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1.
O. García-Kirchner M. Segura-Granados P. Rodríguez-Pascual 《Applied biochemistry and biotechnology》2005,121(1-3):347-359
The hydrolytic activity of fungal originated β-glucosidase is exploited in several biotechnological processes to increase
the rate and extent of saccharification of several cellulosic materials by hydrolyzing the cellobiose which inhibits cellulases.
In a previous presentation, we reported the screening and liquid fermentation with Aspergillus niger, strain C-6 for β-glucosidase production at shake flask cultures in a basal culture medium with mineral salts, corn syrup liquor, and
different waste lignocellulosic materials as the sole carbon source obtaining the maximum enzymatic activity after 5–6 d of
8.5 IU/mL using native sugar cane bagasse. In this work we describe the evaluation of fermentation conditions: growth temperature,
medium composition, and pH, also the agitation and aeration effects for β-glucosidase production under submerged culture using
a culture media with corn syrup liquor (CSL) and native sugar cane bagasse pith as the sole carbon source in a laboratory
fermenter. The maximum enzyme titer of 7.2 IU/mL was obtained within 3 d of fermentation. This indicates that β-glucosidase
productivity by Aspergillus niger
C-6 is function of culture conditions, principally temperature, pH, culture medium conditions, and the oxygen supply given in
the bioreactor. Results obtained suggest that this strain is a potential microorganism that can reach a major level of enzyme
production and also for enzyme characterization. 相似文献
2.
William R. Gibbons Nathan S. Pulscher Erling J. Ringquist 《Applied biochemistry and biotechnology》1992,37(2):177-189
To develop a procedure for submerged cultivation of the edible fungusPleurotus sajor caju, we investigated the organism’s tolerance to sodium meta bisulfite and acidic pH levels. These factors were evaluated as
means of controlling bacterial and/or fungal contamination. Trials were conducted in 500 mL Erlenmeyer flasks that contained
200–300 mL of a 3% glucose, 0.5% yeast extract medium, and either 0-0.225% SMB (wt/wt) added, or initially adjusted to pH
levels between 1.8–6.5. Inoculated flasks were incubated 7–10 d at 30°C and 200 rpm in an environmental shaker, with samples
removed daily to determine mycelial dry weights. Results showed that SMB levels up to 0.05% significantly lengthened the lag
phase (from 27 to 79 h) but had no effect on productivity. Maximal productivity varied between 0.054–0.057 g/L/h, whereas
overall productivity was 0.042–0.045 g/L/h. Biomass concentrations ranged from 7.1–8.4 g/L. Higher SMB levels rapidly reduced
productivities and yields, eventually inactivating the inoculum above 0.1% SMB. In one instance the SMB tolerance of P.sajor caju was increased to 0.075% by repeatedly exposing the organism to sublethal levels of the chemical; however, this trait was
not maintained in later trials. Bacterial contaminants were detected at SMB concentrations of 0.02–0.07%, while fungal contaminants
were found up to 0.125% SMB. Thus it appears that SMB might be useful in controlling bacterial contamination, but may not
be as effective against fungal contaminants. The optimum pH range in terms of lag phase length, biomass yield, and productivity
was 4.5–5.5, however, in certain trialsP. sajor caju still exhibited good growth parameters at pH levels as low as 3.8–4.0. pH levels below 3.8 and above 5.8 greatly reduced
both growth rates and yields. Acidic pH levels (3.8–4.5) were also effective in controlling the majority of bacterial and
fungal contaminants encountered. Therefore low pH or perhaps a combination of low pH and SMB should be useful in developing
a large scale system for submerged cultivation ofP. sajor caju. 相似文献
3.
Trichoderma is one of the most promising biocontrol agents against plant fungal diseases. In this study, a transgenic strain of Trichoderma atroviride was characterized. The transgenic strain contains an endochitinase gene (ThEn-42) driven by the cellulase promoter cbh1 of T. reesei for overexpression of ThEn-42. The culture filtrates of the transformant and the parental strain grown in eight different media were evaluated for chitinase
and antifungal enzyme production based on activity gels, protein profiles, and antifungal activities. Results demonstrated
that chitinases are important components and synergistic interactions play a key role in the antagonistic action of T. atroviride. Moreover, altering medium nutrient concentration and composition led to enhanced production of antifungal enzymes, a potential
strategy for mass production. Two of the culture filtrates contained almost pure endochitinase, and could be excellent commercial
sources for this enzyme. Several culture filtrates were highly antifungal. Two filtrates were so effective in biocontrol of
a fungal pathogen, Penicillium digitatum, that they not only inhibited spore germination but destroyed the spores completely when 20 μl of culture filtrate (corresponding
to approximately 104 μg of total protein) was applied in a total volume of 150 μl (approximately 0.7 mg protein ml−1). 相似文献
4.
Mycelial pellet formation by Rhizopus oryzae ATCC 20344 总被引:2,自引:0,他引:2
Factors in a cultivation medium affecting fungal growth morphology and funmaric acid production by Rhizopus oryzae ATCC 20344 were investigated. These factors included the initial pH value and trace metals such as zinc, magnesium, iron,
and manganese in the cultivation medium. It was found that a significant change in the growth morphology of R. oryzae ATCC 20344 occurs when the initial pH value is varied. A lower initial pH value in the cultivation medium was inhibitory
to fungal growth, and fast growth in the cultivation medium at a higher initial pH value promoted, the formation of large
pellets or filamentous forms. Trace metals in the cultivation media also had significant effects on pellet formation and fumaric
acid fermentation. 相似文献
5.
Tamás Juhász Anita Egyházi Kati Réczey 《Applied biochemistry and biotechnology》2005,121(1-3):243-254
The hydrolysis of cellulose to the water-soluble products cellobiose and glucose is achieved via synergistic action of cellulolytic
proteins. The three types of enzymes involved in this process are endoglucanases, cellobiohydrolases, and β-glucosidases.
One of the best fungal cellulase producers is Trichoderma reesei RUT C30. However, the amount of β-glucosidases secreted by this fungus is insufficient for effective cellulose conversion.
We investigated the production of cellulases and β-glucosidases in shake-flask cultures by applying three pH-controlling strategies:
(1) the pH of the production medium was adjusted to 5.8 after the addition of seed culture with no additional pH adjustment
performed, (2) the pH was adjusted to 6.0 daily, and (3) the pH was maintained at 6.0 by the addition of Tris-maleate buffer to the growth medium. Different carbon sources—Solka
Floc 200, glucose, lactose, and sorbitol—were added to standard Mandels nutrients. The lowest β-glucosidase activities were
obtained when no pH adjustment was done regardless of the carbon source employed. Somewhat higher levels of β-glucosidase
were measured in the culture filtrates when daily pH adjustment was carried out. The effect of buffering the culture medium
on β-glucosidase liberation was most prominent when a carbon source inducing the production of other cellulases was applied. 相似文献
6.
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
7.
Emilia Curotto Marisol Concha Victoriano Campos Adriane M. F. Milagres Nelson Duran 《Applied biochemistry and biotechnology》1994,48(2):107-116
Xylanase production byPenicillium janthinellum using 10–100 mM of 2,2-dimethylsuccinate (DMS) buffer, in a range of pH 4.5-6.0 was studied. The enzyme activity was enhanced
using oat xylan as the carbon source. Under these conditions a culture produced 1.14 Μmol/ min (11.4 U/mL or 84.4 U/mg) of
Β-xylanase after 5 d of growth in a 10-mM buffer solution at pH 4.5. Protease was absent in the DMS buffer except when 100
mM phosphate buffer at pH 6.0 was used (4 U/mL). Β-Xylosidase was only found at a pH of 4.5 in all the buffer concentrations.
At a 50 mM DMS buffer concentration at pH 4.5 Β- xylanases were induced by both oat and birch xylans, having a greater effect with oat spelt xylans.
Electrophoretic analyses showed that the birchwood xylan induction exhibited different proteins profiles. No Β-xylosidase
or Β- glucosidase was induced until d 5. The Β-xylanases were rapidly inactivated at 50‡C, however, birch xylanase appeared to
be more stable than oat xylanase.
Using oat xylan as an inductor, theΒ-xylosidase andΒ-glucosidase were 85 and 91 U/L, respectively, on d 7. The xylanase produced by induction from sugar cane bagasse hydrolyzate
was used for pulp biobleaching. A 20% decrease on the Kappa value in Kraft pulp using the culture extract was obtained. These
selective growth conditions led us to modulate the xylanase production for pulp delignification. 相似文献
8.
Chairattanamanokorn P Imai T Kondo R Ukita M Prasertsan P 《Applied biochemistry and biotechnology》2006,128(3):195-204
To select a thermotolerant fungal strain for decolorization of wastewaters, ligninolytic enzyme production (lignin peroxidase,
manganese peroxidase [MnP], and laccase), decolorization, and removal of total phenol and chemical oxygen demand (COD) were
detected. Thirty-eight fungal strains were studied for enzyme production at 35 and 43°C on modified Kirk agar medium including
2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and MnCl2. Thirteen strains grew on manganese-containing agar and provided green color on ABTS-containing agar plates under culture
at 43°C. Decolorization of wastewater from alcohol distillery (WAD) by these strains was compared under static culture at
43°C, and Pycnoporus coccineus FPF 97091303 showed the highest potential. Thereafter, immobilized mycelia were compared with free mycelia for WAD decolorization
under culture conditions of 43°C and 100 rpm. The immobilized mycelia on polyurethane foam enhanced the ligninolytic enzyme
production as well as total phenol and color removal. At about the same COD removal, MnP and laccase produced by immobilized
mycelia were 2 and 19 times higher than by free mycelia; the simultaneous total phenol and color removal were 3.1 and 1.5
times higher than the latter. Moreover, decolorization of synthesis dye wastewater was carried out at 43°C and 100 rpm. More
than 80% of 300 mg/L of reactive blue-5 was decolorized by the immobilized mycelia within 1 to 2 d for four cycles. 相似文献
9.
L. A. Sáenz-Carbonell I. E. Maldonado-Mendoza O. Moreno-Valenzula R. Clau-Uitz M. López-Meyer C. Oropeza V. M. Loyola-Vargas 《Applied biochemistry and biotechnology》1993,38(3):257-267
The release of alkaloids from root culturesDatura stramonium andCatharanthus roseus and thiophenes from root cultures ofTagetes patula was found to increase when the pH of the culture media (ranging from 4.8 to 7.0) was reduced to 3.5. The extent of the effect
was different in each type of culture. Increases ranged from 4- to 20-fold, which in some cases accounted for 75% of the total
secondary metabolite pool produced per flask. When the release of individual metabolites was measured, even larger increases,
were observed (nearly 400-fold for ajmalicine). Increased release of alkaloids fromC. roseus roots were also observed in cultures growing in a 14-L fermentor, when the medium pH was reduced. Reduction of the pH of
the media did not affect growth of the root cultures in subsequent subcultures. The importance of this treatment as a stategy
to improve the recovery of secondary metabolites from producing cultures is discussed. 相似文献
10.
The effect of carbon source and its concentration, inoculum size, yeast extract concentration, nitrogen source, pH of the
fermentation medium, and fermentation temperature on β-glucosidase production by Kluyveromyces marxianus in shake-flask culture was investigated. These were the independent variables that directly regulated the specific growth
and β-glucosidase production rate. The highest product yield, specific product yield, and productivity of β-glucosidase occurred
in the medium (pH 5.5) inoculated with 10% (v/v) inoculum of the culture. Cellobiose (20 g/L) significantly improved β-glucosidase
production measured as product yield (Y
P/S
) and volumetric productivity (Q
P
) followed by sucrose, lactose, and xylose. The highest levels of productivity (144 IU/[L·h]) of β-glucosidase occurred on
cellobiose in the presence of CSL at 35°C and are significantly higher than the values reported by other researchers on almost
all other organisms. The thermodynamics and kinetics of β-glucosidase production and its deactivation are also reported. The
enzyme was substantially stable at 60°C and may find application in some industrial processes. 相似文献
11.
Madhavan Nampoothiri K Roopesh K Chacko S Pandey A 《Applied biochemistry and biotechnology》2005,120(2):97-108
Escherichia coli NCIM 2569 was evaluated for its potential for amidase production under submerged fermentation. Among the various amide compounds
screened, maximum substrate specificity and enzyme yield (8.1 U/mL) were obtained by using 1% acetamide. Fermentation was
carried out at 30°C in shake-flask culture under optimized process conditions. A maximum of 0.52 U/mL of intracellular amidase
activity was also obtained from cells incubated for 24 h. Studies were also performed to elucidate the optimal conditions
(gel concentration, initial biomass, curing period of beads, and calcium ion concentration in the production medium) for immobilization
of whole cells. By using E. coli cells entrapped in alginate, a maximum of 6.2 U/mL of enzyme activity was obtained after 12 h of incubation under optimized
conditions. Using the immobilized cells, three repeated batches were carried out successfully, and 85% of the initial enzyme
activity was retained in the second and third batches. The study indicated that the immobilized E. coli cells offered certain advantages such as less time for maximum enzyme production, more stability in the enzyme production
rate, and repeated use of the biocatalyst. 相似文献
12.
Production of l-glutamate oxidase (GluOx) by Streptomyces sp. N1 was investigated by controlling culture pH at 6.2, 6.7, 7.0, and 7.3 in a 5-l stirred fermentor. The corresponding GluOx activities obtained were 2.8, 4.2, 6.0, and 5.3 U/mL, respectively. Microbial
growth was inhibited by increasing the medium pH from 6.2 to 7.0. The inhibitory effect was also observed in plate colony
growth under incubation with a different initial pH value. The effect of calcium on GluOx production was also studied in the
pH-controlled bioreactor. When the culture pH was controlled at 6.2 or 7.0, GluOx production could not be improved or was
only improved slightly by initial addition of calcium to the medium. However, when the culture pH was kept at 6.7, initial
Ca2+ addition (60 mM) conspicuously enhanced GluOx production up to 9.3 U/mL, which was about twofold of that without Ca2+ addition. The enzyme production level was the highest ever reported in the literature. During fermentation the inhibition
of cell growth by Ca2+ addition was observed. For the morphological changes, the cells mostly existed as pellets in the medium without Ca2+ addition, whereas few pellets were found and almost all the cells were dispersed mycelia in the broth with Ca2+ addition. 相似文献
13.
The biodegradation of fluoranthene, a high molecular weight polycyclic aromatic hydrocarbon (PAH), was investigated in submerged
culture using the wood decaying fungus isolated from forest locality in Gujarat, India. The basidiomycete fungal isolate was
found to have an ability to grow on sabaroud dextrose agar containing 50 mgl−1 of each naphthalene, anthracene, acenaphthene, benzo (a) anthracene, pyrene, flouranthene, carbazole, and biphenyl. The involvement
of extracellular fungal peroxidases such as manganese peroxidase (MnP) and laccase (Phenol oxidase) in the degradation of
fluoranthene was studied. On the eighth day of incubation 54.09% of 70 mg l−1 fluoranthene was removed. There after no PAHs removal was observed till the 20th day of the incubation period. The isolate
was identified as Pleurotus ostreatus by 18S rRNA, 5.8S rRNA, and partial 28S rRNA gene sequencing. To the best of our knowledge this is the first time Pleurotus ostreatus have been reported to degrade such a high concentration of fluoranthene within much lower time period of incubation. Depletion
in the residual fluoranthene in the culture medium was determined by HPLC. Attempts were made to identify the degradation
product in the culture medium with the help of FT-IR, NMR, and HPTLC analysis. In the present study positive correlation between
fluoranthene degradation and the ligninolytic enzyme (MnP and laccase) production is observed, thus this isolate can play
an effective role for bioremediation of PAHs contaminated sites. 相似文献
14.
Jesús Torres-Bacete Miguel Arroyo Raquel Torres-Guzmán Isabel de La Mata Carmen Acebal M. Pilar Castillón 《Applied biochemistry and biotechnology》2005,126(2):119-131
The culture medium for Streptomyces lavendulae ATCC 13664 was optimized on a shake-flask scale by using a statistical factorial design for enhanced production of penicillin
acylalse. This extracellularenzyme recently has been reported to bea penicillin Kacylase, presenting also high hydrolytic
activity against penicillin V and other natural aliphatic penicillins such as penicillin K, penicillin F, and penicillin dihydroF,.
The factorial design indicated that the main factors that positively affect penicillin acylase production by S. lavendulae were the concentration of yeast extract and the presence of oligoelements in the fermentation medium, whereas the presence
of olive oil in the medium had no effect on enzyme production. An initial concentration of 2.5% (w/v) yeast extract and 3
μg/mL of CuSO4·5H2O was found to be best for acylase production. In such optimized culture medium, fermentation, of the microorganism yielded
289 IU/L of enzyme in 72 h when employing a volume medium/volume flask ratio of 0.4 and a 300-rpm shaking speed. The presence
of copper, alone and in combination with other metals, stimulated biomass as well as penicillin acylase production. The time
course of penicillin acylase production was also studied in the optimized medium and conditions. Enzyme production showed
catabolite repression by different carbon sources such as glucose, lactose, citrate, glycerol, and glycine. 相似文献
15.
Lim JM Kim SW Hwang HJ Joo JH Kim HO Choi JW Yun JW 《Applied biochemistry and biotechnology》2004,119(2):159-170
Optimization of submerged culture conditions for the production of mycelial growth and exopolysaccharides (EPSs) by Collybia maculata was investigated. The optimum temperature and the initial pH for EPS production in a shake-flask culture of C. maculata were found to be 20°C and 5.5, respectively. Among the various medium’s constituents examined, glucose, Martone A-1, K2HPO4, and CaCl2 were the most suitable carbon, nitrogen, and mineral sources for EPS production, respectively. The optimum concentration
of the medium’s ingredients determined using the orthogonal matrix method was as follows: 30 g/L of glucose, 20 g/L of Martone
A-1, 1g/L of K2HPO4, and 1g/L of CaCl2. Under the optimized culture conditions, the maximum concentration of EPSs in a 5-L stirred-tank reactor was 2.4 g/L, which
was approximately five times higher than that in the basal medium. A comparative fermentation result showed that the EPS productivity
in an airlift reactor was higher than that in the stirred-tank reactor despite the lower mycelial growth rate. The specific
productivities and the yield coefficients in the airlift reactor were higher than those in the stirred-tank reactor even though
the volumetric productivities were higher in the stirred-tank reactor than in the airlift reactor. 相似文献
16.
Luciano Belato Alves Graciette Matioli Flávio Faria De Moraes Gisella Maria Zanin José Eduardo Olivo 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):399-402
Different culture media have been testedfor the production of the enzyme CGTase (cyclodextringlycosyltransferase) from Bacillus firmus (strain #37). The concentration of different carbon and nitrogen sources have been varied and the enzyme activity, cell concentration, reducing sugars, total reducing sugars, soluble protein and pH have been followed during cultivation. Results indicate that higher concentrations of yeast extract and polypeptone lead to increased synthesis of CGTase, whereas when starch is substituted by glucose there is a drastic inhibition of CGTase production. 相似文献
17.
Thereza Christina Vessoni Penna Angela Faustino Jozala Thomas Rodolfo Gentille Adalberto Pessoa Jr. Olivia Cholewa 《Applied biochemistry and biotechnology》2006,129(1-3):334-346
Nisin, a bacteriocin produced during the exponential growth phase of Lactococcus lactis ATCC 11454, inhibits the growth of a broad range of Grampositive bacteria. Gram-negative bacteria can also be inhibited by nisin with EDTA. In this study, nisin production was assayed by the agar diffusion method using Lactobacillus sake ATCC 15521 and a recombinant Escherichia coli DH5-α expressing the recombinant green fluorescent protein as the nisin-susceptible test organisms. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU/mL of medium) and converted to standard nisin concentration (Nisaplin®, 25 mg of pure nisin with an activity of 1×106 AU/mL). The expression and release of nisin by L. lactis in skimmed milk (9.09% total solids) with Man Rugosa Shepeer-Bacto Lactobacilli broth (1∶1) was monitored in a 5 L New Brunswick fermentor. Combining EDTA with nisin increased the bactericidal effect of nisin on the bacteria examined. The presence of EDTA was necessary to inhibit E. coli growth with nisin. L. sake was shown to be a good indicator for the evaluation of nisin release in the culture media, including with the addition of EDTA. 相似文献
18.
Chattopadhyay S Srivastava AK Bisaria VS 《Applied biochemistry and biotechnology》2002,102(1-6):381-393
The root explants of the germinated seedlings of Podophyllum hexandrum were grown in MS medium supplemented with indole acetic acid (IAA) (2 mg/L) and activated charcoal (0.5%), and healthy callus
culture was obtained after incubation for 3 wk at 20°C. The cultivation of plant cells in shake flask was associated with
problems such as clumping of cells and browning of media, which were solved by the addition of pectinase and polyvinylpyrrolidone.
The effect of major media components and carbon source was studied on the growth and podophyllotoxin production in suspension
culture. It was found that glucose was a better carbon source than sucrose and that NH4
+:NO3
− ratio (total nitrogen concentration of 60 mM) and PO4
3− did not have much effect on the growth and product formation. The relative effect of culture parameters (inoculum level,
pH, IAA, glucose, NH4
+:NO3
− ratio, and PO4
3−) on the overall growth and product response of the plant cell suspension culture was further investigated by Plackett-Burman
design. This indicated that inoculum level, glucose, IAA, and pH had significant effects on growth and production of podophyllotoxin.
To identify the exact optimum concentrations of these parameters on culture growth and podophyllotoxin production, central
composite design experiments were formulated. The overall response equations with respect to growth and podophyllotoxin production
as a function of these culture parameters were developed and used to determine the optimum concentrations of these parameters,
which were pH 6.0, 1.25 mg/L of IAA, 72 g/L of glucose, and inoculum level of 8 g/L. 相似文献
19.
A cellulase production process was developed by growing the fungi Trichoderma reesei and Aspergillus phoenicis on dairy manure. T. reesei produced a high total cellulase titer (1.7 filter paper units [FPU]/mL, filter paper activity) in medium containing 10 g/L
of manure (dry basis [w/w]), 2 g/L KH2PO4, 2 mL/L of Tween-80, and 2mg/L of CoCl2. However, β-glucosidase activity in the T. reesei-enzyme system was very low. T. reesei was then cocultured with A. phoenicis to enhance the β-glucosidase level. The mixed culture resulted in a relatively high level of total cellulase (1.54 FPU/mL)
and β-glucosidase (0.64 IU/mL). The ratio of β-glucosidase activity to filter paper activity was 0.41, suitable for hydrolyzing
manure cellulose. The crude enzyme broth from the mixed culture was used for hydrolyzing the manure cellulose, and the produced
glucose was significantly (p<0.01) higher than levels obtained by using the commercial enzyme or the enzyme broth of the pure culture T. reesei. 相似文献
20.
Pinotti Laura M. Silva Rosineide G. Giordano Roberto C. Giordano Raquel L. C. 《Applied biochemistry and biotechnology》2002,98(1-9):679-686
This article reports studies concerning the production of penicillin G acylase (PGA) by Bacillus megaterium. This enzyme has industrial use in the hydrolysis of penicillin G to obtain 6-aminopenicillanic acid, an essential intermediate
for the production of semisynthetic β-lactam antibiotics. Although most microorganisms produce the enzyme intracellularly,
B. megaterium provides extracellular PGA. The enzyme production by microorganisms involves several steps, resulting in a many operational
variables to be studied. The study of the inoculum is an important step to be accomplished, before addressing other issues
such as culture optimization and downstream processing. In this study, using a standard inoculum as reference, several runs
were performed aiming at the definition of operational conditions in the PGA production. Cell concentration and PGA activity
in the production medium were measured after 24, 48, and 72 h of the beginning of the production phase. This study encompasses
the duration of the inoculum germination phase and the concentration of cells used to startup the germination. Based on these
results, PGA productivity during the production phase was maximized. The selected values for these variables were 1.5 × 107 spores/mL of germination medium, germination during 24 h, and 72 h for the production phase. 相似文献