为探究椰壳颗粒活性炭活化过硫酸钠(PS)预处理对高固污泥厌氧发酵水解产酸性能的影响,通过调节挥发性脂肪酸(VFAs)产量、溶解性化学需氧量(SCOD)、溶解性蛋白质及多糖等指标,探究了不同剂量颗粒活性炭(GAC)与PS预处理对高固污泥产酸发...为探究椰壳颗粒活性炭活化过硫酸钠(PS)预处理对高固污泥厌氧发酵水解产酸性能的影响,通过调节挥发性脂肪酸(VFAs)产量、溶解性化学需氧量(SCOD)、溶解性蛋白质及多糖等指标,探究了不同剂量颗粒活性炭(GAC)与PS预处理对高固污泥产酸发酵的最佳条件。结果表明,当PS和GAC投加量分别为1.50 mmol·g^(-1)(以总固体计)和0.65 g g^(-1)(以总固体计)时,在发酵前期产酸速率相比于对照组提高了341.43%,后续发酵过程中,VFAs最大产量相比于对照组提高了28.43%。其中,乙酸作为优质碳源,其质量浓度增加了48.98%;继续增加GAC剂量时,反应器厌氧发酵性能下降,其原因可能是过量GAC会消耗已生成的SO_(4)^(-)·,降低污泥水解作用,同时GAC表面对VFAs的吸附也导致产酸量下降。三维荧光分析表明,在产酸量较高的反应器中,氨基酸、芳香族蛋白质等溶解性有机物的质量浓度较低,这说明适量椰壳颗粒活性炭活化PS预处理方式可提高高固厌氧发酵中微生物对于水解底物的利用率,从而提高污泥的厌氧产酸性能。本研究结果可为炭活化PS预处理技术在高固污泥厌氧消化中的应用提供参考。展开更多
[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam expl...[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam explosion and dilute acid hydrolysis as experimental materials,we measured and analyzed the effects of different treatments and particle size of maize stalk were analyzed. [Result] The optimal fermentative biohydrogen production was found under following parameters：pretreatment of 0.8% dilute H2SO4 following steam explosion,particle size of maize stalk of 0.425-0.850 mm,liquid-solid ratio [0.8% H2SO4 （M）：stalk （W）] of 10：1. [Conclusion] Post steam explosion,dilute 0.8% dilute H2SO4 intensified hydrolysis on maize stalk could produce fermentative biohydrogen production capacity.展开更多
Whey protein concentrate (WPC 80) and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis (DH). WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and e...Whey protein concentrate (WPC 80) and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis (DH). WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and evaluated for their nutritional qualities. Their chemical composition, protein solubility, amino acid composition, essential amino acid index (EAA index), biological value (BV), nutritional index (NI), chemical score, enzymic protein efficiency ratio (E-PER) and in vitro protein digestibility (IVPD) were determined. The results indicated that the enzymatic hydrolysis of WPC 80 and sodium caseinate by Protamex improved the solubility and IVPD of their hydrolysates. WPC 80, sodium caseinate and their hydrolysates were high-quality proteins and had a surplus of essential amino acids compared with the FAO/WHO/UNU (1985) reference standard. The nutritive value of WPC 80 and its hydrolysates was superior to that of sodium caseinate and its hydrolysates as indicated by some nutritional parameters such as the amino acid composition, chemical score, EAA index and predicted BV. However, the E-PER was lower for the WPC hydrolysates as compared to unhydrolyzed WPC 80 but sodium caseinate and its hydrolysates did not differ significantly. The nutritional qualities of WPC 80, sodium caseinate and their hydrolysates were good and make them appropriate for food formulations or as nutritional supplements.展开更多
The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abund...The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abundantly available worldwide, remains under development. The aim of this study was to evaluate the possibility of using the Musa cavendischii banana tree pseudostem as a substrate for alcoholic fermentation. Hydrolisis methods using dilute sulfuric acid （1% and 2% H2SO4; 15 and 30 min; 90 ℃, 100 ℃ and 120 ℃） and enzymes （pH 5.5; and 45 ℃ for 24 h reaction time） were evaluated both separately and in combination. The effect of chemical pre-treatment of the substrate using 1% and 3% m/m NaOH （120 ℃, 15 min） was verified for both methods. The highest yield coefficient of fermentable sugars from dry biomass （Yrs = 74%） was obtained using enzymatic hydrolysis and pre-treatment with 3% NaOH. Using acid hydrolysis, the maximum yield obtained was 22% （1% H2SO4, 120 ℃, 30 min）. Fermentation of the hydrolysates was satisfactory, and the maximum yield of ethanol formed per unit of substrate consumed, total productivity and efficiency values were 0.35 g, 0.90 g ethanol L^-1·h^-1 and 65.9%, respectively. This demonstrates the utility of banana tree pseudostems in second-generation ethanol production.展开更多
An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentat...An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.展开更多
A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good bio...A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.展开更多
Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented ...Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented to ethanol. Separated hydrolysis and fermentation （SHF） studies were carried out to produce ethanol from water hyacinth leaves. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions. The optimum pretreatment conditions included T = 135 ℃, t = 30 min, and sulfuric acid concentration = 0.1 M. The residue was enzymatically hydrolyzed using the mixture of enzymes cellulase, xylanase and pectinase. The maximum enzymatic saccharification of cellulosic material （76.8%） was achieved. SHF by mono-culture of Saccharomyces cerevisiae KM1195 achieved the highest yields of ethanol. Furthermore, ethanol production was accomplished with the co-culture ofS. cerevisiae TISTR5048 and Candida tropicalis TISTR5045 which produced the highest increase in ethanol Yield. In this case, the ethanol concentration of 3.42 （g/L）, percentage of the theoretical ethanol yield of 99.9%, the ethanol yield of 0.27 g/g and the productivity of 0.22 g/L/h were obtained. This suggested that mild acid pretreatment and co-cultureare promising methods to improve enzymatic hydrolysis and ethanol production from water hyacinth.展开更多
The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanol wastewater. Test ...The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanol wastewater. Test results show that TSTP process is quick start-up in 51 d, and the maximum VFA of hydrolytic acidification reactor effluent reaches 876 mg/L. Under the condition of volume loading of 6.56 kgCOD/m3·d, COD removal rate of the first-order EC reactor is about 85%, and under the condition of volume loading of 1.02 kgCOD/m3·d, COD removal rate of the second-order EC reactor is about 50%. When the inflow COD of TSTP process is between 7000-11000 mg/L, its effluent COD is lower than 600 mg/L. In the biological conversion process of methanol into methane,the production of acetic acids as an intermediate product can be ignored and the direct production of methane from methanol is predominant.展开更多
文摘为探究椰壳颗粒活性炭活化过硫酸钠(PS)预处理对高固污泥厌氧发酵水解产酸性能的影响,通过调节挥发性脂肪酸(VFAs)产量、溶解性化学需氧量(SCOD)、溶解性蛋白质及多糖等指标,探究了不同剂量颗粒活性炭(GAC)与PS预处理对高固污泥产酸发酵的最佳条件。结果表明,当PS和GAC投加量分别为1.50 mmol·g^(-1)(以总固体计)和0.65 g g^(-1)(以总固体计)时,在发酵前期产酸速率相比于对照组提高了341.43%,后续发酵过程中,VFAs最大产量相比于对照组提高了28.43%。其中,乙酸作为优质碳源,其质量浓度增加了48.98%;继续增加GAC剂量时,反应器厌氧发酵性能下降,其原因可能是过量GAC会消耗已生成的SO_(4)^(-)·,降低污泥水解作用,同时GAC表面对VFAs的吸附也导致产酸量下降。三维荧光分析表明,在产酸量较高的反应器中,氨基酸、芳香族蛋白质等溶解性有机物的质量浓度较低,这说明适量椰壳颗粒活性炭活化PS预处理方式可提高高固厌氧发酵中微生物对于水解底物的利用率,从而提高污泥的厌氧产酸性能。本研究结果可为炭活化PS预处理技术在高固污泥厌氧消化中的应用提供参考。
基金Supported by National Basic Research Program of China(2006CB708407 2009CB220005)+2 种基金National Natural Science Foun-dation of China (90610001 20871106)Program of 211 Projectfor Zhengzhou University from Ministry of Education~~
文摘[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam explosion and dilute acid hydrolysis as experimental materials,we measured and analyzed the effects of different treatments and particle size of maize stalk were analyzed. [Result] The optimal fermentative biohydrogen production was found under following parameters：pretreatment of 0.8% dilute H2SO4 following steam explosion,particle size of maize stalk of 0.425-0.850 mm,liquid-solid ratio [0.8% H2SO4 （M）：stalk （W）] of 10：1. [Conclusion] Post steam explosion,dilute 0.8% dilute H2SO4 intensified hydrolysis on maize stalk could produce fermentative biohydrogen production capacity.
文摘Whey protein concentrate (WPC 80) and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis (DH). WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and evaluated for their nutritional qualities. Their chemical composition, protein solubility, amino acid composition, essential amino acid index (EAA index), biological value (BV), nutritional index (NI), chemical score, enzymic protein efficiency ratio (E-PER) and in vitro protein digestibility (IVPD) were determined. The results indicated that the enzymatic hydrolysis of WPC 80 and sodium caseinate by Protamex improved the solubility and IVPD of their hydrolysates. WPC 80, sodium caseinate and their hydrolysates were high-quality proteins and had a surplus of essential amino acids compared with the FAO/WHO/UNU (1985) reference standard. The nutritive value of WPC 80 and its hydrolysates was superior to that of sodium caseinate and its hydrolysates as indicated by some nutritional parameters such as the amino acid composition, chemical score, EAA index and predicted BV. However, the E-PER was lower for the WPC hydrolysates as compared to unhydrolyzed WPC 80 but sodium caseinate and its hydrolysates did not differ significantly. The nutritional qualities of WPC 80, sodium caseinate and their hydrolysates were good and make them appropriate for food formulations or as nutritional supplements.
文摘The alcoholic fermentation of substrates rich in free soluble sugars is well known and has been industrially developed. However, the production of second-generation ethanol from lignocellulosic biomass, which is abundantly available worldwide, remains under development. The aim of this study was to evaluate the possibility of using the Musa cavendischii banana tree pseudostem as a substrate for alcoholic fermentation. Hydrolisis methods using dilute sulfuric acid （1% and 2% H2SO4; 15 and 30 min; 90 ℃, 100 ℃ and 120 ℃） and enzymes （pH 5.5; and 45 ℃ for 24 h reaction time） were evaluated both separately and in combination. The effect of chemical pre-treatment of the substrate using 1% and 3% m/m NaOH （120 ℃, 15 min） was verified for both methods. The highest yield coefficient of fermentable sugars from dry biomass （Yrs = 74%） was obtained using enzymatic hydrolysis and pre-treatment with 3% NaOH. Using acid hydrolysis, the maximum yield obtained was 22% （1% H2SO4, 120 ℃, 30 min）. Fermentation of the hydrolysates was satisfactory, and the maximum yield of ethanol formed per unit of substrate consumed, total productivity and efficiency values were 0.35 g, 0.90 g ethanol L^-1·h^-1 and 65.9%, respectively. This demonstrates the utility of banana tree pseudostems in second-generation ethanol production.
基金the National Natural Science Foundatioo of China(No.30670566)the International S&T Cooperation Program of China(No.2006DFA33150)
文摘An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.
基金Shanghai Science and Technology Committee(No.042312045)Shanghai Post-doctor Fund
文摘A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.
文摘Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented to ethanol. Separated hydrolysis and fermentation （SHF） studies were carried out to produce ethanol from water hyacinth leaves. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions. The optimum pretreatment conditions included T = 135 ℃, t = 30 min, and sulfuric acid concentration = 0.1 M. The residue was enzymatically hydrolyzed using the mixture of enzymes cellulase, xylanase and pectinase. The maximum enzymatic saccharification of cellulosic material （76.8%） was achieved. SHF by mono-culture of Saccharomyces cerevisiae KM1195 achieved the highest yields of ethanol. Furthermore, ethanol production was accomplished with the co-culture ofS. cerevisiae TISTR5048 and Candida tropicalis TISTR5045 which produced the highest increase in ethanol Yield. In this case, the ethanol concentration of 3.42 （g/L）, percentage of the theoretical ethanol yield of 99.9%, the ethanol yield of 0.27 g/g and the productivity of 0.22 g/L/h were obtained. This suggested that mild acid pretreatment and co-cultureare promising methods to improve enzymatic hydrolysis and ethanol production from water hyacinth.
基金Sponsored by the National Hi-Tech Research and Development Program of China (Grant No.2003AA601090)Projects of Development Plan of the State Key Fundamental Research of China (Grant No.2004CB4185)
文摘The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanol wastewater. Test results show that TSTP process is quick start-up in 51 d, and the maximum VFA of hydrolytic acidification reactor effluent reaches 876 mg/L. Under the condition of volume loading of 6.56 kgCOD/m3·d, COD removal rate of the first-order EC reactor is about 85%, and under the condition of volume loading of 1.02 kgCOD/m3·d, COD removal rate of the second-order EC reactor is about 50%. When the inflow COD of TSTP process is between 7000-11000 mg/L, its effluent COD is lower than 600 mg/L. In the biological conversion process of methanol into methane,the production of acetic acids as an intermediate product can be ignored and the direct production of methane from methanol is predominant.
