共查询到20条相似文献,搜索用时 15 毫秒
1.
K. Parvathi R. Naresh Kumar R. Nagendran 《World journal of microbiology & biotechnology》2007,23(5):671-676
Summary Biosorption of manganese from its aqueous solution using yeast biomass Saccharomyces cerevisiae and fungal biomass Aspergillus niger was carried out. Manganese biosorption equilibration time for A. niger and S. cerevisiae were found to be 60 and 20 min, with uptakes of 19.34 and 18.95 mg/g, respectively. Biosorption increased with rise in pH,
biomass, and manganese concentration. The biosorption equilibrium data fitted with the Freundlich isotherm model revealed
that A. niger was a better biosorbent of manganese than S. cerevisiae. 相似文献
2.
Y. P. Vinetsky A. M. Rozhkova A. M. Chulkin A. D. Satrutdinov O. A. Sinitsyna E. A. Fedorova A. O. Bekkarevich O. N. Okunev A. P. Sinitsyn 《Biochemistry. Biokhimii?a》2009,74(8):882-887
The gene encoding the xlnR xylanolytic activator of the heterologous fungus Aspergillus niger was incorporated into the Penicillium canescens genome. Integration of the xlnR gene resulted in the increase in a number of activities, i.e. endoxylanase, β-xylosidase, α-L-arabinofuranosidase, α-galactosidase, and feruloyl esterase, compared to the host P. canescens PCA 10 strain, while β-galactosidase, β-glucosidase, endoglucanase, and CMCase activities remained constant. Two different expression constructs were developed. The first consisted of the nucleotide sequence containing the mature P. canescens phytase gene under control of the axhA promoter region gene encoding A. niger (1,4)-β-D-arabinoxylan-arabinofuranohydrolase. The second construct combined the P. canescens phytase gene and the bgaS promoter region encoding homologous β-galactosidase. Both expression cassettes were transformed into P. canescens host strain containing xlnR. Phytase synthesis was observed only for strains with the bgaS promoter on arabinose-containing culture media. In conclusion, the bgaS and axhA promoters were regulated by different inducers and activators in the P. canescens strain containing a structural tandem of the axhA promoter and the gene of the xlnR xylanolytic activator. 相似文献
3.
Domain engineering of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> exoglucanases 总被引:2,自引:0,他引:2
To illustrate the effect of a cellulose-binding domain (CBD) on the enzymatic characteristics of non-cellulolytic exoglucanases, 10 different recombinant enzymes were constructed combining the Saccharomyces cerevisiae exoglucanases, EXG1 and SSG1, with the CBD2 from the Trichoderma reesei cellobiohydrolase, CBH2, and a linker peptide. The enzymatic activity of the recombinant enzymes increased with the CBD copy number. The recombinant enzymes, CBD2-CBD2-L-EXG1 and CBD2-CBD2-SSG1, exhibited the highest cellobiohydrolase activity (17.5 and 16.3 U mg –1 respectively) on Avicel cellulose, which is approximately 1.5- to 2-fold higher than the native enzymes. The molecular organisation of CBD in these recombinant enzymes enhanced substrate affinity, molecular flexibility and synergistic activity, contributing to their elevated action on the recalcitrant substrates as characterised by adsorption, kinetics, thermostability and scanning electron microscopic analysis. 相似文献
4.
Nehme N Mathieu F Taillandier P 《Journal of industrial microbiology & biotechnology》2008,35(7):685-693
This study examines the interactions that occur between Saccharomyces cerevisiae and Oenococcus oeni strains during the process of winemaking. Various yeast/bacteria pairs were studied by applying a sequential fermentation strategy which simulated the natural winemaking process. First, four yeast strains were tested in the presence of one bacterial strain leading to the inhibition of the bacterial component. The extent of inhibition varied widely from one pair to another and closely depended on the specific yeast strain chosen. Inhibition was correlated to weak bacterial growth rather than a reduction in the bacterial malolactic activity. Three of the four yeast strains were then grown with another bacteria strain. Contrary to the first results, this led to the bacterial stimulation, thus highlighting the importance of the bacteria strain. The biochemical profile of the four yeast fermented media exhibited slight variations in ethanol, SO(2) and fatty acids produced as well as assimilable consumed nitrogen. These parameters were not the only factors responsible for the malolactic fermentation inhibition observed with the first bacteria strain. The stimulation of the second has not been reported before in such conditions and remains unexplained. 相似文献
5.
Vania Castriani Fernandes da Silva Fabiano Jares Contesini Patrícia de Oliveira Carvalho 《Journal of industrial microbiology & biotechnology》2009,36(7):949-954
Considering the extraordinary microbial diversity and importance of fungi as enzyme producers, the search for new biocatalysts
with special characteristics and possible applications in biocatalysis is of great interest. Here, we report the performance
in the resolution of racemic ibuprofen of a native enantioselective lipase from Aspergillus niger, free and immobilized in five types of support (Accurel EP-100, Amberlite MB-1, Celite, Montmorillonite K10 and Silica gel).
Amberlite MB-1 was found to be the best support, with a conversion of 38.2%, enantiomeric excess of 50.7% and enantiomeric
ratio (E value) of 19 in 72 h of reaction. After a thorough optimization of several parameters, the E value of the immobilized Aspergillus niger lipase was increased (E = 23) in a shorter reaction period (48 h) at 35°C. Moreover, the immobilized Aspergillus niger lipase maintained an esterification activity of at least 80% after 8 months of storage at 4°C and could be reused at least
six times. 相似文献
6.
Two new effective microbial producers of inulinases were isolated from Jerusalem artichoke tubers grown in Thailand and identified
as Aspergillus niger TISTR 3570 and Candida
guilliermondii TISTR 5844. The inulinases produced by both these microorganisms were appropriate for hydrolysing inulin to fructose as the
principal product. An initial inulin concentration of ∼100 g l−1 and the enzyme concentration of 0.2 U g−1 of substrate, yielded 37.5 g l−1 of fructose in 20 h at 40°C when A. niger TISTR 3570 inulinase was the biocatalyst. The yield of fructose on inulin was 0.39 g g−1. Under identical conditions, the yeast inulinase afforded 35.3 g l−1 of fructose in 25 h. The fructose yield was 0.35 g g−1 of substrate. The fructose productivities were 1.9 g l−1 h−1 and 1.4 g l−1 h−1 for the mold and yeast enzymes, respectively. After 20 h of reaction, the mold enzyme hydrolysate contained 53% fructose
and more than 41% of initial inulin had been hydrolysed. Using the yeast enzymes, the hydrolysate contained nearly 38% fructose
at 25 h and nearly 36% of initial inulin had been hydrolysed. The A. niger TISTR 3570 inulinases exhibited both endo-inulinase and exo-inulinase activities. In contrast, the yeast inulinases displayed
mainly exo-inulinase activity. The mold and yeast crude inulinases mixed in the activity ratio of 5:1 proved superior to individual
crude inulinases in hydrolysing inulin to fructose. The enzyme mixture provided a better combination of endo- and exo-inulinase
activities than did the crude extracts of either the mold or the yeast individually. 相似文献
7.
Bo Young Jeon Soo Jin Kim Dae Hee Kim Byung Kwan Na Doo Hyun Park Hung Thuan Tran Ruihong Zhang Dae Hee Ahn 《Biotechnology and Bioprocess Engineering》2007,12(5):566-573
Aspergillus niger hyphae were found to grow with unliquefied potato starch under aerobic conditions, but did not grow under anaerobic conditions.
The raw culture ofA. niger catalyzed saccharification of potato starch to glucose, producing approximately 12 g glucose/L/day/ The extracellular enzyme
activity was decreased in proportion to incubation time, and approximately 64% of initial activity was maintained after 3
days. At 50°C,A. niger hyphae growth stopped, while the extracellular enzyme activity peaked. On the basis of theA. niger growth property and enzyme activity, we designed a serial bioreactor system composed of four different reactors. Fungal hyphae
were cultivated in reactor I at 30°C, uniquefied starch was saccharified to glycose by a fungal hyphae culture in reactors
II and III at 50°C, and glucose was fermented to ethanol bySaccharomyces cerevisiae in reactor IV. The total glucose produced by fungal hyphae in reactor I and saccharification in reactor II was about 42 g/L/day.
Ethanol production in reactor IV was approximately 22 g/L/day, which corresponds to about 79% of the theoretical maximum produced
from 55 g starch/L/day. 相似文献
8.
Lihua Hou 《Biotechnology letters》2009,31(5):671-677
Genome shuffling can improve complex phenotypes; however, there are several obstacles towards its broader applicability due
to increased complexity of eukaryotic cells. Here, we describe novel, efficient and reliable methods for genome shuffling
to increase ethanol production of Saccharomyces cerevisiae. Using yeast sexual and asexual reproduction by itself, mutant diploid cells were shuffled through highly efficient sporulation
and adequate cross among the haploid cells, followed by selection on the special plates. The selected strain obtained after
three round genome shuffling not only distinctly improved the resistance to ethanol, but also, increased ethanol yield by
up to 13% compared with the control. 相似文献
9.
10.
Gene silencing using siRNA has been examined in the industrially-important fungus, Aspergillus niger. Protoplasts of an A. niger strain containing a single genomic copy of the Escherichia coli uidA gene, encoding β-glucuronidase (GUS), under control of the A. niger glaA promoter at the same genomic locus, were exposed to siRNA targeted against the uidA gene. Down-regulation of uidA mRNA
and GUS activity by siRNA was observed in mycelia that developed from the protoplasts. The down-regulation was transient and
was not carried over to conidiation. We concluded that gene silencing by siRNA provides a relatively quick method for analysis
of gene function in A. niger. 相似文献
11.
A system for genotyping Saccharomyces cerevisiae is described based on a multiplex of ten microsatellite loci and the MAT locus. A database of genotypes has been developed
for 246 yeast strains, including a large set of commercial wine yeasts, as well as 35 sequenced natural isolates currently
being sequenced. The latter allow us, for the first time, to make direct comparisons of the relationship between DNA sequence
data and microsatellite-based genotypes. The genotyping system provides a rapid and valuable system for strain identification
as well as studying population genetics of S. cerevisiae. 相似文献
12.
Abed KF 《Journal of industrial microbiology & biotechnology》2008,35(9):1027-1032
The randomly amplified polymorphic DNA (RAPD) patterns of whole-cell lysates from five Aspergillus niger isolates, including one reference strain, two isolated from deep freeze, and two environmental strains from soil and plant infections, were investigated. PCR-RAPD analysis of genomic DNA was performed using eight primers (Tube-A1, Tube-A6, Tube-A17, Tube-B8, Tube-B11, Tube-B15, Tube-C5, Tube-C6). The RAPD assay discriminated between all strains. Comparison of deep freeze isolates showed identical RAPD patterns in some of the reference and environmental isolates. The data indicates that the RAPD technique is useful for fingerprinting A. niger. 相似文献
13.
Saccharomyces cerevisiae grows very poorly in dilute acid lignocellulosic hydrolyzate during the anaerobic fermentation for fuel ethanol production.
However, yeast cells grown aerobically on the hydrolyzate have increased tolerance for the hydrolyzate. Cultivation of yeast
on part of the hydrolyzate has therefore the potential of enabling increased ethanol productivity in the fermentation of the
hydrolyzate. To evaluate the ability of the yeast to grow in the hydrolyzate, fed-batch cultivations were run using the ethanol
concentration as input variable to control the feed-rate. The yeast then grew in an undetoxified hydrolyzate with a specific
growth rate of 0.19 h−1 by controlling the ethanol concentration at a low level during the cultivation. However, the biomass yield was lower for
the cultivation on hydrolyzate compared to synthetic media: with an ethanol set-point of 0.25 g/l the yield was 0.46 g/g on
the hydrolyzate, compared to 0.52 g/g for synthetic media. The main reason for the difference was not the ethanol production per se, but a significant production of glycerol at a high specific growth rate. The glycerol production may be attributed to an
insufficient respiratory capacity. 相似文献
14.
Katsuyama Y Miyahisa I Funa N Horinouchi S 《Applied microbiology and biotechnology》2007,73(5):1143-1149
For production of genistein from N-acetylcysteamine-attached p-coumarate (p-coumaroyl-NAC) supplemented to the medium, a chalcone synthase (CHS) gene from Glycyrrhiza echinata, a chalcone isomerase (CHI) gene from Pueraria lobata, and an isoflavone synthase (IFS) gene from G. echinata were placed under the control of the galactose-inducible GAL promoters in pESC vector and were introduced in Saccharomyces cerevisiae. When the recombinant yeast cells (0.5 g wet weight) were used as “enzyme bags” and incubated at 30°C for 48 h in 100 ml
of the buffer containing galactose and 1 mM (265 mg/l) p-coumaroyl-NAC, ca. 340 μg genistein/l was produced. Another system consisting of two enzyme bags was also generated for the
purpose of production of genistein from tyrosine. One enzyme bag was an Escherichia coli cell containing a phenylalanine ammonia-lyase gene from a yeast, a 4-coumarate/cinnamate:CoA ligase gene from the actinomycete
Streptomyces coelicolor A3(2), the CHS gene, and the CHI gene, in addition to the acetyl-CoA carboxylase gene from Corynebacterium
glutamicum, all of which were under the control of the isopropyl-β-d-thiogalactopyranoside-inducible T7 promoter, and thus producing (S)-naringenin from tyrosine. The other enzyme bag was a S.
cerevisiae cell containing the IFS gene. Coincubation of the E.
coli cells (0.5 g wet weight) and S. cerevisiae cells (0.5 g wet weight) at 26°C for 60 h in 20 ml of the buffer containing 3 mM (543 mg/l) tyrosine as the starting substrate
yielded ca. 6 mg genistein/l. 相似文献
15.
Novel additives that act as substratum for attachment of the yeast cells, increased ethanol production in Saccharomyces cerevisiae. The addition of 2 g rice husk, straw, wood shavings, plastic pieces or silica gel to 100 ml medium enhanced ethanol production by 30–40 (v/v). Six distillery strains showed an average enhancement of 34 from 4.1 (v/v) in control to 5.5 (v/v) on addition of rice husk. The cell wall bound glycogen increased by 40–50 mg g –1 dry yeast while intracellular glycogen decreased by 10–12 mg g–1 dry yeast in cells grown in presence of substratum 相似文献
16.
A constitutive level of a mycelium-bound lipolytic activity from Aspergillus niger MYA 135 was strongly increased by 97% in medium supplemented with 2% olive oil. The constitutive lipase showed an optimal
activity in the pH range of 3.0–6.5, while the mycelium-bound lipase activity produced in the presence of olive oil had two
pH optima at pH 4 and 7. Interestingly, both lipolytic sources were cold-active showing high catalytic activities in the temperature
range of 4–8°C. These mycelium-bound lipase activities were also very stable in reaction mixtures containing methanol and
ethanol. In fact, the constitutive lipase maintained almost 100% of its activity after exposure by 1 h at 37°C in ethanol.
A simple methodology to evaluate suitable transesterification activities in organic solvents was also reported. 相似文献
17.
18.
Xiao-Wei Yu Yong-Quan Li Shi-Miao Zhou Yu-Yi Zheng 《World journal of microbiology & biotechnology》2007,23(8):1091-1098
Aspergillus niger with mycelium-bound tannase activity was employed to investigate the synthesis of propyl gallate from gallic acid and 1-propanol
in organic solvents. The effects of various organic solvents (log P: −1.0 to 6.6) on the enzymatic reactions showed that benzene (log P: 2.0) was the most suitable solvent. The water content and protonation state of mycelium-bound enzyme both had significant
effects on the activity of tannase. The maximum molar conversion (65%) was achieved with 7.3% (v/v) 1-propanol and 5.56 mM
gallic acid at stirring speeds of 200 rev/min, 40 °C in presence of anhydrous sodium sulfate and PEG-10,000. Enzyme specificity
for the alcohol portion (C1–C8) of the ester showed that the optimum synthesis was observed with alcohols ranging from C3 to C5. 相似文献
19.
20.
The aim of this study was to evaluate the MPK1 (SLT2) gene deletion upon filamentous growth induced by isoamyl alcohol (IAA) in two haploid industrial strains of Saccharomyces cerevisiae using oligonucleotides especially designed for a laboratory S. cerevisiae strain. The gene deletion was performed by replacing part of the open reading frames from the target gene with the KanMX gene. The recombinant strains were selected by their resistance to G418, and after deletion confirmation by polymerase chain
reaction, they were cultivated in a yeast extract peptone dextrose medium + 0.5% IAA to evaluate the filamentous growth in
comparison to wild strains. Mpk1 derivatives were obtained for both industrial yeasts showing the feasibility of the oligonucleotides especially designed
for a laboratory strain (Σ1278b) by Martinez-Anaya et al. (In yeast, the pseudohyphal phenotype induced by isoamyl alcohol
results from the operation of the morphogenesis checkpoint. J Cell Sci 116:3423–3431, 2003). The filamentation rate in these
derivatives was significantly lower for both strains, as induced by IAA. This drastic reduction in the filamentation ability
in the deleted strains suggests that the gene MPK1 is required for IAA-induced filamentation response. The growth curves of wild and derivative strains did not differ substantially.
It is not known yet whether the switch to filamentous growth affects the fermentative characteristics of the yeast or other
physiological traits. A genetically modified strain for nonfilamentous growth would be useful for these studies, and the gene
MPK1 could be a target gene. The feasibility of designed oligonucleotides for this deletion in industrial yeast strains is shown. 相似文献