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1.
Constant medium feeding rate and intermittent fed-batch fermentation strategies were investigated aiming to increase the yields
of γ-decalactone production by Yarrowia lipolytica, using methyl ricinoleate as substrate and ricinoleic acid source. The accumulation of another compound, 3-hydroxy-γ-decalactone,
was also analyzed since it derives from the direct precursor of γ-decalactone thereby providing information about the enzymatic
activities of the pathway. Both strategies were compared with the traditional batch mode in terms of overall productivity
and yield in respect to the substrate. Although the productivity of γ-decalactone was considerably higher in the batch mode
(168 mg l−1 h−1), substrate conversion to lactone (73 mg γ-decalactone g−1) was greater in the intermittent fed-batch giving 6.8 g γ-decalactone l−1. This last strategy therefore has potential for γ-decalactone production at an industrial level. 相似文献
2.
Téllez-Téllez M Fernández FJ Montiel-González AM Sánchez C Díaz-Godínez G 《Applied microbiology and biotechnology》2008,81(4):675-679
Pleurotus ostreatus showed atypical laccase production in submerged vs. solid-state fermentation. Cultures grown in submerged fermentation produced
laccase at 13,000 U l−1, with a biomass production of 5.6 g l−1 and four laccase isoforms. However, cultures grown in solid-state fermentation had a much lower laccase activity of 2,430 U
l−1, biomass production of 4.5 g l−1, and three laccase isoforms. These results show that P. ostreatus performs much better in submerged fermentation than in solid-state fermentation. This is the first report that shows such
atypical behavior in the production of extracellular laccases by fungi. 相似文献
3.
Smita Srivastava Ashok Kumar Srivastava 《In vitro cellular & developmental biology. Plant》2012,48(1):73-84
Azadirachtin, a well-known biopesticide, is a secondary metabolite extracted from the seeds of Azadirachta indica. In the present study, azadirachtin was produced in hairy roots of A. indica, generated by Agrobacterium rhizogenes-mediated transformation of leaf explants. Liquid cultures of A. indica hairy roots were developed with a liquid-to-flask volume ratio of 0.15. The kinetics of growth and azadirachtin production
were established in a basal plant growth medium containing MS medium major and minor salts, Gamborg’s medium vitamins, and
30 g l−1 sucrose. The highest azadirachtin accumulation in the hairy roots (up to 3.3 mg g−1) and azadirachtin production (∼44 mg l−1) was obtained on Day 25 of the growth cycle, with a biomass production of 13.3 g l−1 dry weight. To enhance the production of azadirachtin, a Plackett–Burman experimental design protocol was used to identify
key medium nutrients and concentrations to support high root biomass production and azadirachtin accumulation in hairy roots.
The optimal nutrients and concentrations were as follows: 40 g l−1 sucrose, 0.19 g l−1 potassium dihydrogen phosphate, 3.1 g l−1 potassium nitrate, and 0.41 g l−1 magnesium sulfate. Concentrations were determined by a central composite design protocol and verified in shake-flask cultivation.
The optimized medium composition yielded a root biomass production of 14.2 g l−1 and azadirachtin accumulation of 5.2 mg g−1, which was equivalent to an overall azadirachtin production of 73.84 mg l−1, 68% more than that obtained under non-optimized conditions. 相似文献
4.
Hadeer Lazim Houda Mankai Nedra Slama Insaf Barkallah Ferid Limam 《Journal of industrial microbiology & biotechnology》2009,36(4):531-537
The purpose of the present research is to study the production of thermophilic alkaline protease by a local isolate, Streptomyces sp. CN902, under solid state fermentation (SSF). Optimum SSF parameters for enzyme production have been determined. Various
locally available agro-industrial residues have been screened individually or as mixtures for alkaline protease production
in SSF. The combination of wheat bran (WB) with chopped date stones (CDS) (5:5) proved to be an efficient mixture for protease
production as it gave the highest enzyme activity (90.50 U g−1) when compared to individual WB (74.50 U g−1) or CDS (69.50 U g−1) substrates. This mixed solid substrate was used for the production of protease from Streptomyces sp. CN902 under SSF. Maximal protease production (220.50 U g−1) was obtained with an initial moisture content of 60%, an inoculum level of 1 × 108 (spore g−1 substrate) when incubated at 45°C for 5 days. Supplementation of WB and CDS mixtures with yeast extract as a nitrogen source
further increased protease production to 245.50 U g−1 under SSF. Our data demonstrated the usefulness of solid-state fermentation in the production of alkaline protease using
WB and CDS mixtures as substrate. Moreover, this approach offered significant benefits due to abundant agro-industrial substrate
availability and cheaper cost. 相似文献
5.
Guo T Tang Y Zhang QY Du TF Liang DF Jiang M Ouyang PK 《Journal of industrial microbiology & biotechnology》2012,39(3):401-407
Clostridium beijerinckii mutant strain IB4, which has a high level of inhibitor tolerance, was screened by low-energy ion implantation and used for
butanol fermentation from a non-detoxified hemicellulosic hydrolysate of corn fiber treated with dilute sulfuric acid (SAHHC).
Evaluation of toxicity showed C. beijerinckii IB4 had a higher level of tolerance than parent strain C. beijerinckii NCIMB 8052 for five out of six phenolic compounds tested (the exception was vanillin). Using glucose as carbon source, C. beijerinckii IB4 produced 9.1 g l−1 of butanol with an acetone/butanol/ethanol (ABE) yield of 0.41 g g−1. When non-detoxified SAHHC was used as carbon source, C. beijerinckii NCIMB 8052 grew well but ABE production was inhibited. By contrast, C. beijerinckii IB4 produced 9.5 g l−1 of ABE with a yield of 0.34 g g−1, including 2.2 g l−1 acetone, 6.8 g l−1 butanol, and 0.5 g l−1 ethanol. The remarkable fermentation and inhibitor tolerance of C. beijerinckii IB4 appears promising for ABE production from lignocellulosic materials. 相似文献
6.
François Coutte Didier Lecouturier Saliha Ait Yahia Valérie Leclère Max Béchet Philippe Jacques Pascal Dhulster 《Applied microbiology and biotechnology》2010,87(2):499-507
Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air–liquid contactor to prevent foam formation. Three different configurations
were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a
submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen
uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory
bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume
was in the same range: 242, 230, and 188 mg l−1 for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l−1 for BB1, 207 mg l−1 for BB2, and 393 mg l−1 for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer
coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with
the submerged polypropylene membrane. 相似文献
7.
Herrera-Valencia VA Contreras-Pool PY López-Adrián SJ Peraza-Echeverría S Barahona-Pérez LF 《Current microbiology》2011,63(2):151-157
The aim of this study was to investigate the potential of the green microalga Chlorella saccharophila as a source of oil for biodiesel production. We evaluated for the first time, the effect of salinity and/or nitrogen depletion
(ND) on cell growth, lipid accumulation and lipid profile in this microalga. The fatty acid methyl esters (FAME) identified
for C. saccharophila in this study consisted of C-16:0, C-18:0, C-18:1 cis, and C-18:1 trans. Among these, C-18:1 (indicator of biodiesel quality)
was the main FAME found, representing approximately 76 and 80% of total FAME under normal and ND growing conditions, respectively.
Under a normal growing condition this microalga showed 154.63 mg l−1 d−1, 63.33 mg l−1 d−1, and 103.73 mg l−1 of biomass productivity, lipid productivity, and FAME yield, respectively. The higher biomass productivity (159.58 mg l−1 d−1), lipid productivity (99.33 mg l−1 d−1), and FAME yield (315.53 mg l−1) were obtained under the ND treatment. In comparison to other related studies, our results suggest that C. saccharophila can be considered as a suitable source of oil for biodiesel production. 相似文献
8.
In vitro cultures of Berberis buxifolia were established using thidiazuron (4.5, 23 and 45 mM) or picloram (4 and 40 mM) as plant growth regulators for sustaining
growth. For producing berberine, a two-stage culture was performed. In the first step, thidiazuron or picloram were used for
biomass production followed by the production stage where benzylaminopurine (4.4 mM) was added as a plant growth regulator.
Berberine yields (102 mg g−1 DW) and in vitro shoot cultures (200 mg g−1 DW) were significantly lower than those of whole plants in the field (416 mg g−1 DW). The highest productivity (0.18 mg 1−1 day−1) was attained using picloram (either 4 on 40 mM) in the first stage for producing biomass. 相似文献
9.
Ana Coste Laurian Vlase Adela Halmagyi Constantin Deliu Gheorghe Coldea 《Plant Cell, Tissue and Organ Culture》2011,106(2):279-288
We investigated the effects of plant growth regulators [6-benzyladenine (BA), kinetin (Kin), 6-γ,γ-dimethylallylaminopurine
(2iP), thidiazuron (TDZ) and α-naphthaleneacetic acid (NAA)], modified Murashige and Skoog (MS) medium containing 10 mM NH4
+ and 5 mM NO3
− and supplemented with 2iP, BA, Kin and NAA (MSM medium), and two elicitors [jasmonic acid (JA), and salicylic acid (SA)],
on plant growth and accumulation of hypericins (hypericin and pseudohypericin) and hyperforin in shoot cultures of Hypericum hirsutum and H. maculatum. Our data suggested that culture of shoots on MS medium supplemented with BA (0.4 mg l−1) or Kin (0.4 mg l−1) enhanced production of hypericins in H. maculatum and hyperforin in H. hirsutum. Hypericins and hyperforin concentrations decreased in both species when TDZ (0.4 mg l−1) was added to the MS medium. Also, TDZ induced hyperhydric malformations and necrosis of regenerated shoots. Cultivation
of H. maculatum on MSM medium resulted in approximately twofold increased production of hypericins compared to controls, and the growth of
H. hirsutum shoots on the same medium led to a 6.16-fold increase in hyperforin production. Of the two elicitors, SA was more effective
in stimulating the accumulation of hypericins. At 50 μM, SA enhanced the production of hypericin (7.98-fold) and pseudohypericin
(13.58-fold) in H. hirsutum, and, at 200 μM, enhanced the production of hypericin (2.2-fold) and pseudohypericin (3.94-fold) in H. maculatum. 相似文献
10.
Lang YJ Bai L Ren YN Zhang LH Nagata S 《Extremophiles : life under extreme conditions》2011,15(2):303-310
Using ectoine-excreting strain Halomonas salina DSM 5928T, we developed a new process for high-efficiency production of ectoine, which involved a combined process of batch fermentation
by growing cells and production by resting cells. In the first stage, batch fermentation was carried out using growing cells
under optimal fermentation conditions. The second stage was the production phase, in which ectoine was synthesized and excreted
by phosphate-limited resting cells. Optimal conditions for synthesis and excretion of ectoine during batch fermentation in
a 10 l fermentor were 0.5 mol l−1 NaCl and an initial monosodium glutamate concentration of 80 g l−1 respectively. The pH was adjusted to 7.0 and the temperature was maintained at 33°C. In phosphate-limited resting cells medium,
monosodium glutamate and NaCl concentration was 200 g l−1 and 0.5 mol l−1, respectively, as well as pH was 7.0. The total concentration of ectoine produced was 14.86 g l−1, the productivity and yield of ectoine was 7.75 g l−1 day−1 and 0.14 g g−1, respectively, and the percentage of ectoine excreted was 79%. These levels of ectoine production and excretion are the highest
reported to date. 相似文献
11.
Meiru Li Hongqing Li Xiaoying Hu Xiaoping Pan Guojiang Wu 《Plant Cell, Tissue and Organ Culture》2011,106(3):363-371
Saussurea involucrata is a valuable traditional Chinese medicinal herb. This is the first report of a successful genetic transformation protocol
for S. involucrata using Agrobacterium tumefaciens. Leaf explants were incubated with A. tumefaciens strain EHA105 harboring the binary vector pCAMBIA 1301, which contains the hpt gene as a selectable marker for hygromycin resistance and an intron-containing β-glucuronidase gene as a reporter gene. Following
co-cultivation, about 23.7% of the explants produced hygromycin-resistant calli on MS basal medium (Murashige and Skoog in
Physiol Plant 15: 473–497, 1962) supplemented with 1 mg l−1 benzyladenine (BA), 0.1 mg l−1 α-naphthaleneacetic acid (NAA), 0.1 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D), 20 mg l−1 hygromycin, and 500 mg l−1 cefotaxime. Shoots were regenerated following transfer of the resistant calli to shoot induction medium containing 1.5 mg l−1 BA, 0.1 mg l−1 NAA, 0.25 mg l−1 gibberellic acid (GA3), 20 mg l−1 hygromycin, and 250 mg l−1 cefotaxime, and about 67.5% of the resistant calli differentiated into shoots. Finally, 80% of the hygromycin-resistant shoots
rooted on MS media supplemented with 0.2 mg l−1 NAA, 20 mg l−1 hygromycin, and 250 mg l−1 cefotaxime. The transgenic nature of the transformants was demonstrated by detection of β-glucuronidase activity in the primary
transformants and by Southern blot hybridization analysis. About 16% of the total inoculated leaf explants produced transgenic
plants after approximately 5 months. Using this optimized transformation system, a rice ortholog of the Arabidopsis FLOWERING LOCUS T gene, Hd3a, was transferred into S. involucrata. Introduction of this gene caused an early-flowering phenotype in S. involucrata. 相似文献
12.
Butanol, a four-carbon primary alcohol (C4H10O), is an important industrial chemical and has a good potential to be used as a superior biofuel. Bio-based production of
butanol from renewable feedstock is a promising and sustainable alternative to substitute petroleum-based fuels. Here, we
report the development of a process for butanol production from glycerol, which is abundantly available as a byproduct of
biodiesel production. First, a hyper butanol producing strain of Clostridium pasteurianum was isolated by chemical mutagenesis. The best mutant strain, C. pasteurianum MBEL_GLY2, was able to produce 10.8 g l−1 butanol from 80 g l−1 glycerol as compared to 7.6 g l−1 butanol produced by the parent strain. Next, the process parameters were optimized to maximize butanol production from glycerol.
Under the optimized batch condition, the butanol concentration, yield, and productivity of 17.8 g l−1, 0.30 g g−1, and 0.43 g l−1 h−1 could be achieved. Finally, continuous fermentation of C. pasteurianum MBEL_GLY2 with cell recycling was carried out using glycerol as a major carbon source at several different dilution rates.
The continuous fermentation was run for 710 h without strain degeneration. The acetone–butanol–ethanol productivity and the
butanol productivity of 8.3 and 7.8 g l−1 h−1, respectively, could be achieved at the dilution rate of 0.9 h−1. This study reports continuous production of butanol with reduced byproducts formation from glycerol using C. pasteurianum, and thus could help design a bioprocess for the improved production of butanol. 相似文献
13.
Mashitha Pise Jaishree Rudra Sunita Bundale Deovrat Begde Nandita Nashikkar Avinash Upadhyay 《In vitro cellular & developmental biology. Plant》2012,48(1):85-91
Asparagus racemosus is an important monocot medicinal plant that is in great demand for its steroidal saponins called shatavarins. This study
was initiated to optimize the conditions for production of shatavarins in cell cultures of A. racemosus in a modified Murashige and Skoog (MS) medium supplemented with six different combinations of growth regulators. Biomass
accumulation was correlated with saponin production over a 30-d culture cycle. Biomass and saponin accumulation patterns were
dependent on combinations of growth regulators and the pH of the medium. Maximum levels of saponin and biomass accumulation
were recorded on day 25 of the culture cycle within a pH range of 3.4 to 5.6. Total saponin produced by the in vitro cultures was 20-fold higher than amounts produced by cultivated plants. Saponin accumulation was not a biomass-associated
phenomenon; cultures which showed the highest biomass accumulation were not the highest saponin accumulators. Maximum biomass
(28.30 ± 0.29 g l−1) and maximum levels of shatavarin IV(11.48 ± 0.61 mg g−1) accumulation was found using a medium containing 2.0 mg l−1 2,4-D, 2 g l−1 casein hydrolysate and 0.005% pectinase. The highest levels of sarsapogenin, secreted and intracellular (4.02 ± 0.09 mg g−1), accumulated using a medium containing 1.0 mg l−1 NAA, 1.0 mg l−1 2,4-D, 0.5 mg l−1 BAP, 2 g l−1 casein hydrolysate and 0.005% pectinase, after 25 d. Shatavarins were secreted into the medium and can be isolated easily
for further purification. 相似文献
14.
Bo Long Alex X. Niemiera Zhi-ying Cheng Chun-lin Long 《Plant Cell, Tissue and Organ Culture》2010,101(2):151-162
The effects of seed maturity, media type, carbon source, and organic nutrient additives on seed germination, protocorm development,
and plant growth of Paphiopedilum villosum var. densissimum Z. J. Liu et S. C. Chen were investigated. Micropropagation frequency was enhanced through the use of 200-day-old seed, Knudson
C (KC) medium, and the presence of both glucose and coconut milk in the medium. The effects of various plant growth regulators
on the frequency of shoot organogenesis in four Paphiopedilum species were also investigated. Explants of P. villosum var. densissimum and P. insigne (Lindl.) Stein incubated in the presence of 5 mg l−1 6-benzyladenine (BA) with 0.5 mg l−1 α-naphthalene acetic acid (NAA) and 0.2 mg l−1 BA with 0.1 mg l−1 NAA, respectively, showed a twofold increase in the frequency of shoot organogenesis. For explants of P. bellatulum (Rchb. f.) Stein and P. armeniacum S. C. Chen et F. Y. Liu, the combination of 5.5 mg l−1 BA with 0.5 mg l−1 NAA and 4 mg l−1 BA with 0.1 mg l−1 NAA, respectively, resulted in the highest frequencies of shoot organogenesis. 相似文献
15.
Meiru Li Hongqing Li Xiaoying Hu Xiaoping Pan Guojiang Wu 《Plant Cell, Tissue and Organ Culture》2010,102(3):321-327
Zoysia tenuifolia Willd. ex Trin. is one of the most popularly cultivated turfgrass. This is the first report of successful plant regeneration
and genetic transformation protocols for Z. tenuifolia using Agrobacterium tumefaciens. Initial calli was induced from stem nodes incubated on a Murashige and Skoog (1962) (MS) medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg l−1 6-benzyladenine (BA), with a frequency of 53%. Compact calli were selected and subcultured monthly on the fresh medium. Sixty-nine
percent of the calli could be induced to regenerate plantlets when the calli incubated on a MS medium supplemented with 0.2 mg l−1 BA under darkness. For genetic transformation, calli were incubated with A. tumefaciens strain EHA105 harboring the binary vector pCAMBIA 1301 which contains the hpt gene as a selectable marker for hygromycin resistance and an intron-containing β-glucuronidase gene (gus-int) as a reporter gene. Following co-cultivation, about 12% of the callus explants produced hygromycin resistant calli on
MS medium supplemented with 2 mg l−1 2,4-D, 1 mg l−1 BA, 50 mg l−1 hygromycin, 500 mg l−1 cefotaxime after 8 weeks. Shoots were regenerated following transfer of the resistant calli to shoot induction medium containing
0.2 mg l−1 BA, 50 mg l−1 hygromycin, and 250 mg l−1 cefotaxime, and about 46% of the resistant calli differentiated into shoots. Finally, all the resistant shoots were rooted
on 1/2 MS media supplemented with 50 mg l−1 hygromycin, 250 mg l−1 cefotaxime. The transgenic nature of the transformants was demonstrated by the detection of β-glucuronidase activity in the primary transformants and by PCR and Southern hybridization analysis. About 5% of the total
inoculated callus explants produced transgenic plants after approximately 5 months. The procedure described will be useful
for both, the introduction of desired genes into Z. tenuifolia and the molecular analysis of gene function. 相似文献
16.
A simple protocol for direct shoot organogenesis and plant regeneration in Lessertia frutescens using hypocotyl and cotyledon segments is reported. l-canavanine content in the derived shoots is also quantified. Media containing different concentrations and combinations of
the cytokinins kinetin (K) and benzyladenine (BA) were tested for shoot induction potential. The best shoot regeneration rate
(83%) was obtained from hypocotyl segments cultured in Murashige and Skoog (MS) medium supplemented with 1 mg l−1 K; these hypocotyls also produced the largest number of shoots per explant (3.5) and the longest shoots per explant (13.3
mm). The best shoot regeneration rate (46%) using cotyledons as explant material was obtained in MS medium supplemented with
1 mg l−1 K and 1 mg l−1 BA or with 5 mg l−1 K and 0.5 mg l−1 BA. The highest number of cotyledon-derived shoots (1.5) was obtained in MS medium containing 2 mg l−1 K and 0.5 mg l−1 BA, and the longest cotyledon-derived shoots (6.1 mm) were obtained in MS medium containing 1 mg l−1 K and 0.5 mg l−1 BA. Shoots derived from hypocotyls cultured on media containing 1 mg l−1 K contained the highest quantity of l-canavanine (1.42 mg g−1) relative to the control (0.52 mg g−1). Shoots derived from cotyledons cultured on media containing 2 mg l−1 K contained the highest quantity of l-canavanine (2.07 mg g−1) compared to the control. Scanning electron microscopy revealed that shoots regenerated directly from the wounded epidermal
tissue, although callus formation was observed in most cultures. Young shoot clusters proliferated into healthy adventitious
shoots that were subsequently transferred directly onto rooting medium (MS medium containing 4 mg l−1 indole-3-butyric acid), eliminating the need for an additional multiplication or elongation phase. The in vitro plants were
successfully acclimatized in a growth chamber, achieving an 85% survival rate. 相似文献
17.
Morinda citrifolia adventitious roots were cultured in shake flasks using Murashige and Skoog medium with different types and concentrations
of auxin and cytokinin. Root (fresh weight and dry weight) accumulation was enhanced at 5 mg l−1 indole butyric acid (IBA) and at 7 and 9 mg l−1 naphthalene acetic acid (NAA). On the other hand, 9 mg l−1 NAA decreased the anthraquinone, phenolic and flavonoid contents more severely than 9 mg l−1 IBA. When adventitious roots were treated with kinetin (0.1, 0.3 and 0.5 mg l−1) and thidiazuron (TDZ; 0.1, 0.3 and 0.5 mg l−1) in combination with 5 mg l−1 IBA, fresh weight and dry weight decreased but secondary metabolite content increased. The secondary metabolite content (including
1,1-diphenyl-2-picrylhydrazyl activity) increased more in TDZ-treated than in kinetin-treated roots. Antioxidative enzymes
such as catalase (CAT) and guaiacol peroxidase (G-POD), which play important roles in plant defense, also increased. A strong
decrease in ascorbate peroxidase activity resulted in a high accumulation of hydrogen peroxide. This indicates that adventitious
roots can grow under stress conditions with induced CAT and G-POD activities and higher accumulations of secondary metabolites.
These results suggest that 5 mg l−1 IBA supplementation is useful for growth and secondary metabolite production in adventitious roots of M. citrifolia. 相似文献
18.
Kusampudi Shilpa Chinnasamy Selvakkumar Arun Kumar Senthil Baddireddi Subhadra Lakshmi 《Plant Cell, Tissue and Organ Culture》2010,101(1):105-109
Young leaf explants of Ocimum sanctum L. incubated on solidified Murashige and Skoog (MS) medium supplemented with 2 mg l−1 1-naphthaleneacetic acid (NAA) and 0.2 mg l−1 kinetin (Kn) developed rhizogenic callus. When these were subcultured onto MS medium supplemented with 1.5 mg l−1 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 0.5 mg l−1 NAA, friable rhizogenic callus was observed. Upon transfer of this friable callus onto liquid MS medium containing 4 mg l−1 NAA and 1.3 mg l−1 6-benzyladnine (BA) under continuous agitation at 90 rpm and 16 h photoperiod, roots with an optimum dry weight of 1,460 mg l−1 were obtained. An ethyl acetate extract of these roots exhibited 1, 1–diphenyl-2-picrylhydrazyl (DPPH) radical scavenging
activity. 相似文献
19.
Cellulase production by Aspergillus niger in biofilm, solid-state, and submerged fermentations 总被引:1,自引:0,他引:1
Norma N. Gamarra Gretty K. Villena Marcel Gutiérrez-Correa 《Applied microbiology and biotechnology》2010,87(2):545-551
Cellulase production by Aspergillus niger was compared in three different culture systems: biofilm, solid-state, and submerged fermentation. Biofilm and solid-state
fermentations were carried out on perlite as inert support, and lactose was used as a carbon source in the three culture systems.
In cryo-scanning electron microscopy, biofilm and solid-state cultures gave similar morphological patterns and confirmed that
both spore first attachment and hyphal adhered growth are helped by the production of an adhesive extracellular matrix. Biofilm
cultures produced higher cellulase activities than those in submerged and solid-state cultures (1,768, 1,165, and 1,174 U l−1, respectively). Although biofilm cultures grew less than the other cultures, they produced significantly higher cellulase
yields (370, 212, and 217 U g−1 lactose, respectively) and volumetric productivities (24, 16, and 16 U l−1 h−1, respectively). Likewise, endoglucanase and xylanase activities were higher in biofilm cultures. Under the conditions tested,
it seems that fungal attached growth on perlite may favor better enzyme production. Biofilms are efficient systems for cellulase
production and may replace solid-state fermentation. Biofilm fermentation holds promise for further optimization and development.
The results of this work reveal that fungal biofilms may be used for the commercial production of cellulase employing the
technology developed for submerged fermentation at high cell densities. 相似文献
20.
Thirteen pink-pigmented facultative methylotrophic (PPFM) strains isolated from Adyar and Cooum rivers in Chennai and forest
soil samples in Tamil Nadu, India, along with Methylobacterium extorquens, M. organophilum, M. gregans, and M. komagatae were screened for phosphate solubilization in plates. P-solubilization index of the PPFMs grown on NBRIP—BPB plates for 7 days
ranged from 1.1 to 2.7. The growth of PPFMs in tricalcium phosphate amended media was found directly proportional to the glucose
concentration. Higher phosphate solubilization was observed in four strains MSF 32 (415 mg l−l), MDW 80 (301 mg l−l), M. komagatae (279 mg l−l), and MSF 34 (202 mg l−l), after 7 days of incubation. A drop in the media pH from 6.6 to 3.4 was associated with an increase in titratable acidity.
Acid phosphatase activity was more pronounced in the culture filtrate than alkaline phosphatase activity. Adherence of phosphate
to densely grown bacterial surface was observed under scanning electron microscope after 7-day-old cultures. Biochemical characterization
and screening for methanol dehydrogenase gene (mxaF) confirmed the strains as methylotrophs. The mxaF gene sequence from MSF 32 clustered towards M.
lusitanum sp. with 99% similarity. This study forms the first detailed report on phosphate solubilization by the PPFMs. 相似文献