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1.
TheBacillus subtilis alkaline protease(aprA) gene was previously cloned on a pUBHO-derivative plasmid. High levels of expression and gene stability were demonstrated
whenB. subtilis cells were grown on the laboratory medium 2XSG.B. subtilis cells harboring the multicopyaprA gene were grown on basal medium, supplemented with 1 % chicken feather as a source of energy, carbon, and nitrogen. Proteolytic
and kera-tinolytic activities were monitored throughout the cultivation time. A high level of keratinolytic activity was obtained,
and this indicates that alkaline protease is acting as a keratinase. Furthermore, considerable amounts of soluble proteins
and free amino acids were obtained as a result of the enzymatic hydrolysis of feather. Biodegradation of feather waste using
these cells represents an alternative way to improve the nutritional value of feather, since feather waste is currently utilized
on a limited basis as a dietary protein supplement for animal feedstuffs. Moreover, the release of free amino acids from feather
and the secreted keratinase enzyme would promote industries based on feather waste. 相似文献
2.
Isolation,identification, and keratinolytic activity of several feather-degrading bacterial isolates
Several feather-degrading bacterial isolates were isolated from Egyptian soil. These isolates were able to degrade chicken
feather, when grown on basal medium containing 1% native feather as a source of energy, carbon, and nitrogen. Feather waste,
generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin, which is not easily
degradable by common proteolytic enzymes. The isolates were identified according to the morphological characteristics, biochemical
tests, and API 50 CHBBacillus system. Proteolytic and keratinolytic activities of these isolates were monitored throughout the cultivation of the bacterial
isolates on feather. Resulting soluble proteins, which were released as a result of the biodegradation of feather, were demonstrated
by SDS-PAGE. 相似文献
3.
A new type of reactor, the attrition bioreactor, has been developed to increase the rate of the enzymatic hydrolysis of cellulose
and also to cut pretreatment costs. It was found that the attrition bioreactor could be operated continuously or semicontinuously
in conjunction with a membrane filter to produce a high cellulose conversion rate and low enzyme consumption. The membrane
filter served to contain the enzyme and cellulose within the reactor while allowing sugar to permeate as a product. 相似文献
4.
Patricia M. G. Paiva Luana C. B. B. Coelho 《Applied biochemistry and biotechnology》1992,36(2):113-118
Two additional electrophoretically distinct molecular forms, isoforms (iso) 2 and 3, with lectin properties were isolated
fromCratylia mollis Mart, seeds (FABACEAE), by extraction with 0.15M NaCl and ammonium sulfate fractionation, followed by chromatography on Sephadex
G-75 and Bio-Gel P-200 (iso 2), as well as CM-Cellulose and Sephadex G-75 (iso 3). Both isoforms were human group nonspecific
and showed distinct specificity. Polyacrylamide gel electrophoresis resolved iso 2 and 3 in polypeptides of apparent mol wts
60 and 31 kDa, respectively; a distinct isoelectric focusing pattern was obtained for iso 2 and 3, under denaturing and reducing
conditions. 相似文献
5.
Owen S. Jeong B. C. Poole P. S. Macaskie L. E. 《Applied biochemistry and biotechnology》1992,(1):693-707
Tributyl phosphate (TBP), a plasticizer and solvent, is used in nuclear fuel reprocessing, generating TBP wastes laden with
residual uranium. ACitrobacter sp. accumulated heavy metals via a phosphohydrolase(s) that precipitated metals with inorganic phosphate liberated from an
organic phosphate “donor” molecule (TBP). Mutant analysis suggested that TBP hydrolysis was not attributable to a previously
documented acid phosphatase (monoesterase). Purified monoesterase had little activity against phospho di- and triesters, had
no requirement for Mg2+ or Mn2+, and was EDTA-resistant. Conversely, TBP cleavage by immobilized cells was enhanced by Mg2+, and ininhibited by Mn2+ and EDTA. A separate phosphotri/diesterase was implicated. 相似文献
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8.
Aspen wood substrates with varying degrees of deacetylation, xylan, and lignin removal have been prepared and submitted to
enzymatic hydrolysis with a cellulase/hemicellulase preparation for an extended constant period of hydrolysis. Controlled
deacetylation has been achieved by treating wood with various alkali metal hydroxide solutions, at various alkali/wood ratios.
It has been found that samples with the same extent of deacetylation produce the same sugar yields upon enzymatic hydrolysis.
Increased degree of deacetylation increases the yield of sugars obtained from enzymatic hydrolysis, all other compositional
parameters held constant. The acetyl group removal is proportional to the stoichiometric relation between added base and wood
acetyl content, i.e., the same number of milliequivalents of base/weight of wood remove the same extent of acetyl groups,
regardless of the concentration of the base solution. No cation effects are found among Li, Na, and K alkali hydroxide solutions,
suggesting that swelling is not as important a parameter as is the removal of the acetyl groups from the xylan backbone in
determining the extent of hydrolyzability of the resulting sample. 相似文献
9.
Based on this preliminary study, a metric ton of dry southern red oak chips subjected to a first-stage dilute sulfuric acid
hydrolysis would yield 132 kg of xylose and 40 kg of glucose and mannose. A second-stage dilute sulfuric acid hydrolysis on
the first-stage residue would yield only 128 kg of additional glucose, but a second-stage cellulytic enzyme hydrolysis on
the first-stage residue would yield an additional 265 kg of glucose. Fermentation of these hydrolyzates would show that the
hybrid process would yield over 50% more ethanol. Results on other biomass are also included. 相似文献
10.
Growth inhibition in animal cell culture 总被引:6,自引:0,他引:6
Eight independent cell lines accumulated ammonia in culture to concentrations between 1.3 and 2.9 mM. The growth inhibition of such concentrations of ammonium chloride when added to culture medium was variable. The cell lines tested could be divided into 3 groups depending on their growth response to 2 mM added NH4Cl. In the first group (293, HDF, Vero, and PQXB1/2) little (less than 14%) or no growth inhibition occurred. In the second group (McCoy and MDCK) a reduction in final cell yield of 50-60% was observed. The third group (HeLa and BHK) was most sensitive to the effects of NH4Cl with growth inhibition (greater than 75%) compared to controls. The growth inhibitory effect of added lactate up to 20 mM was negligible (less than 10%) for 3 cell lines, although one cell line (PQXB1/2) showed greater sensitivity. The interactive effects of ammonia and lactate were determined in a matrix experiment. At lactate (greater than 12 mM) and ammonia (1-4 mM), the growth inhibitory effects of the two components were synergistic. However, at low concentrations of lactate (less than 12 mM) the toxic effect of ammonia was reduced. A proposed mechanism for the sparing effect of lactate on ammonia toxicity is discussed. This may have importance in developing strategies for the optimal growth of ammonia-sensitive cell lines. 相似文献
11.
Streptomyces setonii 75Vi2 produces an extracellular coal-solubilizing component(s) in the absence of coal. The heat stability, relatively low
molecular weight, and insensitivity to proteases of the substance(s) responsible for coal solubilization indicate that the
process is nonenzymatic. This report describes factors affecting the production and activity of this substance(s) and the
similarity in its action to alkaline buffer solutions in solubilizing coal. 相似文献
12.
Matsunaga Tadashi Takeyama Haruko Sudo Hiroaki Oyama Nobuo Ariura Shunsuke Takano Hiroyuki Hirano Morio Burgess J. Grant Sode Koji Nakamura Noriyuki 《Applied biochemistry and biotechnology》1991,(1):157-167
A photobioreactor was constructed in the form of a Perspex column 900 mm tall with an internal diameter of 70 mm. The reactor
volume was 1.8 L and the light source consisted of a metal-halide lamp to reproduce sunlight. Light was distributed through
the culture using a new type of optical fiber that diffuses light out through its surface, perpendicular to the fiber axis.
A cluster of 661 light-diffusing optical fibers (LDOFs) pass from the light source through the reactor column (60-cm culture
depth) and are connected to a mirror at the top of the reactor. This biosolar reactor has been used for the production of
glutamate from CO2 by the marine cyanobacterium Synechococcus sp. NKBG040607. We present here details of the construction of the biosolar reactor
and characterization of its properties. The effect of light intensity on glutamate production was measured. Carbon dioxide-to-glutamate
conversion ratios were determined at different cell densities: the maximum conversion ratio (28%) was achieved at a cell density
of 3x108 cells/mL. A comparison of glutamate production using the LDOF biosolar reactor described here with production by batch culture
using free or immobilized cells showed that use of an optical-fiber biosolar reactor increased glutamate-production efficiency
6.75-fold. We conclude that as a result of its high surface-to-volume ratio (692/m) increased photoproduction of useful compounds
may be achieved. Such a system is generally applicable to all aspects of photobiotechnology. 相似文献
13.
Hiroshi Ooshima Masahiro Kurakake Jyoji Kato Yoshio Harano 《Applied biochemistry and biotechnology》1991,31(3):253-266
Hydrolysis of pure cellulose Avicel has been carried out, using Meicelase from Trichoderma viride, where the enzymatic activity of cellulase adsorbed on cellulose and its changes during the hydrolysis were investigated. A rapid drop of the hydrolysis rate during the reaction, that is always observed in enzymatic hydrolysis of cellulose, could be explained by a decline of specific activity of adsorbed enzyme, and it was implied that the decline results from a loss of synergistic action between endoglucanase and exoglucanase. An empirical equation expresses the change of hydrolysis rate during the reaction and also shows that the change of the hydrolysis rate is caused by the decline of the specific enzymatic activity of adsorbed enzyme. 相似文献
14.
Chetsumon Aparat Umeda Fusako Maeda Isamu Yagi Kiyohito Mizoguchi Tadashi Miura Yoshiharu 《Applied biochemistry and biotechnology》1998,(1):249-256
A photobioreactor was constructed using anchored polyurethane foam strips (1 x 1 x 40 cm) fixed onto a stainless-steel ring
to prevent flotation, as a biomass support material (BSM). This type of reactor was named a seaweed-type bioreactor. A filamentous
cyanobacterium, Scytonema sp. TISTR 8208, which produces a novel cyclic dodecapeptide antibiotic, was immobilized in seaweed-type
photobioreactor and cultivated with air containing 5% CO2 sparged at a gas flow rate of 250 mL/min under illumination at a light intensity of 200 μmol photon m-2s-1. The antibiotic produced in the seaweed-type photobioreactor was purified by HPLC and examined regarding its spectrum and
mode of action. The antibiotic effectively inhibited the growth of Gram-positive bacteria, pathogenic yeasts, and filamentous
fungi, but it had only a weak effect on Gram-negative bacteria. Scanning electron micrograph analysis showed that the most
characteristic change was swelling of the cells after exposure to the antibiotic. The antibiotic seems to alter the conformation
of the microbial cell membrane, thereby changing its permeability, leading to osmotic shock. 相似文献
15.
Partially purified S1 nuclease was bound through its carbohydrate moiety to Con A-Sepharose containing increasing amounts of lectin. The retention of activity was high, varying essentially from 75% on the "low lectin" matrix (1 mg Con A/mL of Sepharose), to no detectable activity on the "high lectin" matrix (8 mg Con A/mL of Sepharose). However, approximately 50% activity could be restored in "high lectin" matrix when the coupling was carried out in the presence of glucose, suggesting that the loss of activity on the "high lectin" matrix is caused by conformational changes brought about by the multiple attachment of the enzyme to the matrix. Interaction of Con A with S1 nuclease was used to predict the nature of carbohydrate moiety and its location with respect to the active site of the enzyme. Immobilization resulted in an increase in the optimum temperature, pH, and temperature stabilities, but it did not affect the pH optimum. A marginal increase in the apparent Km was observed. The bound enzyme also showed enhanced stability toward 8 M urea. On repeated use, the bound enzyme retained more than 80% of its initial activity after 6 cycles. These results are discussed taking into consideration the factors affecting immobilized enzymes. In addition, the potential use of immobilized S1 nuclease as an analytical tool is discussed. 相似文献
16.
John D. Wright Charles E. Wyman Karel Grohmann 《Applied biochemistry and biotechnology》1988,18(1):75-90
Simultaneous saccharification and fermentation (SSF) processes for producing ethanol from lignocellulose are capable of improved
hydrolysis rates, yields, and product concentrations compared to separate hydrolysis and fermentation (SHF) systems, because
the continuous removal of the sugars by the yeasts reduces the end-product inhibition of the enzyme complex. Recent experiments
using Genencor 150L cellulase and mixed yeast cultures have produced yields and concentrations of ethanol from cellulose of
80% and 4.5%, respectively. The mixed culture was employed because B.clausenii has the ability to ferment cellobiose (further reducing end-product inhibition), while the brewing yeastS. cerevisiae provides a robust ability to ferment the monomeric sugars. These experimental results are combined with a process model to
evaluate the economics of the process and to investigate the effect of alternative processes, conditions, and organisms. 相似文献
17.
Mohagheghi Ali Evans Kent Finkelstein Mark Zhang Min 《Applied biochemistry and biotechnology》1998,(1):285-299
Cofermentation of xylose and arabinose, in addition to glucose, is critical for complete bioconversion of lignocellulosic
biomass, such as agricultural residues and herbaceous energy crops, to ethanol. A factorial design experiment was used to
evaluate the cofermentation of glucose, xylose, and arabinose with mixed cultures of two genetically engineeredZymomonas mobilis strains (one ferments xylose and the other arabinose). The pH range studied was 5.0-6.0, and the temperature range was 30-37°C
The individual sugar concentrations used were 30 g/L glucose, 30 g/L xylose, and 20 g/L arabinose. The optimal cofermentation
conditions obtained by data analysis, using Design Expert software, were pH 5.85 and temperature 31.5°C. The cofermentation
process yield at optimal conditions was 72.5% of theoritical maximum. The results showed that neither the arabinose strain
nor arabinose affected the performance of the xylose strain; however, both xylose strain and xylose had a significant effect
on the performance of the arabinose strain. Although cofermentation of all three sugars is achieved by the mixed cultures,
there is a preferential order of sugar utilization. Glucose is used rapidly, then xylose, followed by arabinose. 相似文献
18.
Applied Biochemistry and Biotechnology - 相似文献
19.
This article presents the advanced technology that has been developed by BioEnergy International of Gainesville, Florida,
utilizing novel recombinant strains of bacteria developed by Lonnie Ingram of the University of Florida. The first commercial
applications of these unique fermenting organisms convert 5-carbon sugars, as well as 6-carbon sugars, and oligomers of cellulose
(e.g., cellobiose and cellotriose) directly to ethanol. The proposed systems that will be utilized for conversion of agricultural
wastes, mixed waste papers, and pulp and paper mill waste in forthcoming commercial installations are now under design. This
involves the extensive experience of Raphael Katzen Associates International, Inc. in acid hydrolysis, enzyme production,
enzymatic hydrolysis, large-scale fermentation engineering, and distillation/dehydration.
Specific examples of this advanced technology will be presented in different applications, namely:
相似文献
1. | Conversion of the hemicellulose content of sugar cane bagasse to 5-carbon sugars by mild-acid prehydrolysis, followed by fermentation of the 5-carbon sugar extract with recombinantEscherichia coli in a commercial installation soon to be under construction in Brazil. This unique process utilizes the surplus hemicellulose fraction of bagasse not required for steam and power generation to produce ethanol, additional to that from the original cane juice, which has been converted by conventional sucrose fermentation to ethanol. The process also recovers and converts to ethanol the majority of sucrose normally lost with the bagasse fibers. Resultant beer is enriched in an innovative process to eliminate the need for incremental rectification capacity. |
2. | Application of this technology to mixed waste paper in Florida, with a moderate loading of newsprint (85% mechanical wood fiber), will involve a mild-acid prehydrolysis, the partial extraction of the 5-carbon sugars produced from hemicellulose as a feedstock for propagation of the recombinantKlebsiella oxytoca bacterium. Included is a facility providing for in-house production of cellulase enzyme, as an active whole broth for direct use in simultaneous saccharification and fermentation (SSF) of the remaining cellulose and residual 5-carbon sugars to ethanol. This is followed by distillation and dehydration in the advanced commercially available low-energy recovery system. |
3. | Another potential application of this unique technology involves utilization of a variety of wastes from several pulp and paper mills in close proximity, permitting collection of these wastes at low cost and reducing the considerable cost encountered in disposing of such low-energy wet waste. Based on pilot plant experiences with converting such waste by simultaneous enzymatic hydrolysis and fermentation, the same techniques will be applied as in the second case, with use of acid prehydrolysis only if the hemicellulose-derived sugars can be economically recovered. If not, acid hydrolysis will be eliminated and only the simultaneous saccharification and fermentation will be carried out, utilizing in-house-produced enzyme broth and recombinantKlebsiella oxytoca. |
20.
Goldstein Irving S. Bayat-Makooi Fred Sabharwal H. S. Singh T. M. 《Applied biochemistry and biotechnology》1989,(1):95-106
Satisfactory separation of either hydrochloric or sulfuric acid from sugars in wood hydrolyzates by application of membrane
technology is technically feasible. The permeability of disaccharides is less than 1% that of the acids. Acid flux in diffusion
dialysis is only 6% of acid flux at optimum current density in electrodialysis. Critical parameters for economic feasibility
are acid to wood ratio in hydrolysis, current efficiency, and membrane service life. Best case estimates project total costs
for sulfuric acid recovery and loss of about $0.02 per pound of glucose produced. 相似文献