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1.
V. R. Linardi C. M. M. C. Andrade M. M. Figueira M. C. Andrade A. A. V. Souza 《Folia microbiologica》1993,38(4):281-284
Some physical and chemical properties ofα-amylase (EC 3.2.1.1) and glucoamylase (EC 3.2.1.3) produced in semisolid fermentation byCandida fennica FTPT-1829,C. famata FTPT-1539 andC. fennica FTPT-8903 were determined. The optimum temperature values were 42, 44, 48 °C and 60, 50, 50 °C forα-amylase and glucoamylase excreted byC. fennica 8903,C. fennica 1829 andC. famata 1539, respectively. The optimum pH values for all strains were 5.0 and 6.0 forα-amylase and glucoamylase, respectively. The degradation of pullulan by all the yeast species indicates debranching activity.
This research was carried out with financial support fromPrPq/UFMG. The second author received grants fromRHAE/CNPq. 相似文献
2.
A chromogenic substrate (Cibachron blue-amylose), and soluble starch and maltose were used to characterize the amylolytic system from Schwanniomyces castellii 3754. The strain was able to produce inducible -amylase (EC 3.2.1.1) and glucoamylase (EC 3.2.1.3) when grown on different C sources. The effect of the C source was slightly different for -amylase and glucoamylase production. Melezitose, maltose and soluble starch enhanced both -amylase and glucoamylase synthesis to nearly the same extent; amylose, trehalose and cellobiose particularly induced -amylase synthesis. The optimal pH for the release of both amylases was 5.5–7.0; maximal -amylase synthesis, on the other hand, was observed in the medium buffered at pH 6.0. The optimal pH for -amylase and glucoamylase activity was in the range of 4.5–7.2 and 4.2–5.5, respectively. Temperatures allowing maximal activity were 45°C for -amylase and 45–52°C for glucoamylase; a rapid decline of both activities was observed just above these temperatures.The species Schwanniomyces castellii (together with Schw. alluvius) is now considered to be synonymous with Schw. occidentalis var. occidentalis (Kreger-Van Rij 1984). 相似文献
3.
Ashis K. Mukherjee Tadi Satish Kumar Sudhir K. Rai Jetendra K. Roy 《Biotechnology and Bioprocess Engineering》2010,15(6):984-992
We report the statistical optimization of the immobilization of alkaline α-amylase [E.C. 3.2.1.1] from Bacillus alcalophilus onto nano-sized supermagnetic ironoxide nanoparticles (MNPs) for augmenting the cost effective industrial application of
MNP-bound α-amylase. Both Plackett-Burman factorial design and response surface methodology (RSM) were employed to screen
the influence of different parameters and the central effect of response on the α-amylase-iron oxide MNP binding process.
The high coefficient of determination (R2) and analysis of variance (ANOVA) of the quadratic model indicated the competence
of the proposed model. The size of the MNPs was confirmed by X-ray diffraction and scanning electron microscope analyses in
which Fourier transform infrared spectroscopy suggested immobilization of the enzyme on iron-oxide MNPs. A significant improvement
(∼ 26-fold) in specific activity, thermal and storage stability, and reusability of α-amylase after binding with iron-oxide
MNP reinforced the improved biotechnological potential of the α-amylase iron-oxide MNP bioconjugate compared to free α-amylase.
These results open new avenues for applying this MNP immobilized enzyme in different industrial sectors, notably in the paper
and brewing industries. 相似文献
4.
J. L. Meers 《Antonie van Leeuwenhoek》1972,38(1):585-590
The production ofα-amylase (α-1,4 glucan-4-glucan hydrolase; E.C. 3.2.1.1.) by a strain ofBacillus licheniformis has been studied in batch and continuous cultures. The synthesis of this enzyme was shown to be repressed by glucose or other
low-molecular-weight metabolisable sugars. Consequently, amylase production in a medium which contained “liquified” starch
only began after the low-molecular-weight sugars had been dissimilated. Thereafter, the dextrins in the medium were degraded
by amylase produced by the bacteria to yield further quantities of metabolisable sugars. These sugars were continuously dissimilated
by the growing organisms and never accumulated to concentrations where they would repress further amylase synthesis. A clear
analogy could thus be drawn with bacteria growing in a carbon-limited environment in a chemostat. Therefore,α-amylase production byB. licheniformis organisms growing in 3-litre chemostats was studied. No evidence was obtained to infer that an inducer was necessary for
amylase production, and it was concluded that the prime factors influencing amylase production, in this species at least,
were growth rate and catabolite repression. 相似文献
5.
Baked-bean waste was found to be a favorable substrate for amylase production by Aspergillus foetidus NRRL 337. Under optimum conditions, the yields of α-amylase (EC 3.2.1.1) and glucoamylase (EC 3.2.1.3) were 47 and 226 U, respectively, per ml of the waste fermented. 相似文献
6.
The cloning of α-amylase gene ofS. occidentalis and the construction of starch digestible strain of yeast,S. cerevisiae AS. 2. 1364 with ethanol-tolerance and without auxotrophic markers used in fermentation industry were studied. The yeast/E.coli shuttle plasmid YCEp1 partial library ofS. occidentalis DNA was constructed and α-amylase gene was screened in S.cerevisiae by amylolytic activity. Several transformants with amylolysis were obtained and one of the fusion plasmids had an about 5.0
kb inserted DNA fragment, containing the upstream and downstream sequences of α-amylase gene fromS. occidentalis. It was further confirmed by PCR and sequence determination that this 5.0 kb DNA fragment contains the whole coding sequence
of α-amylase. The amylolytic test showed that when this transformant was incubated on plate of YPDS medium containing 1 %
glum and 1 % starch at 30°C for 48 h starch degradation zones could be visualized by staining with iodine vapour. α-amylase
activity of the culture filtratate is 740–780 mU/mL and PAGE shows that the yeast harboring fusion plasmids efficiently secreted
α-amylase into the medium, and the amount of the recombinant α-amylase is more than 12% of the total proteins in the culture
filtrate. These results showed that α-amylase gene can be highly expressed and efficiently secreted inS. cerevisiae AS. 2.1364, and the promotor and the terminator of α-amylase gene fromS. occidentalis work well inS. cercvisiac AS. 2.1364. 相似文献
7.
M. S. Madihah A. B. Ariff M. S. Khalil A. A. Suraini M. I. A. Karim 《Folia microbiologica》2001,46(3):197-204
A study of the kinetics and performance of solvent-yielding batch fermentation of individual sugars and their mixture derived
from enzymic hydrolysis of sago starch byClostridium acetobutylicum showed that the use of 30 g/L gelatinized sago starch as the sole carbon source produced 11.2 g/L total solvent,i.e. 1.5–2 times more than with pure maltose or glucose used as carbon sources. Enzymic pretreatment of gelatinized sago starch
yielding maltose and glucose hydrolyzates prior to the fermentation did not improve solvent production as compared to direct
fermentation of gelatinized sago starch. The solvent yield of direct gelatinized sago starch fermentation depended on the
activity and stability of amylolytic enzymes produced during the fermentation. The pH optima for α-amylase and glucoamylase
were found to be at 5.3 and 4.0–4.4, respectively. α-Amylase showed a broad pH stability profile, retaining more than 80%
of its maximum activity at pH 3.0–8.0 after a 1-d incubation at 37°C. SinceC. acetobutylicum α-amylase has a high activity and stability at low pH, this strain can potentially be employed in a one-step direct solvent-yielding
fermentation of sago starch. However, theC. acetobutylicum glucoamylase was only stable at pH 4–5, maintaining more than 90% of its maximum activity after a 1-d incubation at 37°C. 相似文献
8.
J. Bader L. Skelac S. Wewetzer M. Senz M. K. Popovi? R. Bajpai 《Applied Biochemistry and Microbiology》2012,48(2):182-187
Controlling the concentration of dissolved oxygen is a standard feature in aerobic fermentation processes but the measurement
of dissolved CO2 concentrations is often neglected in spite of its influence on the cellular metabolism. In this work room air and room air
supplemented with 5 and 10% carbon dioxide were used for aeration during the cultivation of the thermophilic microorganism
Bacillus caldolyticus (DSM 405) on starch to produce α-amylase (E.C. 3.2.1.1) and neutral protease (E.C. 3.4.24.27/28). The increased CO2 concentrations resulted in a 22% raise in activity of secreted α-amylase and a 43% raise in protease activity when compared
with aeration with un-supplemented room air. There was no effect on the final biomass concentration. Furthermore, the lag-phase
of fermentation was reduced by 30%, further increasing the productivity of α-amylase production. Determinations of dissolved
CO2 in the culture broth were conducted both in situ with a probe as well as using exhaust gas analysis and both the methods
of quantification showed good qualitative congruence. 相似文献
9.
Chittra Yeesang Supitchaya Chanthachum Benjamas Cheirsilp 《World journal of microbiology & biotechnology》2008,24(7):1195-1201
Low-cost sago starch was used as a carbon source for production of the exopolysaccharide kefiran by Lactobacillus kefiranofaciens. A simultaneous saccharification and fermentation process of sago starch for kefiran production was evaluated. Factors affecting
the process such as an initial pH, temperature, starch concentration, including a mixture of α-amylase and glucoamylase were
determined. The highest kefiran concentration of 0.85 g/l was obtained at the initial pH of 5.5, temperature of 30 °C, starch
concentration of 4% and mixed-enzymes with activity of 100 U/g-starch. The use of a mixture of α-amylase and glucoamylase
could enhance the productivity compared to the use of α-amylase alone. The optimal ratio of α-amylase to glucoamylase of 60:40
gave the highest kefiran production rate of 11.83 mg/l/h. This study showed that sago starch could serve as a low-cost substrate
for kefiran production. 相似文献
10.
Development of an arming yeast strain for efficient utilization of starch by co-display of sequential amylolytic enzymes on the cell surface 总被引:2,自引:2,他引:0
Murai T Ueda M Shibasaki Y Kamasawa N Osumi M Imanaka T Tanaka A 《Applied microbiology and biotechnology》1999,51(1):65-70
The construction of a whole-cell biocatalyst with its sequential reaction has been performed by the genetic immobilization
of two amylolytic enzymes on the yeast cell surface. A recombinant strain of Saccharomyces cerevisiae that displays glucoamylase and α-amylase on its cell surface was constructed and its starch-utilizing ability was evaluated.
The gene encoding Rhizopus oryzae glucoamylase, with its own secretion signal peptide, and a truncated fragment of the α-amylase gene from Bacillus stearothermophilus with the prepro secretion signal sequence of the yeast α factor, respectively, were fused with the gene encoding the C-terminal
half of the yeast α-agglutinin. The constructed fusion genes were introduced into the different loci of chromosomes of S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The glucoamylase and α-amylase
activities were not detected in the culture medium, but in the cell pellet fraction. The transformant strain co-displaying
glucoamylase and α-amylase could grow faster on starch as the sole carbon source than the transformant strain displaying only
glucoamylase.
Received: 16 June 1998 / Received last revision: 21 August 1998 / Accepted: 3 September 1998 相似文献
11.
A. -A. Amirul S. L. Khoo M. N. Nazalan M. S. Razip M. N. Azizan 《Folia microbiologica》1996,41(2):165-174
A. niger produced α-glucosidase, α-amylase and two forms of glucoamylase when grown in a liquid medium containing raw tapioca starch
as the carbon source. The glucoamylases, which formed the dominant components of amylolytic activity manifested by the organism,
were purified to homogeneity by ammonium sulfate precipitation, ion-exchange and two cycles of gel filtration chromatography.
The purified enzymes, designated GA1 and GA2, a raw starch digesting glucoamylase, were found to have molar masses of 74 and
96 kDa and isoelectric points of 3.8 and 3.95, respectively. The enzymes were found to have pH optimum of 4.2 and 4.5 for
GA1 and GA2, respectively, and were both stable in a pH range of 3.5–9.0. Both enzymes were thermophilic in nature with temperature
optimum of 60 and 65°C, respectively, and were stable for 1 h at temperatures of up to 60°C. The kinetic parametersK
m andV showed that with both enzymes the branched substrates, starch and amylopectin, were more efficiently hydrolyzed compared
to amylose. GA2, the more active of the two glucoamylases produced, was approximately six to thirteen times more active towards
raw starches compared to GA1. 相似文献
12.
The conformational analysis of polynorbornene (PNB) chains was investigated with the AM1, MM2, AMBER and OPLS methods taking into consideration the possibility of binding of norbornene monomers to each other at various positions, i.e. exo–exo, exo–endo, endo–endo. The chain that is formed by connecting exo–endo positions of the monomers has lower torsional barrier energy than those formed with bonds at other positions and has more flexibility. It is determined that the thredisyndiotactic chain formed by exo–endo addition adopts a helix structure and has a coil shape. The disyndiotactic chain formed by connecting norbornene monomers in mixed type has a linear structure. It is found that the repeat unit conformations of thredisyndiotactic and disyndiotactic chains of PNB are TGTG– and (TGTG–)2, respectively. 相似文献
13.
The present investigation was aimed at producing a thermostable and neutral glucoamylase (amyloglucosidase, EC 3.2.1.3) by
a thermophilic mould, Thermomucor indicae-seudaticae in submerged cultivation and testing its applicability in starch saccharification. Parametric optimization resulted in the
secretion of 30,000 U/l of glucoamylase in a synthetic medium (5% soluble starch, 0.1% yeast extract, 0.05% K2HPO4 and 0.01% MgSO4· 7H2O) using 5 × 106 spores/50 ml of a 3-day-old inoculum at 40 °C and 250 rev/min in shake flasks in 48 h. The enzyme secretion was not affected
to any significant extent by the tested additives and detergents. A 1.7-fold increase in glucoamylase secretion was attained
when T. indicae-seudaticae was grown in a laboratory fermenter. The enzyme alone catalysed the hydrolysis of soluble starch to an extent of 65%. A prior
treatment of starch with thermostable α-amylase and amylopullulanase, followed by glucoamylase, resulted in a greater extent of hydrolysis, 79 and 91%, respectively. 相似文献
14.
Rubinder K Chadha BS Singh N Saini HS Singh S 《Journal of industrial microbiology & biotechnology》2002,29(2):70-74
Thermomyces lanuginosus was subjected to three cycles of mutagenesis (UV/NTG) and a selection procedure to develop amylase-hyperproducing, catabolite-repression-resistant
and partially constitutive strains. One of the selected derepressed mutant strain III51, produced ∼7- and 3-fold higher specific activity of α-amylase (190 U/mg protein) and glucoamylase (105 U/mg protein), respectively,
compared to a wild-type parental strain. Further, the effect of production parameters on mutant strain III51 was studied using a Box–Behnken design. The regression models computed showed significantly high R
2 values of 96 and 97% for α-amylase and glucoamylase activities, respectively, indicating that they are appropriate for predicting
relationships between corn flour, soybean meal and pH with α-amylase and glucoamylase production. Journal of Industrial Microbiology & Biotechnology (2002) 29, 70–74 doi:10.1038/sj.jim.7000270
Received 05 July 2001/ Accepted in revised form 16 April 2002 相似文献
15.
The extracellular amylolytic system of Filobasidium capsuligenum consisted of an alpha-amylase (1,4-alpha-d-glucan glucanhydrolase, EC 3.2.1.1) and two forms of glucoamylase (1,4-alpha-d-glucan glucohydrolase, EC 3.2.1.3). The enzymes were purified by ammonium sulfate fractionation, repeated ion-exchange chromatography (DEAE-Sephadex A-50), and gel filtration (Sephadex G-25, Sephadex G-100 sf). alpha-Amylase had an optimum pH of 5.6 and an optimum temperature of 50 degrees C but was rapidly inactivated at higher temperature. The molecular weight was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 64,000. An acarbose concentration of 20 mug/ml was required for 50% inhibition of the alpha-amylase. Both glucoamylases are glycoproteins of identical molecular weight (60,000) and produce only glucose by exohydrolysis. The debranching activity of the glucoamylases was evidenced with substrates containing alpha-1,6 linkages. The pH optima were 5.0 to 5.6 for glucoamylase I and 4.8 to 5.3 for glucoamylase II. Glucoamylase I had a higher optimum temperature (55 degrees C) than glucoamylase II (50 degrees C) and was also more resistant to thermal inactivation. Only low acarbose concentrations (<0.1 mug/ml) were required to reduce the activity of the glucoamylases by 50%. 相似文献
16.
The GrpE protein from E. coli is a homodimer with an unusual structure of two long paired α-helices from each monomer interacting in a parallel arrangement
to form a “tail” at the N-terminal end. Using site-directed mutagenesis, we show that there is a key electrostatic interaction
involving R57 (mediated by a water molecule) that provides thermal stability to this “tail” region. The R57A mutant showed
a drop in T
m of 8.5°C and a smaller ΔH
u (unfolding) compared to wild-type for the first unfolding transition, but no significant decrease in dimer stability as shown
through equilibrium analytical ultracentrifugation studies. Another mutant (E94A) at the dimer interface showed a decrease
in ΔH
u but no drop in T
m for the second unfolding transition and a slight increase in dimer stability. 相似文献
17.
Subcellular localization of the starch-degrading enzymes in Vicia faba leaves was achieved by an electrophoretic transfer method through a starch-containing gel (SCG) and enzyme activity measurements. Total amylolytic and phosphorolytic activities were found predominantly in the extrachloroplastic fraction, whereas the debranching enzymes showed homogenous distribution between stromal and extrachloroplastic fractions. Staining of end products in the SCG revealed two isoforms of [alpha]-amylase (EC 3.2.1.1) and very low [beta]-amylase activity (EC 3.2.1.2) in the chloroplast preparation, whereas [alpha]- and [beta]-amylase exhibited higher activities in the crude extract. However, it is unclear whether the low [alpha]- and [beta]-amylase activities associated with the chloroplast are contamination or activities that are integrally associated with the chloroplast. Study of the diurnal fluctuation of the starch content and of the amylase activities under a 9-h/15-h photoperiod showed a 2-fold increase of the total amylolytic activity in the chloroplasts concurrent with the starch degradation in the dark. No fluctuation was detectable for the extrachloroplastic enzymes. The possible roles and function of the chloroplastic and extrachloroplastic hydrolytic enzymes are discussed. 相似文献
18.
The importance of 17 glutamate residues of a truncated Bacillus sp. strain TS-23 α-amylase (BACΔNC) was investigated by site-directed mutagenesis. The Ala- and Asp-substituted variants were overexpressed in the recombinant E. coli cells and the 54-kDa proteins were purified to nearly homologous by nickel-chelate chromatography. Glu-295, which locates in the conserved region III of amylolytic enzymes, mutations resulted in a complete loss of enzyme activity. The specific activity for E151A was decreased by more than 30%, while other variants showed activity comparable to that of BACΔNC. A decreased half-life at 70°C was observed for Glu-219 variants with respective to the wild-type enzyme, suggesting that replacement of Glu-219 by either Ala or Asp might have a significant destabilizing effect on the protein structure. 相似文献
19.
A simple structured model for biomass and extracellular enzyme production with recombinant Saccharomyces cerevisiae YPB-G 总被引:1,自引:0,他引:1
A simple structured model is proposed for simulating batch cultivation data on growth, substrate utilization, and heterologous
enzyme production of recombinant Saccharomyces cerevisiae YPB-G. The enzyme is a fusion protein displaying α-amylase and glucoamylase activities. Cell growth is modulated mainly by
intracellular substrate and ethanol concentrations. Intracellular substrate concentration is evaluated by means of the extracellular
substrate and biomass concentrations. Extracellular α-amylase and glucoamylase activities are taken to depend on biomass concentration.
The nine parameters of the proposed model are determined using nonlinear estimation techniques, and the model is validated
against experiments not used in parameter determination. The model developed simulates glucose consumption, cell mass, α-amylase
and glucoamylase production in a batch system. Simulation and experimental results are found to be in good agreement. Journal of Industrial Microbiology & Biotechnology (2002) 29, 111–116 doi:10.1038/sj.jim.7000281
Received 07 January 2002/ Accepted in revised form 22 May 2002 相似文献
20.
Kyung-Min Park So-Young Jun Kyoung-Hwa Choi Kwan-Hwa Park Cheon-Seok Park Jaeho Cha 《Applied microbiology and biotechnology》2010,86(2):555-566
We cloned and expressed the gene for an intracellular α-amylase, designated AmyB, from the hyperthermophilic bacterium Thermotoga neapolitana in Escherichia coli. The putative intracellular amylolytic enzyme contained four regions that are highly conserved among glycoside hydrolase
family (GH) 13 α-amylases. AmyB exhibited maximum activity at pH 6.5 and 75°C, and its thermostability was slightly enhanced
by Ca2+. However, Ca2+ was not required for the activity of AmyB as EDTA had no effect on enzyme activity. AmyB hydrolyzed the typical substrates
for α-amylase, including soluble starch, amylose, amylopectin, and glycogen, to liberate maltose and minor amount of glucose.
The hydrolytic pattern of AmyB is most similar to those of maltogenic amylases (EC 3.2.1.133) among GH 13 α-amylases; however,
it can be distinguished by its inability to hydrolyze pullulan and β-cyclodextrin. AmyB enzymatic activity was negligible
when acarbose, a maltotetraose analog in which a maltose residue at the nonreducing end was replaced by acarviosine, was present,
indicating that AmyB cleaves maltose units from the nonreducing end of maltooligosaccharides. These results indicate that
AmyB is a new type exo-acting intracellular α-amylase possessing distinct characteristics that distinguish it from typical
α-amylase and cyclodextrin-/pullulan-hydrolyzing enzymes. 相似文献