli JM109 harboring pLF3 was used to produce a hybrid ex-tracellular β-glucanase. Starting with enzyme production medium, glycerol and yeast extract combined with NaNO3 were screened to be the most suitable carbon and nitrogen source, respectively. Analysis of six components of the enzyme production medium by employing statistical optimization methods such as Plackett-Burman design and steepest ascent showed that yeast extract was the only significant variable and its best concentration for enzyme production was 12g·L-1. After optimization of the medium, 297.71U·ml-1 of β-glucanase activity in the medium and 352350U·g-1 of β-glucanase selectivity could be obtained, which were 14 and 72 folds higher than those ob-tained from original medium, respectively. Even higher enzyme activities were achieved by batch cultivations in a conventional stirred bioreactor on the optimized medium.
文摘Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50 ℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis. Product inhibition with different quantities of product added were studied in the initial several hours, during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.
文摘Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae KM1195, S. cerevisiae KM7253 and co-culture of S. cerevisiae TISTR5048 and Candida tropicalis TISTR5045. The objective of this study was to assess the ethanol production from cassava stalks by dilute-acid pretreatment and enzymatic hydrolysis that were convertible into ethanol by mono-culture and co-culture of yeast strain. Cassava stalks 1.5% （w/v） in 0.1 M sulfuric acid was pretreated for 30 min at 135 ℃ under the pressure of 15 lb/inch2. The pretreated cassava stalk suspensions were neutralized to pH 5.5 for saccharification process. The enzyme solution （a-amylase, amyloglucosidase, cellulase, xylanase and pectinase solubilized in buffer pH 5.0） was used for hydrolysis ofpretreated cassava stalk at 50 ℃ for 24 h. The hydrolyaste was supplemented with additional nutrients. The culture was incubated at 30 ℃. The pretreatment of the stalk with dilute-acid resulted sugar yield of 0.57 g/g dry matter from enzymatic hydrolysis, which was higher than dilute-alkaline-pretreated and distilled water-pretreated stalk. The sugar hydrolysate was bioconverted to ethanol with separate hydrolysis and fermentation （SHF） and simultaneous saccharification and fermentation （SSF）. The highest ethanol yields of 98.43% and 95.29% were obtained in SHF and SSF, respectively by S. cerevisiae KM1195. The fermentation time of SSF process was 24-32 h shorter than that of the SHF （= 56 h）, but not significantly leading to difference in ethanol production （5.42 g/L-6.22 g/L for SSF; 5.9 g/L-6.23 g/L for SHF）.
文摘Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitumoral, antimicrobial and immunological properties. The aim of this work was to produce and to evaluate the biological properties of protein-bound polysaccharide complexes, extra intracellular （E-PPS and I-PPS）, extracted from P. ostreatus cultures, using agricultural sunflower wastes as carbon source. Three main compounds in the E-PPS and four main compounds in the I-PPS were identified by SEC-UV-RI-HPLC. These complexes of P. ostreatus present no toxicity in Artemia salina cultures, after 24 h of incubation. Antioxidant properties of the complexes were evaluated by radical scavenging activity using DPPH method and lipid peroxidation inhibition capacity, determined by erytbsocytes hemolysis. Additionally, E-PPS and I-PPS extracts revealed capacity to mimetize superoxide dismutase and catalase enzymatic activities. The hepatoprotector effect of E-PPS extracts in Wistar rats was evaluated by AST, ALT, ALP and y-GT activities, showing capacity to reduce the liver damage induced by ethanol-administration. This hepatoprotective effect is equivalent to that observed by silymarin, a standard drug. Our results suggests that the extracts of E-PPS and I-PPS produced by P. ostreatus cultures, using agricultural sunflower wastes as main carbon source, can be used as an important source of bioactive compounds with potential medicinal value.
文摘Cherry cultivar Misri （Bigarreau Noir Grossa） was used for making candy. Pitting of fruit was done manually and KMS （0.2%） was added for bleaching. The fruit was pretreated using 4 levels of CaCl2 （Co = 0%, C1 = 1%, C2 = 1.5%, C3 = 2%） and stored in jars for 4 weeks. Thereafter, application of colour was done using Erythrosine （0.05%） followed by dipping pitted fruits in sugar syrup for 24 hours. The samples were treated with 4 levels of citric acid （To = 0%, Tl = 1%, T2 = 1.5%, T3 = 2%） and then concentrated subsequently till desired TSS of 70~ Brix was attained. The samples were dried in cabinet drier at 80 ±20 ℃till constant moisture was attained. The product was packed in polyethene pouches and stored under ambient storage conditions. Results revealed that there was gradual increase in reducing sugars （%）, total sugars （%） during storage while as moisture content （%） decreased. The product developed was found economically profitable and viable for commercial production.
文摘Sugarcane shoots and leaves consist of 35.2% cellulose, 23.43% hemicellulose, 12.6% lignin and 6.59% ash on dry solid （DS） basis and have the potential to serve as low cost feedstocks for ethanol production. To improve the enzymatic digestibility of these biomass and bioethanol production, three pretreatment methods had been investigated and compared, including： （1） 2% w/v NaOH solution autoclaving pretreatment; （2） 2% w/v H2SO4 solution autoclaving pretreatment and （3） two steps of 2% w/v NaOH solution autoclaving followed by 2% w/v H2SO4 solution autoclaving pretreatment. Among them, the best result for ethanol production was obtained when 15 g DS of sugarcane shoots and leaves was pretreated by using two step of 2% w/v NaOH solution autoclaving followed by 2% w/v H2SO4 solution autoclaving. The highest ethanol concentration 30.40 g/L （92.65% in fermentation efficiency） was obtained from reducing sugar 89.25 g/L at 48 h. Moreover, the washing step of solid residue after pretreatment could reduce furfural and hydroxymethylfurfural （HMF） in all pretreatment methods when compared to unwashing solid residue after pretreatment.
基金Supported by National Natural Fund Program(31071636)Anhui Science and Technology Bureau Program(1206C0805017/KJ2010A262)
文摘[ Objective] The aim was to improve the saccharification of wheat bran cellulose. [ Method] Taking the wheat bran as raw materials, and using orthogonal method, the effects of acid concentration, temperature, times and substrate concentration on the saccharification were investigated. [ Result] The influence of temperature on the acid treatment of the sacchadfication of wheat bran cellulose was significant. Influences of acid concentration on the hydrolysis were distinct. Influences of time and substrate concentration were insignificant. The optimal pretreatment conditions were 1.5% of sulfuric acid concentration and 0. 067 g/ml of substrate concentration at 100℃ in three hours. Under this condition, the sugar concentration was 38.137 mg/ml, and the hydrolysis rate reached 51.485%. [ Conclusion] The study improved the saccharification of wheat bran cellulose, which provided theoretical basis for the application of wheat bran industrial process.
文摘L-（＋）-lactic acid production was studied by immobilized Lactobacillus rhamnosus TISTR108 on crude pectin from Krung Kha Mao （Cissampelospareira L.） leaves. Central composite design was employed to determine the maximum lactic acid production of 45.40 g/L in predicted model （Y = 43.98 - 2.43X1 ＋ 1.02X2 ＋ 2.96X3 - 8.72X1^2 - 3.99X2^2 - 1.74X3^2） with the factors at 5.9 of cultural medium pH, 37.6 ℃ of process temperature and 202 rpm of liquid agitation. Statistical analyses demonstrated very high significance for the regression model fitted the data adequately and explained the lactic acid production, since the F-value computed 54.89 was much higher than the tabulated F-value 2.08 for the lactic acid production at 5% level for linear and quadratic polynomial regression models. The highest experimental lactic acid production was 46.91 g/L at 72 h of fermentation.
基金Supported by the Foundation for Science and Technology (FCT) of Portugal (Nos. PTDC/AGR-AAM/66004/2006,SFRH/BD/ 60363/2009 and SFRH/BD/69185/2010)
文摘Soil salinization and non-point source pollution are among the most important and widespread environmental problems in European Mediterranean regions. Sweet sorghum （Sorghum bicolor （L.） Moench var. saccharatum） is a moderate to high salinity tolerant crop with low water and nutrient needs, seen as an alternative to grow in the water scarce regions. A three-year multifactorial study was conducted in southern Portugal to evaluate the combined effects of saline water and nitrogen application on the dry biomass （total, stems, and leaves）, sugar content （total reducing sugars and sucrose eontents） and sugar yield （here defined as the product of total reducing sugars and stems dry biomass） functions of sweet sorghum. Sorghum dry biomass and sugar yield showed diminishing returns for each incremental change of nitrogen. The use of saline irrigation waters also led to yield reduction. Exception was sucrose content which increased with increasing levels of sodium in the soil. Nitrogen need decreased as the amount of sodium applied increased. Stem dry biomass, sucrose content, and sugar yield progressively increased with progress in the experiment. The effect could be attributed to the increase of the amount of irrigation applied throughout the years, thus increasing the leaching fraction which promoted salt leaching from the root zone, reduced the salinity stress, increased plant transpiration, nitrogen uptake and biomass yield.
基金supported by the National Natural Science Foundation of China(21325208,21172209,21272050,21402181,21572212)Chinese Academy of Science(KJCX2-EW-J02,YZ201563)+5 种基金the Major/Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology(2014FXCX006)China Postdoctoral Science Foundation(2014M561835)the Specialized Research Fund for the Doctoral Program of Higher Education(20123402130008)Fundamental Research Funds for the Central Universities(WK2060190025,WK2060190033,WK2060190040,WK6030000023)the Key Technologies R&D Programme of Anhui Province(1604a0702027)Program for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of China
文摘Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.
