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1.
Oil Palm Frond (OPF) is one of lignocellulosic biomass, which can be utilized as raw material for bioethanol production. Bioethanol is produced as alternative energy to substitute gasoline. There are four steps in bioethanol production from OPF, i.e pretreatement, saccharification, fermentation and purification process. In this study, optimization of saccharification and fermentation process for OPF was investigated. Two methods and the variations of enzyme concentration were carried out in the saccharification and fermentation process. Separate hydrolysis and fermentation process (SHF) and simultaneous saccharification and fermentation process (SSF) were conducted to produce ethanol optimally. Variations of enzyme concentration used in this process were 10, 20, 30 and 40 FPU/g substrate. The result shows that the highest ethanol concentration can be obtained in SSF process with 30 FPU/g substrate of enzyme concentration. The process produced 59.20 g/L ethanol (95.95% yield ethanol) at 96 h of SSF process. 相似文献
2.
Borden Jacob R. Lee Youn Y. Yoon Hyon-Hee 《Applied biochemistry and biotechnology》2000,84(1-9):963-970
Astrain of Clostridium thermoaceticum (ATCC 49707) was evaluated for its homoacetate potential. This thermophilic anaerobe best produces acetate from glucose at
pH 6.0 and 59°C with a yield of 83% of theoretical. Enzyme hydrolysis of two substrates, a-cellulose and a pulp mill sludge,
yielded 68% and 70% digestion, respectively. The optimum conditions for the simultaneous saccharification and fermentation
(SSF) were substrate dependent: 55°C, pH 6.0 for α-cellulose, and 55°C, pH 5.5 for the pulp mill sludge. In the SSF with α-cellulose,
the overall yield of acetate was strongly influenced by the enzyme loading. In a fed-batch operation of SSF with α-cellulose,
an overall acetic acid yield of 60 wt% was obtained. Among the factors limiting the yields were incomplete digestion by the
enzyme and the end-product inhibition. In the SSF of pulp mill sludge, inhibitors present in the sludge severely limited bacterial
action. A large accumulation of glucose developed over the entire process, changing the intended SSF operation into a separate
hydrolysis and fermentation operation. Despite a long lag phase of microbial growth, a terminal yield of 85% was obtained
with this substrate. 相似文献
3.
Kwang Il Kim Woo Kyung Kim Deok Ki Seo In Sang Yoo Eun Ki Kim Hyon Hee Yoon 《Applied biochemistry and biotechnology》2003,107(1-3):637-647
Conversion of food wastes into lactic acid by simultaneous saccharification and fermentation (SSF) was investigated. The process
involves saccharification of the starch component in food wastes by a commercial amylolytic enzyme preparation (a mixture
of amyloglucosidase, α-amylase, and protease) and fermentation by Lactobacillus delbrueckii. The highest observed overall yield of lactic acid in the SSF was 91% of theoretical. Lactic acid concentration as high as
80 g/L was attainable in 48 h of the SSF. The optimum operating conditions for the maximum productivity were found to be 42°C
and pH 6.0. Without supplementation of nitrogen-containing nutrients, the lactic acid yield in the SSF decreased to 60%: 27
g/L of lactic acid from 60 g/L of food waste. The overall performance of the SSF, however, was not significantly affected
by the elimination of mineral supplements. 相似文献
4.
Ethanol production from Jerusalem artichoke was studied using inulinase and Z.mobilis by simultaneous saccharification and fermentation (SSF) process. The SSF process showed higher ethanol yield and productivity
than the acid or enzymatic prehydrolyzed two-step process. The optimum temperature and inulinase concentration for SSF were
35°C and 0.25% (v/w, 4.4 units/g of sugar), respectively. In order to operate the SSF process in a continuous mode, inulinase
and Z.mobilis cells were coimmobilized in alginate beads, using chitin as a matrix for enzyme immobilization. The maximum ethanol productivity
of the continuous SSF process was 55.1 g/L/h, with 55% conversion yield. At the conversion yield of 90%, the productivity
was 32.7 g/L/h. The continuous SSF system could be operated stably over 2 wk with an ethanol concentration of 48.6 g/L (95%
of theoretical yield). 相似文献
5.
Vandenberghe LP Soccol CR Prado FC Pandey A 《Applied biochemistry and biotechnology》2004,118(1-3):293-303
Studies were conducted to evaluate citric acid production by solid-state fermentation (SSF) using cassava bagasse as substrate
employing a fungal culture of Aspergillus niger LPB 21 at laboratory and semipilot scale. Optimization of the process parameters temperature, pH, initial humidity, aeration,
and nutritive composition was conducted in flasks and column fermentors. The results showed that thermal treatment of cassava
bagasse enhanced fungal fermentation efficacy, resulting in 220 g of citric acid/kg of dry cassava bagasse with only treated
cassava bagasse as substrate. The results obtained from the factorial experimental design in a column bioreactor showed that
an aeration rate of 60 mL/min (3 mL/[g·min]) and 60% initial humidity were optimum, resulting in 265.7 g/kg of dry cassava
bagasse citric acid production. This was almost 1.6 times higher than the quantities produced under unoptimized conditions
(167.4 g of citric acid/kg of dry cassava bagasse). The defined parameters were transferred to semipilot scale, which showed
high promise for large-scale citric acid production by SSF with cassava bagasse. Respirometry assays were carried out in order
to follow indirectly the biomass evolution of the process. Citric acid production reached 220, 309, 263, and 269 g/kg of dry
cassava bagasse in Erlenmeyer flasks, column fermentors, a tray bioreactor, and a horizontal drum bioreactor, respectively. 相似文献
6.
Mishra A 《Applied biochemistry and biotechnology》2006,135(1):33-42
This article reports the production of high levels of l-asparaginase from a new isolate of Aspergillus niger in solid state fermentation (SSF) using agrowastes from three leguminous crops (bran of Cajanus cajan, Phaseolus mungo, and Glycine max). When used as the sole source for growth in SSF, bran of G. max showed maximum enzyme production followed by that of P. mungo and C. cajan. A 96-h fermentation time under aerobic condition with moisture content of 70%, 30 min of cooking time and 1205–1405 μ range
of particle size in SSF appeared optimal for enzyme production. Enzyme yield was maximum (40.9±3.35 U/g of dry substrate)
at pH 6.5 and temperature 30±2°C. The optimum temperature and pH for enzyme activity were 40°C and 6.5, respectively. The
study suggests that choosing an appropriate substrate when coupled with process level optimization improves enzyme production
markedly. Developing an asparaginase production process based on bran of G. max as a substrate in SSF is economically attractive as it is a cheap and readily available raw material in agriculture-based
countries. 相似文献
7.
Valeria F. Soares Leda R. Castilho Elba P. S. Bon Denise M. G. Freire 《Applied biochemistry and biotechnology》2005,121(1-3):311-319
A Bacillus subtilis isolate was shown to be able to produce extracellular protease in solid-state fermentations (SSF) using soy cake as culture
medium. A significant effect of inoculum concentration and physiological age on protease production was observed. Maximum
activities were obtained for inocula consisting of exponentially growing cells at inoculum concentrations in the range of
0.7–2.0 mg g−1. A comparative study on the influence of cultivation temperature and initial medium pH on protease production in SSF and
in submerged fermentation (SF) revealed that in SSF a broader pH range (5–10), but the same optimum temperature (37°C), is
obtained when compared to SF. A kinetic study showed that enzyme production is associated with bacterial growth and that enzyme
inactivation begins before biomass reaches a maximum level for both SF and SSF. Maximum protease activity and productivity
were 960 U g−1 and 15.4 U g−1 h−1 for SSF, and 12 U mL−1 and 1.3 U mL−1 h−1 for SF. When SSF protease activity was expressed by volume of enzyme extract, the enzyme level was 10-fold higher and the
enzyme productivity 45% higher than in SF. These results indicate that this bacterial strain shows a high biotechnological
potential for protease production in solid-state fermentation. 相似文献
8.
Sabato D’Auria Fernando Pellino Francesco La Cara Roberto Barone Mosè Rossi Roberto Nucci 《Applied biochemistry and biotechnology》1996,61(1-2):157-166
ASulfolobus solfataricus β-glycosidase expressed inSaccharomyces cerevisiae (Sβgly) was immobilized on chitosan activated with glutaraldehyde. The yield of immobilization was evaluated as 80%. Compared
to the free β-glycosidase, the immobilized enzyme showed a similar pH optimum (pH = 7.0), the same increasing activity up
to 80°C, improved thermostability, and no inhibition by glucose. Functional studies pointed out that the kinetic constant
values for both enzymes were comparable. A bioreactor, assembled with the immobilized Sβgly, was used for glucose production.
The values of cellobiose conversion increased on increasing residence time in the bioreactor, following a nonlinear trend.
However, the highest glucose production/ min was obtained at a flow of 0.5 mL/min. 相似文献
9.
M. Hymavathi T. Sathish Ch. Subba Rao R. S. Prakasham 《Applied biochemistry and biotechnology》2009,159(1):191-198
L-asparaginase production was optimized using isolated Bacillus circulans (MTCC 8574) under solid-state fermentation (SSF) using locally available agricultural waste materials. Among different agricultural
materials (red gram husk, bengal gram husk, coconut, and groundnut cake), red gram husk gave the maximum enzyme production.
A wide range of SSF parameters were optimized for maximize the production of L-asparaginase. Preliminary studies revealed
that incubation temperature, moisture content, inoculum level, glucose, and L-asparagine play a vital role in enzyme yield.
The interactive behavior of each of these parameters along with their significance on enzyme yield was analyzed using fractional
factorial central composite design (FFCCD). The observed correlation coefficient (R
2) was 0.9714. Only L-asparagine and incubation temperature, were significant in linear and quadratic terms. L-asparaginase
yield improved from 780 to 2,322 U/gds which is more than 300% using FFCCD as a means of optimizing conditions. 相似文献
10.
Ballesteros Ignacio Oliva Jose Miguel Saez Felicia Ballesteros Mercedes 《Applied biochemistry and biotechnology》2001,91(1-9):237-252
The recent implementation of a new two-step centrifugation process for extracting olive oil in Spain has substantially reduced
water consumption, thereby eliminating oil mill wastewater. However, a new high sugar content residue is still generated.
In this work the two fractions present in the residue (olive pulp and fragm ented stones) were assayed as substrate for ethanol
production by the simultaneous saccharification and fermentation (SSF) process. Pretreatment of fragmented olive stones by
sulfuric acid-catalyzed steam explosion was the most effective treatment for increasing enzymatic digestibility; however,
a pretreatment step was not necessary to bioconvert the olive pulp into ethanol. Theolive pulp and fragmented olive stones
were tested by the SSF process using a fed-batch procedure. By adding the pulp three times at 24-h intervals, 76% of the theoretical
SSF yield was obtained. Experiments with fed-batch pretreated olive stones provided SSF yields significantly lower than those
obtained at standard SSF procedure. The preferred SSF conditions to obtain ethanol from olives stones (61% of theoretical
yield) were 10% substrate and addition of cellulases at 15 filter paper units/g of substrate. 相似文献
11.
Maria José Negro Paloma Manzanares Ignacio Ballesteros Jose Miguel Oliva Araceli Cabañas Mercedes Ballesteros 《Applied biochemistry and biotechnology》2003,105(1-3):87-100
Pretreatment has been recognized as a key step in enzyme-based conversion processes of lignocellulose biomass to ethanol. The aim of this study is to evaluate two hydrothermal pretreatments (steam explosion and liquid hot water) to enhance ethanol production from poplar (Populus nigra) biomass by a simultaneous saccharification and fermentation (SSF) process. The composition of liquid and solid fractions obtained after pretreatment, enzymatic digestibility, and ethanol production of poplar biomass pretreated at different experimental conditions was analyzed. The best results were obtained in steam explosion pretreatment at 210°C and 4 min, taking into account cellulose recovery above 95%, enzymatic hydrolysis yield of about 60%, SSF yield of 60% of theoretical, and 41% xylose recovery in the liquid fraction. Large particles can be used for poplar biomass in both pretreatments, since no significant effect of particle size on enzymatic hydrolysis and SSF was obtained. 相似文献
12.
Dutra JC da C Terzi S Bevilaqua JV Damaso MC Couri S Langone MA Senna LF 《Applied biochemistry and biotechnology》2008,147(1-3):63-75
The aim of this study was to monitor the biomass growth of Aspergillus niger in solid-state fermentation (SSF) for lipase production using digital image processing technique. The strain A. niger 11T53A14 was cultivated in SSF using wheat bran as support, which was enriched with 0.91% (m/v) of ammonium sulfate. The addition of several vegetable oils (castor, soybean, olive, corn, and palm oils) was investigated
to enhance lipase production. The maximum lipase activity was obtained using 2% (m/m) castor oil. In these conditions, the growth was evaluated each 24 h for 5 days by the glycosamine content analysis and digital
image processing. Lipase activity was also determined. The results indicated that the digital image process technique can
be used to monitor biomass growth in a SSF process and to correlate biomass growth and enzyme activity. In addition, the immobilized
esterification lipase activity was determined for the butyl oleate synthesis, with and without 50% v/v hexane, resulting in 650 and 120 U/g, respectively. The enzyme was also used for transesterification of soybean oil and ethanol
with maximum yield of 2.4%, after 30 min of reaction. 相似文献
13.
Among matrices used for immobilizing Bacillus acidicola cells [calcium alginate, chitosan + alginate, scotch brite, and polyurethane foam (PUF)], ??-amylase production was highest by PUF-immobilized cells (9.1?U?ml?1), which is higher than free cells (7.2?U?ml?1). The PUF-immobilized cells could be reused over seven cycles with sustained ??-amylase production. When three variables (moisture, starch, and ammonium sulfate), which significantly affected enzyme production in solid-state fermentation (SSF), were optimized using response surface methodology, 5.6-fold enhancement in enzyme production was attained. The enzyme production in SSF is 3.8-fold higher than that in submerged fermentation. The bread made by supplementing dough with ??-amylase of B. acidicola scored better than those with the xylanase of Bacillus halodurans and thermostable ??-amylase of Geobacillus thermoleovorans. 相似文献
14.
The major constraint in the enzymatic saccharification of biomass for ethanol production is the cost of cellulase enzymes.
Production cost of cellulases may be brought down by multifaceted approaches which includes the use of cheap lignocellulosic
substrates for fermentation production of the enzyme, and the use of cost efficient fermentation strategies like solid state
fermentation (SSF). The current study investigated the production of cellulase by Trichoderma reesei RUT C30 on wheat bran under SSF. Process parameters important in cellulase production were identified by a Plackett and Burman
design and the parameters with significant effects on enzyme production were optimized for maximal yield using a central composite
rotary design (CCD). Higher initial moisture content of the medium had a negative effect on production whereas incubation
temperature influenced cellulase production positively in the tested range. Optimization of the levels of incubation temperature
and initial moisture content of the medium resulted in a 6.2 fold increase in production from 0.605 to 3.8 U/gds of cellulase.
The optimal combination of moisture and temperature was found to be 37.56% and 30 °C, respectively, for maximal cellulase
production by the fungus on wheat bran. 相似文献
15.
Stéphanie Sutter France Thevenieau Anne Bourdillon Joëlle De Coninck 《Applied biochemistry and biotechnology》2017,182(3):910-924
Water extracts from solid-state fermentation (SSF) on rapeseed meal using filamentous fungi exhibit interesting immunomodulatory activities in vitro. Immunomodulation was determined by the capacity of the compounds to activate blood neutrophils and to influence cytokine production in human peripheral blood mononuclear cells (PBMC) and mouse bone marrow-derived macrophages (BMDM). Among the strains tested, Aspergillus sojae mycelium and SSF extracts were the most promising in terms of enhancing the immune response. The filamentous fungus was also successfully cultivated in a pre-pilot bioreactor with forced aeration. The results indicated that the extracts not only activated blood neutrophils but also significantly modulated IL-1β cytokine levels with lipopolysaccharide (LPS)-stimulated PBMC and BMDM without any cytotoxicity in immune cells. IL-1β was down-regulated in a dose-dependent manner in the presence of A. sojae crude mycelium and SSF extract with PBMC, which indicated that there was an anti-inflammatory activity, whereas IL-1β secretion was up-regulated in the presence of stimulated BMDM with the highest concentration that was tested (100 μg/mL). The non-fermented rapeseed had no effect at the same concentration. SSF culture, as a natural product, may be a good source for the development of functional feed with an immunostimulating effect or could potentially be used in medicinal applications. 相似文献
16.
Mark S. Ou Nazimuddin Mohammed L. O. Ingram K. T. Shanmugam 《Applied biochemistry and biotechnology》2009,155(1-3):76-82
Ethanol production from lignocellulosic biomass depends on simultaneous saccharification of cellulose to glucose by fungal cellulases and fermentation of glucose to ethanol by microbial biocatalysts (SSF). The cost of cellulase enzymes represents a significant challenge for the commercial conversion of lignocellulosic biomass into renewable chemicals such as ethanol and monomers for plastics. The cellulase concentration for optimum SSF of crystalline cellulose with fungal enzymes and a moderate thermophile, Bacillus coagulans, was determined to be about 7.5 FPU g?1 cellulose. This is about three times lower than the amount of cellulase required for SSF with Saccharomyces cerevisiae, Zymomonas mobilis, or Lactococcus lactis subsp. lactis whose growth and fermentation temperature optimum is significantly lower than that of the fungal cellulase activity. In addition, B. coagulans also converted about 80% of the theoretical yield of products from 40 g/L of crystalline cellulose in about 48 h of SSF with 10 FPU g?1 cellulose while yeast, during the same period, only produced about 50% of the highest yield produced at end of 7 days of SSF. These results show that a match in the temperature optima for cellulase activity and fermentation is essential for decreasing the cost of cellulase in cellulosic ethanol production. 相似文献
17.
Using the simultaneoussaccharification and fermentation (SSF) technique, pulp mill solid waste cellulose was converted into
glucose using cellulase enzyme and glucose into lacticacid using NRRL B445. SSF experiments were conducted at various pH levels,
temperatures, and nutrient concentrations, and the lactic acid yield ranged from 86 to 97%. The depletion of xylose in SSF
was further investigated by inoculating NRRL B445 into a xylose-only medium. On prolonged incubation, depletion of xylose
with lactic acid production was observed. An experimental procedure with a nonglucose medium was developed to eliminate the
lag phase. From xylose fermentation, Lactobacillus delbrueckii yielded 88–92% lactic acid and 2–12% acetic acid. 相似文献
18.
Nonisothermal simultaneous saccharification and fermentation for direct conversion of lignocellulosic biomass to ethanol 总被引:1,自引:0,他引:1
The enzymatic reaction in the simultaneous saccharification and fermentation (SSF) is operated at a temperature much lower
than its optimum level. This forces the enzyme activity to be far below its potential, consequently raising the enzyme requirement.
To alleviate this problem, a nonisothermal simultaneous saccharification and fermentation process (NSSF) was investigated.
The NSSF is devised so that saccharification and fermentation occur simultaneously, yet in two separate reactors that are
maintained at different temperatures. Lignocellulosic biomass is retained inside a column reactor and hydrolyzed at the optimum
temperature for the enzymatic reaction (50°C). The effluent from the column reactor is recirculated through a fermenter, which
runs at its optimum temperature (20-30°C). The cellulase enzyme activity is increased by a factor of 2-3 when the hydrolysis
temperature is raised from 30 to 50°C. The NSSF process has improved the enzymatic reaction in the SSF to the extent that
it reduces the overall enzyme requirement by 30-40%. The effect of temperature on β-glucosidase activity was the most significant
among the individual cellulase compounds. Both ethanol yield and productivity in the NSSF are substantially higher than those
in the SSF at the enzyme loading of 5 IFPU/g glucan. With 10 IFPU/g glucan, improvement in productivity was more discernible
for the NSSF. The terminal yield attainable in 4 d with the SSF was reachable in 40 h with the NSSF. 相似文献
19.
Solid-state fermentation of lignocellulosic plant residues from Brassica napus by Pleurotus ostreatus 总被引:3,自引:0,他引:3
Solid-state fermentation (SSF) of inedible parts of rapeseed was carried out using a white-rot fungus, Pleurotus ostreatus, to degrade lignocellulosic material for mycelial-single cell protein (SCP) production. This SSF system has the potential
to be adapted to a controlled ecological life support system in space travel owing to the lack of storage space. The system
for converting lignocellulosic material to SCP by P. ostreatus is simple; it can be carried out in a compact reactor. The fungal vegetative growth was better with a particle size of plant
material ranging from 0.42 to 10 mm, whereas lignin degradation of the lignocellulose was the highest with particle sizes
ranging from 0.42 to 0.84 mm. The addition of veratry alcohol (3,4-dimethoxybenzyl alcohol), hydrogen peroxide, and glycerol
promotes lignocellulose degradation by P. ostreatus. The enhancement of bioconversion was also observed when a gas-flow bioreactor was used to supply oxygen and to maintain
the constant moisture of the reactor. With this reactor, approx 85% of the material was converted to fungal and other types
of biomass after 60 d of incubation. 相似文献
20.
Paper mill sludge is a solid waste material composed of pulp residues and ash generated from pulping and paper making processes. The carbohydrate portion of the sludge has chemical and physical characteristics similar to pulp. Because of its high carbohydrate content and well-dispersed structure, the sludges can be biologically converted to value-added products without pretreatment. In this study, two different types of paper mill sludges, primary sludge and recycle sludge, were evaluated as a feedstock for bioconversion to ethanol. The sludges were first subjected to enzymatic conversion to sugars by commercial cellulase enzymes. The enzymatic conversion was inefficient because of interference by ash in the sludges with the enzymatic reaction. The main cause was that the pH level is dictated by CaCO3 in ash, which is two units higher than the pH optimum of cellulase. To alleviate this problem, simultaneous saccharification and cofermentation (SSCF) using cellulase (Spezyme CP) and recombinant Escherichia coli (ATCC-55124), and simultaneous saccharification and fermentation (SSF) using cellulase and Saccharomyces cerevisiae (ATCC-200062) were applied to the sludges without any pretreatment. Ethanol yields of 75–81% of the theoretical maximum were obtained from the SSCF on the basis of total carbohydrates. The yield from the SSF was also found to be in the range of 74–80% on the basis of glucan. The SSCF and SSF proceeded under stable condition with the pH staying near 5.0, close to the optimum for cellulase. Decrease of pH occurred due to carbonic acid and other organic acids formed during fermentation. The ash was partially neutralized by the acids produced from the SSCF and SSF and acted as a buffer to stabilize the pH during fermentation. When the SSF and SSCF were operated in fed-batch mode, the ethanol concentration in the broth increased from 25.5 and 32.6 g/L (single feed) to 45 and 42 g/L, respectively. The ethanol concentration was limited by the tolerance of the microorganism in the case of SSCF. The ethanol yield in fed-batch operation decreased to 68% for SSCF and 70% for SSF. The high-solids condition in the bioreactor appears to create adverse effects on the cellulase reaction. 相似文献