共查询到20条相似文献,搜索用时 15 毫秒
1.
Palmero Llamas D de Cara Gonzalez M Iglesias Gonzalez C Ruíz Lopez G Tello Marquina JC 《Journal of industrial microbiology & biotechnology》2008,35(11):1405-1409
The mycelial growth of 18 Fusarium solani strains isolated from sea beds of the south-eastern coast of Spain was tested on potato-dextrose-agar adjusted to different
osmotic potentials with either KCl or NaCl (−1.50 to −144.54 bars) in 10 °C intervals ranging from 15 to 35 °C. Fungal growth
was determined by measuring colony diameter after 4 days of incubation. Mycelial growth was maximal at 25 °C. The quantity
and frequency pattern of mycelial growth of F. solani differ significantly at 15 and 25 °C, with maximal growth occurring at the highest water potential tested (−1.50 bars); and
at 35 °C, with a maximal mycelial growth at −13.79 bars. The effect of water potential was independent of salt composition.
The general growth pattern of F. solani showed declining growth at potentials below −41.79 bars. Fungal growth at 35 °C was always higher than that grow at 15 °C,
of all the water potentials tested. Significant differences observed in the response of mycelia to water potential and temperature
as main and interactive effects. The viability of cultures was increasingly inhibited as the water potential dropped, but
some growth was still observed at −99.56 bars. These findings could indicate that marine strains of F. solani have a physiological mechanism that permits survival in environments with low water potential. The observed differences in
viability and the magnitude of growth could indicate that the biological factors governing potential and actual growth are
affected by osmotic potential in different ways. 相似文献
2.
R Rech C F Cassini A Secchi M A Z Ayub 《Journal of industrial microbiology & biotechnology》1999,23(2):91-96
We studied the utilization of protein-hydrolyzed sweet cheese whey as a medium for the production of β-galactosidase by the
yeasts Kluyveromyces marxianus CBS 712 and CBS 6556. The conditions for growth were determined in shake cultures. The best growth occurred at pH 5.5 and
37°C. Strain CBS 6556 grew in cheese whey in natura, while strain CBS 712 needed cheese whey supplemented with yeast extract. Each yeast was grown in a bioreactor under these
conditions. The strains produced equivalent amounts of β-galactosidase. To optimize the process, strain CBS 6556 was grown
in concentrated cheese whey, resulting in a higher β-galactosidase production. The β-galactosidase produced by strain CBS
6556 produced maximum activity at 37°C, and had low stability at room temperature (30°C) as well as at a storage temperature
of 4°C. At −4°C and −18°C, the enzyme maintained its activity for over 9 weeks.
Received 20 January 1999/ Accepted in revised form 30 April 1999 相似文献
3.
Xylanase, β-glucosidase, β-xylosidase, endoglucanase and polygalacturonase production fromCurvularia inaequalis was carried out by means of solid-state and submerged fermentation using different carbon sources. β-Glucosidase. β-xylosidase,
polygalacturonase and xylanase produced by the microorganisms were characterized. β-Glucosidase presented optimum activity
at pH 5.5 whereas xylanase, poly-galacturonase and β-xylosidase activities were optimal at pH 5.0. Maximal activity of β-glucosidase
was determined at 60°C, β-xylosidase at 70°C, and polygalacturonase and xylanase at 55°C. These enzymes were stable at acidic
to neutral pH and at 40–45 °C. The crude enzyme solution was studied for the hydrolysis of agricultural residues. 相似文献
4.
Moreland D. Gibbs Rosalind A. Reeves Anwar Sunna Peter L. Bergquist 《Current microbiology》1999,39(6):351-357
A β-mannanase gene (manA) was isolated from the extremely thermophilic bacterium Dictyoglomus thermophilum Rt46B.1. ManA is a single-domain enzyme related to one group of β-mannanases (glycosyl hydrolase family 26). The manA gene was expressed in the heat-inducible vector pJLA602 and the expression product, ManA, purified to homogeneity. The recombinant
ManA is a monomeric enzyme with a molecular mass of 40 kDa and an optimal temperature and pH for activity of 80°C and 5.0.
In the absence of substrate, the enzyme showed no loss of activity at 80°C over 16 h, while at 90°C the enzyme had a half-life
of 5.4 min. Hydrolysis of the galactomannan locust bean gum (LBG) by purified ManA released mainly mannose, mannobiose, and
mannotriose, confirming that ManA is an endo-acting β-mannanase. Sequence comparisons with related β-mannanases has allowed
the design of consensus PCR primers for the identification and isolation of related genes.
Received: 7 June 1999 / Accepted: 6 July 1999 相似文献
5.
The mycelial growth of 10 Fusarium culmorum strains isolated from water of the Andarax riverbed in the provinces of Granada and Almeria in southeastern Spain was tested on potato-dextrose-agar adjusted to different osmotic potentials with either KCl or NaCl (?1.50 to ?144.54 bars) at 10°C intervals ranging from 15° to 35°C. Fungal growth was determined by measuring colony diameter after 4 d of incubation. Mycelial growth was maximal at 25°C. The quantity and capacity of mycelial growth of F. culmorum were similar at 15 and 25°C, with maximal growth occurring at ?13.79 bars water potential and a lack of growth at 35°C. The effect of water potential was independent of salt composition. The general growth pattern of Fusarium culmorum growth declined at potentials below ?13.79 bars. Fungal growth at 25°C was always greater than growth at 15°C, at all of the water potentials tested. Significant differences were observed in the response of mycelia to water potential and temperature as main and interactive effects. The number of isolates that showed growth was increasingly inhibited as the water potential dropped, but some growth was still observable at ?99.56 bars. These findings could indicate that F. culmorum strains isolated from water have a physiological mechanism that permits survival in environments with low water potential. Propagules of Fusarium culmorum are transported long distances by river water, which could explain the severity of diseases caused by F. culmorum on cereal plants irrigated with river water and its interaction under hydric stress or moderate soil salinity. The observed differences in growth magnitude and capacity could indicate that the biological factors governing potential and actual growth are affected by osmotic potential in different ways. 相似文献
6.
Two chimeric genes, XynA-Bs-Glu-1 and XynA-Bs-Glu-2, encoding Aspergillus sulphureus β-xylanase (XynA, 26 kDa) and Bacillus subtilis β-1,3-1,4-glucanase (Bs-Glu, 30 kDa), were constructed via in-fusion by different linkers and expressed successfully in Pichia pastoris. The fusion protein (50 kDa) exhibited both β-xylanase and β-1,3-1,4-glucanase activities. Compared with parental enzymes, the moiety activities were decreased in fermentation supernatants. Parental XynA and Bs-Glu were superior to corresponding moieties in each fusion enzymes because of lower Kn higher kcat. Despite some variations, common optima were generally 50°C and pH 3.4 for the XynA moiety and parent, and 40°C and pH 6.4 for the Bs-Glu counterparts. Thus, the fusion enzyme XynA-Bs-Glu-1 and XynA-Bs-Glu-2 were bifunctional. 相似文献
7.
Laura Mazzaferro Lucrecia Piñuel Marisol Minig Javier D. Breccia 《Archives of microbiology》2010,192(5):383-393
We screened for microorganisms able to use flavonoids as a carbon source; and one isolate, nominated Stilbella fimetaria SES201, was found to possess a disaccharide-specific hydrolase. It was a cell-bound ectoenzyme that was released to the medium
during conidiogenesis. The enzyme was shown to cleave the flavonoid hesperidin (hesperetin 7-O-α-rhamnopyranosyl-β-glucopyranoside)
into rutinose (α-rhamnopyranosyl-β-glucopyranose) and hesperetin. Since only intracellular traces of monoglycosidase activities
(β-glucosidase, α-rhamnosidase) were produced, the disaccharidase α-rhamnosyl-β-glucosidase was the main system utilized by
the microorganism for hesperidin hydrolysis. The enzyme was a glycoprotein with a molecular weight of 42224 Da and isoelectric
point of 5.7. Even when maximum activity was found at 70°C, it was active at temperatures as low as 5°C, consistent with the
psychrotolerant character of S. fimetaria. Substrate preference studies indicated that the enzyme exhibits high specificity toward 7-O-linked flavonoid β-rutinosides.
It did not act on flavonoid 3-O-β-rutinoside and 7-O-β-neohesperidosides, neither monoglycosylated substrates. In an aqueous
medium, the α-rhamnosyl-β-glucosidase was also able to transfer rutinose to other acceptors besides water, indicating its
potential as biocatalyst for organic synthesis. The monoenzyme strategy of S. fimetaria SES201, as well as the enzyme substrate preference for 7-O-β-flavonoid rutinosides, is unique characteristics among the microbial
flavonoid deglycosylation systems reported. 相似文献
8.
LHS Guimarães H F Terenzi J A Jorge MLTM Polizeli 《Journal of industrial microbiology & biotechnology》2001,27(4):265-270
An extracellular (conidial) and an intracellular (mycelial) alkaline phosphatase from the thermophilic fungus Scytalidium thermophilum were purified by DEAE-cellulose and Concanavalin A-Sepharose chromatography. These enzymes showed allosteric behavior either
in the presence or absence of MgCl2, BaCl2, CuCl2, and ZnCl2. All of these ions increased the maximal velocity of both enzymes. The molecular masses of the conidial and mycelial enzymes,
estimated by gel filtration, were 162 and 132 kDa, respectively. Both proteins migrated on SDS-PAGE as a single polypeptide
of 63 and 58.5 kDa, respectively, suggesting that these enzymes were dimers of identical subunits. The best substrate for
the conidial and mycelial phosphatases was p-nitrophenylphosphate, but β-glycerophosphate and other phosphorylated compounds also served as substrates. The optimum pH
for the conidial and mycelial alkaline phosphatases was 10.0 and 9.5 in the presence of AMPOL buffer, and their carbohydrate
contents were about 54% and 63%, respectively. The optimum temperature was 70–75°C for both activities. The enzymes were fully
stable up to 1 h at 60°C. These and other properties suggested that the alkaline phosphatases of S. thermophilum might be suitable for biotechnological applications. Journal of Industrial Microbiology & Biotechnology (2001) 27, 265–270.
Received 10 January 2001/ Accepted in revised form 10 July 2001 相似文献
9.
Tiquia SM 《Microbial ecology》2011,62(3):679-689
The potential effects of urbanization on the bioavailability of dissolved organic carbon (DOC) were tested by determining
the extracellular enzyme activities of the heterotrophic microbial communities of the Rouge River. The activities of 19 enzymes
were monitored across two water samples (river water and groundwater) at different spatial and temporal scales. High phosphatase,
esterase, and aminopeptidase activities was observed in site 9 (site most exposed to anthropogenic sources) showed higher
concentrations of DOC compared to sites 1 and 8 (sites exposed to less anthropogenic sources), where moderate activities of
diverse range of enzymes were observed. High relative contributions of phosphatase, esterase, and aminopeptidase activities
to the overall enzyme activity as observed in site 9 stressed the increased importance of peptides as C source for heterotrophic
communities and high in-stream carbon processing, which account for high nonspecific extracellular enzyme activities. In contrast,
high contribution of glycosyl hydrolases occurred consistently across all sites, which highlights the significance of microbial
detrital and plant biomass as carbon sources. Majority of the enzymes showed evidence of activity at various extents during
spring and summer. However, higher activities of leucine aminopeptidase, valine aminopeptidase, β-glucosidase, and α-mannosidase
were observed in the summer; and alkaline phosphatase and α-glucosidase in the spring. The results presented here suggest
a shift in organic carbon bioavailability across all sites of contrasting urbanization, despite similarities in DOC concentrations.
Hence, API ZYM technique can be used as an effective indicator of river water and groundwater system health across an urban
gradient. 相似文献
10.
Regulation and Seasonal Dynamics of Extracellular Enzyme Activities in the Sediments of a Large Lowland River 总被引:1,自引:0,他引:1
We tested whether seasonal changes in the sources oforganic substances for microbial metabolism were reflected changes in
the activities of five extracellular enzymes in the eighth order lowland River Elbe, Germany. Leucine aminopeptidase showed
the highest activities in the water column and the sediments, followed by phosphatase > β-glucosidase > α-glucosidase > exo-1,4-β-glucanase.
Individual enzymes exhibited characteristic seasonal dynamics, as indicated by their relative contribution to cumulative enzyme
activity. Leucine aminopeptidase was significantly more active in spring and summer. In contrast, the carbohydrate-degrading
enzymes peaked in autumn, and β-glucosidase activity peaked once again in winter. Thus, in sediments, the ratio of leucine
aminopeptidase/β-glucosidase reached significant higher medians in spring and summer (5-cm depth: ratio 7.7; 20-cm depth:
ratio 10.1) than in autumn and winter (5-cm depth: ratio 3.7, 20-cm depth: ratio 6.3). Therelative activity of phosphatase
in the sediments was seasonally related to both the biomass of planktonic algae as well as to the high content of total particulate
phosphorus in autumn and winter. Due to temporal shifts in organic matter supply and changes in the storage capacity of sediments,
the seasonal peaks of enzyme activities in sediments exhibited a time lag of 2–3 months compared to that in the water column,
along with a significant extension of peak width. Hence, our data show that the seasonal pattern of extracellular enzyme activities
provides a sensitive approach to infer seasonal or temporary availability of organic matter in rivers from autochthonous and
allochthonous sources. From the dynamics of individual enzyme activities, a consistent synoptic pattern of heterotrophic functioning
in the studied river ecosystem could be derived. Our data support the revised riverine productivity model predicting that
the metabolism of organic matter in high-order rivers is mainly fuelled by autochthonous production occurring in these reaches
and riparian inputs. 相似文献
11.
Cesar Vanderlei Nascimento Flávio Henrique Moreira Souza Douglas Chodi Masui Francisco Assis Leone Rosane Marina Peralta João Atílio Jorge Rosa Prazeres Melo Furriel 《Journal of microbiology (Seoul, Korea)》2010,48(1):53-62
The effect of several carbon sources on the production of mycelial-bound β-glucosidase by Humicola grisea var. thermoidea in submerged fermentation was investigated. Maximum production occurred when cellulose was present in the culture medium,
but higher specific activities were achieved with cellobiose or sugarcane bagasse. Xylose or glucose (1%) in the reaction
medium stimulated β-glucosidase activity by about 2-fold in crude extracts from mycelia grown in sugarcane bagasse. The enzyme
was purified by ammonium sulfate precipitation, followed by Sephadex G-200 and DEAE-cellulose chromatography, showing a single
band in PAGE and SDS-PAGE. The β-glucosidase had a carbohydrate content of 43% and showed apparent molecular masses of 57
and 60 kDa, as estimated by SDS-PAGE and gel filtration, respectively. The optimal pH and temperature were 6.0 and 50°C, respectively.
The purified enzyme was thermostable up to 60 min in water at 55°C and showed half-lives of 7 and 14 min when incubated in
the absence or presence of 50 mM glucose, respectively, at 60°C. The enzyme hydrolyzed p-nitrophenyl-β-D-glucopyranoside, p-nitrophenyl-β-Dgalactopyranoside, p-nitrophenyl-β-D-fucopyranoside, p-nitrophenyl-β-D-xylopyranoside, o-nitrophenyl-β-Dgalactopyranoside, lactose, and cellobiose. The best synthetic and natural substrates were p-nitrophenyl-β-Dfucopyranoside and cellobiose, respectively. Purified enzyme activity was stimulated up to 2-fold by glucose
or xylose at concentrations from 25 to 200 mM. The addition of purified or crude β-glucosidase to a reaction medium containing
Trichoderma reesei cellulases increased the saccharification of sugarcane bagasse by about 50%. These findings suggest that H. grisea var. thermoidea β-glucosidase has a potential for biotechnological applications in the bioconversion of lignocellulosic materials. 相似文献
12.
Production of β-Mannanase and β-Mannosidase from Aspergillus awamori K4 and Their Properties 总被引:6,自引:0,他引:6
β-Mannanase and β-mannosidase from Aspergillus awamori K4 was produced by solid culture with coffee waste and wheat bran. The optimum composition for enzyme production was 40%
coffee waste–60% wheat bran. Two enzymes were partially purified. Optimum pH was about 5 for both enzymes, and optimum temperature
was around 80°C for β-mannanase and 60–70°C for β-mannosidase. These enzymes produced some oligosaccharides from glucomannan
and galactomannan by their hydrolyzing and transferring activities. β-Mannanase hydrolyzed konjak and locust bean gum 39.1%
and 15.8%, respectively. Oligosaccharides of various molecular size were released from glucomannan of konjak, but on the addition
of cellulase, mannobiose was released selectively. In locust bean gum, tetra-, tri-, and disaccharides (mannobiose) were mainly
released by K4 β-mannanase. Tetra- and trisaccharides were heterooligosaccharides consisting of galactose and mannose residues.
K4 β-mannosidase had a transglycosylation action, transferring mannose residue to alcohols and sugars like fructose.
Received: 24 April 2000/Accepted: 20 October 2000 相似文献
13.
K Mattila L Carpen L Raaska H-L Alakomi T Hakkarainen M S Salkinoja-Salonen 《Journal of industrial microbiology & biotechnology》2000,24(6):410-420
Open circuit potentials of stainless steels increased when immersed in the Baltic Sea. The ennoblement potential was +200
mVsce in 40 to 50 days when sea water temperature was below 52°C and +300–400 mVsce within <40 days at around 102°C. Ennoblement occurred in a laboratory ecosystem at 232°C in 20 to 30 days, and at 262°C in
<20 days, but no ennoblement occurred at A322°C within 40 days. By the time the ennoblement was complete, compact microcolonies
covered 1–10% of the steel surface. Nutrient enrichment of Baltic Sea water by twofold above the natural levels increased
microbial growth but attenuated open circuit potential increase of the stainless steels. Exposure of the ennobled stainless
steels to similar levels of nutrients did not reverse the already developed open circuit potentials. Attenuation of the ennobling
response of the stainless steels by increases of temperature and eutrophication suggests a role for microorganisms which is
crucial for the electrochemical behaviour of steels in brackish Baltic Sea water. Journal of Industrial Microbiology & Biotechnology (2000) 24, 410–420.
Received 02 November 1999/ Accepted in revised form 24 March 2000 相似文献
14.
Tamotsu Hoshino Fumihiro Terami Oleg B. Tkachenko Motoaki Tojo Naoyuki Matsumoto 《Mycoscience》2010,51(2):98-103
The snow mold fungus, Sclerotinia borealis, shows optimal growth at 4°C on potato dextrose agar (PDA) and can grow even at subzero temperature. Its mycelial growth
was improved on frozen PDA at −1°C and on PDA containing potassium chloride (KCl) (water potential, −4.27 to −0.85 MPa) or
d(−) sorbitol (−3.48 to −0.92 MPa). Its optimal growth temperature shifted from 4 to 10°C on PDA amended with KCl or sorbitol,
indicating that inherent optimal growth occurs at high temperatures. These results suggest that S. borealis uses concentrated nutrients in the frozen environment and that such physiologic characteristics are critical for the fungus
to prevail at subzero temperatures. 相似文献
15.
S Hayashi S Sako H Yokoi Y Takasaki K Imada 《Journal of industrial microbiology & biotechnology》1999,22(3):160-163
β-Glucosidase hydrolyzing cellobiose was extracted from Aureobasidium sp ATCC 20524 and purified to homogeneity. The molecular mass was estimated to be about 331 kDa. The enzyme contained 26.5%
(w/w) carbohydrate. The optimum pH and temperature for the enzyme reaction were pH 4 and 80°C, respectively. The enzyme was
stable at a wide range of pH, 2.2–9.8, after 3 h and at 75°C for 15 min. The kinetic parameters were determined. The enzyme
was relatively stable against typical organic enzyme inhibitors. The enzyme also hydrolyzed gentiobiose, p-nitrophenyl-β-glucoside and salicin.
Received 05 November 1998/ Accepted in revised form 14 February 1999 相似文献
16.
Yu. V. Burtseva V. V. Sova M. V. Pivkin S. D. Anastyuk V. I. Gorbach T. N. Zvyagintseva 《Applied Biochemistry and Microbiology》2010,46(6):648-656
The capacity to produce exocellular enzymes was studied for 92 samples of fungi from various marine habitats in the Sea of
Okhotsk (78 strains) and the Sea of Japan (14 strains). Strains producing highly active glycanases and glycosidases were found.
Synthesis of O-glycosylhydrolases was stimulated by addition of laminaran to the nutrient medium. Highly purified N-acetyl-β-D-glucosaminidase
was isolated from the marine fungus Penicillium canescens. The molecular weight of the enzyme determined by SDS-Na-electrophoresis was 68 kDa. The enzyme displayed maximum activity
at pH 4.5 and temperature 45°C. Inactivation half-time of the enzyme at 50°C was 25 min. N-acetyl-β-D-glucosaminidase hydrolyzed
both β-glucosaminide and β-galactosaminide bonds and possessed a high transglycosylating activity. 相似文献
17.
Alexandre Favarin Somera Marita Gimenez Pereira Luis Henrique Souza Guimarães Maria de Lourdes Teixeira de Moraes Polizeli Héctor Francisco Terenzi Rosa Prazeres Melo Furriel João Atílio Jorge 《Journal of microbiology (Seoul, Korea)》2009,47(3):270-276
Aspergillus versicolor grown on xylan or xylose produces two β-xylosidases with differences in biochemical properties and degree of glycosylation. We investigated the alterations in the
biochemical properties of these β-xylosidases after deglycosylation with Endo-H or PNGase F. After deglycosylation, both enzymes migrated faster in PAGE or
SDS-PAGE exhibiting the same Rf. Temperature optimum of xylan-induced and xylose-induced β-xylosidases was 45°C and 40°C, respectively, and 35°C after deglycosylation. The xylan-induced enzyme was more active at
acidic pH. After deglycosylation, both enzymes had the same pH optimum of 6.0. Thermal resistance at 55°C showed half-life
of 15 min and 9 min for xylose- and xylan-induced enzymes, respectively. After deglycosylation, both enzymes exhibited half-lives
of 7.5 min. Native enzymes exhibited different responses to ions, while deglycosylated enzymes exhibited identical responses.
Limited proteolysis yielded similar polypeptide profiles for the deglycosylated enzymes, suggesting a common polypeptide core
with differential glycosylation apparently responsible for their biochemical and biophysical differences. 相似文献
18.
The culture-medium composition was optimised, on a shake-flask scale, for simultaneous production of high activities of endoglucanase
and β-glucosidase by Thermoascus aurantiacus using statistical factorial designs. The optimised medium containing 40.2 g l−1 Solka Floc as the carbon source and 9 g l−1 soymeal as the organic nitrogen source yielded 1130 nkat ml−1 endoglucanase and 116 nkat ml−1β-glucosidase activities after 264 h as shake cultures. In addition, good levels of β-xylanase (3479 nkat ml−1) and low levels of filter-paper cellulase, β-xylosidase, α-l-arabinofuranosidase, β-mannanase, β-mannosidase, α-galactosidase and β-galactosidase were detected. Batch fermentation in
a 5-l laboratory fermentor using the optimised medium allowed the production of 940 nkat ml−1 endoglucanase and 102 nkat ml−1β-glucosidase in 192 h. Endoglucanase and β-glucosidase showed optimum activity at pH 4.5 and pH 5, respectively, and they
displayed optimum activity at 75 °C. Endoglucanase and β-glucosidase showed good stability at pH values 4–8 and 4–7, respectively,
after a prolonged incubation (48 h at 50 °C). Endoglucanase had half-lives of 98 h at 70 °C and 4.1 h at 75 °C, while β-glucosidase
had half-lives of 23.5 h at 70 °C and 1.7 h at 75 °C. Alkali-treated bagasse, steam-treated wheat straw, Solka floc and Sigmacell
50 were 66, 48.5, 33.5 and 14.4% hydrolysed by a crude enzyme complex of T. aurantiacus in 50 h.
Received: 12 November 1999 / Accepted: 14 November 1999 相似文献
19.
Chitinase,β-1,3-glucanase, cellulase, xylanase and protease activity were detected in a crude enzyme preparation obtained from a slime
mold (Badhamia utricularis) which was grown on autoclaved mycelia ofPholiota nameko in a petri dish. The optimal pH of the enzyme preparation for lytic activity against fruit bodies ofLentinus edodes was 4.0, and those ofβ-1,3-glucanase and cellulase were the same. On the other hand, chitinase and protease showed optimal activity at pH 5.0 and
8.0, respectively. The lytic activity was stable below 40°C but completely inactivated at 70°C, and was most stable at pH
5.0. The studies of the optimal pH, thermal stability, and pH stability, and isoelectric focusing analysis of the enzyme preparation
suggest that chitinase,β-1,3-glucanase and cellulase activities may be responsible for lysis of fruit bodies of some mushrooms. The crude enzyme preparation
from the slime mold lysed fruit bodies of several mushrooms more efficiently than did commercial lytic enzymes preparations
(Driselase and Usukizyme). 相似文献
20.
A number of substrates were tested for the cultivation of microorganisms to produce a host of enzymes. The effect of different
substrates (wheat and rice straw, sugar cane waste, wood waste), incubation temperatures (20–40°C), initial pH levels (3.5–9.0),
incubation periods (0–72 hours) and nitrogen sources (ammonium sulfate, urea, peptone, yeast extract, sodium nitrate) on growth
and α-amylase activity was studied for the native and mutant strains. Maximum enzyme activity was observed at 1.5% wheat straw
for Aspergillus niger FCBP-198 and An-Ch-4.7 and at 2% wheat straw for An-UV-5.6, with sodium nitrate as a principle nitrogen source. The optimum
temperature for maximum enzyme activity was 30°C for the parental strain, while An-UV-5.6 and An-Ch-4.7 thrived well at 32.5°C.
The best conditions of pH and incubation duration were 4.5 and 48 hours, respectively, for all the strains. Mass production
under preoptimized growth conditions demonstrated the suitability of wheat straw for swift mycelial colonization and viability. 相似文献