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1.
Effect of Substrate Concentration on Dark Fermentation Hydrogen Production Using an Anaerobic Fluidized Bed Reactor 总被引:1,自引:0,他引:1
The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces
hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from
1 to 8 h and an influent glucose concentration from 2 to 25 g L−1. The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 °C with an
influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 g L−1 showed satisfactory H2 production performance, but the reactor fed with 25 g L−1 of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 g L−1 when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of
1 h and a feed strength of 10 g L−1. The AFBRs operated with glucose concentrations of 2 and 4 g L−1 produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount
of solvents. 相似文献
2.
Chairattanamanokorn P Tapananont S Detjaroen S Sangkhatim J Anurakpongsatorn P Sirirote P 《Applied biochemistry and biotechnology》2012,166(2):389-401
Dark anaerobic fermentation is an interesting alternative method for producing biohydrogen (H2) as a renewable fuel because of its low cost and various usable organic substrates. Pulping sludge from wastewater treatment
containing plentiful cellulosic substrate could be feasibly utilized for H2 production by dark fermentation. The objective of this study was to investigate the optimal proportion of pulping sludge
to paper waste, the optimal initial pH, and the optimal ratio of carbon and nitrogen (C/N) for H2 production by anaerobic seed sludge pretreated with heat. The pulping sludge was pretreated with NaOH solution at high temperature
and further hydrolyzed with crude cellulase. Pretreatment of the pulping sludge with 3% NaOH solution under autoclave at 121 °C
for 2 h, hydrolysis with 5 FPU crude cellulase at 50 °C, and pH 4.8 for 24 h provided the highest reducing sugar production
yield (229.68 ± 2.09 mg/gTVS). An initial pH of 6 and a C/N ratio of 40 were optimal conditions for H2 production. Moreover, the supplement of paper waste in the pulping sludge enhanced the cumulative H2 production yield. The continuous hydrogen production was further conducted in a glass reactor with nylon pieces as supporting
media and the maximum hydrogen production yield was 151.70 ml/gTVS. 相似文献
3.
Wanwisa Moon-ai Ploypat Niyomploy Ruethairat Boonsombat Polkit Sangvanich Aphichart Karnchanatat 《Applied biochemistry and biotechnology》2012,166(8):2138-2155
Superoxide dismutase (SOD, EC 1.15.1.1) is a metalloenzyme or antioxidant enzyme that catalyzes the disproportionation of
the harmful superoxide anionic radical to hydrogen peroxide and molecular oxygen. Due to its antioxidative effects, SOD has
long been applied in medicinal treatment, cosmetic, and other chemical industries. Fifteen Zingiberaceae plants were tested
for SOD activity in their rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Curcuma aeruginosa were found to contain a significant level of SOD activity. The SOD enzyme was enriched 16.7-fold by sequential ammonium sulfate
precipitation, diethylaminoethyl cellulose ion exchange, and Superdex 75 gel filtration column chromatography. An overall
SOD yield of 2.51 % with a specific activity of 812.20 U/mg was obtained. The enriched SOD had an apparent MW of 31.5 kDa,
as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and a pH and temperature optima of 4.0 and 50 °C.
With nitroblue tetrazolium and riboflavin as substrates, the K
m values were 57.31 ± 0.012 and 1.51 ± 0.014 M, respectively, with corresponding V
max values of 333.7 ± 0.034 and 254.1 ± 0.022 μmol min−1 mg protein−1. This SOD likely belongs to the Fe- or Mn-SOD category due to the fact that it was insensitive to potassium cyanide or hydrogen
peroxide inhibition, but was potentially weakly stimulated by hydrogen peroxide, and stimulated by Mn2+and Fe2+ ions. Moreover, this purified SOD also exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production
in cultured mouse macrophage cell RAW 264.7 in a dose-dependent manner (IC50 = 14.36 ± 0.15 μg protein/ml). 相似文献
4.
The alterations of organic acids citrate, α-ketoglutarate, succinate, fumarate, malate production together with isocitrate
lyase activity as a glyoxalate shunt enzyme, and antibiotic production of Streptomyces sp M4018 were investigated in relation to changes in the glucose, glycerol and starch concentrations (5–20 g/L) after identification
as a strain of Streptomyces hiroshimensis based on phenotypic and genotypic characteristics. The highest intracellular citrate and α-ketoglutarate levels in 20 g/l
of glucose, glycerol, and starch mediums were 399.47 ± 4.78, 426.93 ± 6.40, 355.84 ± 5.38 ppm and 444.81 ± 5.12, 192.96 ± 2.26,
115.20 ± 2.87 ppm, respectively. The highest succinate, malate, and fumarate levels were also determined in 20 g/l of glucose
medium as 548.9 ± 11.21, 596.15 ± 8.26, and 406.42 ± 6.59 ppm and the levels were significantly higher than the levels in
glycerol and starch. Extracellular organic acid levels measured also showed significant correlation with carbon source concentrations
by showing negative correlation with pH levels of the growth medium. The antibiotic production of Streptomyces sp. M4018 was also higher in glucose medium as was the case also for organic acids when compared with glycerol. On the other
hand, there is no production in starch. 相似文献
5.
Sensitive fluorescent probes for determination of hydrogen peroxide and glucose based on enzyme-immobilized magnetite/silica nanoparticles 总被引:2,自引:0,他引:2
Qing Chang Lihua Zhu Guodong Jiang Heqing Tang 《Analytical and bioanalytical chemistry》2009,395(7):2377-2385
Sensitive fluorescent probes for the determination of hydrogen peroxide and glucose were developed by immobilizing enzyme
horseradish peroxidase (HRP) on Fe3O4/SiO2 magnetic core–shell nanoparticles in the presence of glutaraldehyde. Besides its excellent catalytic activity, the immobilized
enzyme could be easily and completely recovered by a magnetic separation, and the recovered HRP-immobilized Fe3O4/SiO2 nanoparticles were able to be used repeatedly as catalysts without deactivation. The HRP-immobilized nanoparticles were able
to activate hydrogen peroxide (H2O2), which oxidized non-fluorescent 3-(4-hydroxyphenyl)propionic acid to a fluorescent product with an emission maximum at 409 nm.
Under optimized conditions, a linear calibration curve was obtained over the H2O2 concentrations ranging from 5.0 × 10−9 to 1.0 × 10−5 mol L−1, with a detection limit of 2.1 × 10−9 mol L−1. By simultaneously using glucose oxidase and HRP-immobilized Fe3O4/SiO2 nanoparticles, a sensitive and selective analytical method for the glucose detection was established. The fluorescence intensity
of the product responded well linearly to glucose concentration in the range from 5.0 × 10−8 to 5.0 × 10−5 mol L−1 with a detection limit of 1.8 × 10−8 mol L−1. The proposed method was successfully applied for the determination of glucose in human serum sample. 相似文献
6.
H. K. Ahn M. C. Smith S. L. Kondrad J. W. White 《Applied biochemistry and biotechnology》2010,160(4):965-975
Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application with
reduced environmental impacts. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion
[>15% total solid (TS)] has an advantage over wet digestion (<10% TS) because it allows for the use of a smaller volume of
reactor and because it reduces wastewater production. In addition, it produces a fertilizer that is easier to transport. Performance
of anaerobic digestion of animal manure–switchgrass mixture was evaluated under dry (15% TS) and thermophilic conditions (55 °C).
Three different mixtures of animal manure (swine, poultry, and dairy) and switchgrass were digested using batch-operated 1-L
reactors. The swine manure test units showed 52.9% volatile solids (VS) removal during the 62-day trial, while dairy and poultry
manure test units showed 9.3% and 20.2%, respectively. Over the 62 day digestion, the swine manure test units yielded the
highest amount of methane 0.337 L CH4 /g VS, while the dairy and poultry manure test units showed very poor methane yield 0.028 L CH4/g VS and 0.002 L CH4/g VS, respectively. Although dairy and poultry manure performed poorly, they may still have high potential as biomass for
dry anaerobic digestion if appropriate designs are developed to prevent significant volatile fatty acid (VFA) accumulation
and pH drop. 相似文献
7.
Yanhua Li Kelong Huang Dongming Zeng Suqin Liu Zufu Yao 《Journal of Solid State Electrochemistry》2010,14(7):1205-1211
RuO2/Co3O4 thin films with different RuO2 content were successfully prepared on fluorine-doped tin oxide coated glass plate substrates by spray pyrolysis method, and
their capacitive behavior was investigated. Electrochemical property was performed by cyclic voltammetry, constant current
charge/discharge, and electrochemical impedance spectra. The capacitive performance of RuO2/Co3O4 thin films with different RuO2 content corresponded to a contribution from a main pseudocapacitance and an additional electric double-layer capacitance.
The specific capacitance of pure Co3O4, 15.5%, 35.6%, and 62.3% RuO2 composites at the current density of 0.2 A g−1 were 394 ± 8, 453 ± 9, 520 ± 10, and 690 ± 14 F g−1, respectively; 62.3% RuO2 composite presented the highest specific capacitance value at various current densities, whereas 35.6% RuO2 composite exhibited not only the largest specific capacitance contribution from RuO2 (C
sp
RuO2) at the current density of 0.5, 1.0, 1.5, and 2.0 A g−1 but also the highest specific capacitance retention ratio (46.3 ± 2.8%) at the current density ranging from 0.2 to 2.0 A g−1. Electrochemical impedance spectra showed that the contact resistance dropped gradually with the decrease of RuO2 content, and the charge-transfer resistance (R
ct) increased gradually with the decrease of RuO2 content. 相似文献
8.
An effective protocol was developed for in vitro regeneration of the Cassia angustifolia via indirect organogenesis from petiole explants excised from 21-day-old axenic seedlings. Organogenic callus were induced
on Murashige and Skoog (MS) medium supplemented with 5.0 μM 2,4-dichlorophenoxy acetic acid and 2.5 μM thidiazuron (TDZ).
Adventitious shoot regeneration was achieved on MS medium supplemented with 5.0 μM TDZ as it induced 8.5 ± 0.98 shoots in
85% cultures. The number of shoots and shoot length was significantly enhanced when cultures were subcultured on auxin–cytokinin-containing
medium. The highest number of shoots (12.5 ± 1.10) and shoot length (4.3 ± 0.20 cm) was recorded on MS medium supplemented
with 5.0 μM TDZ and 1.5 μM indole-3-acetic acid. Regenerated shoots were rooted best on MS medium supplemented with 10.0 μM
indole-3-butyric acid followed by their transfer to liquid MS filter paper bridge medium. The plants were successfully hardened
off in sterile soilrite followed by their establishment in garden soil with 70% survival rate. The plants showed normal morphological
characteristics similar to the field grown plants. 相似文献
9.
A phosphite dehydrogenase gene (ptdhK) consisting of 1,011-bp nucleotides which encoding a peptide of 336 amino acid residues was cloned from Pseudomonas sp. K. gene ptdhK was expressed in Escherichia coli BL21 (DE3) and the corresponding recombinant enzyme was purified by metal affinity chromatography. The recombinant protein
is a homodimer with a monomeric molecular mass of 37.2 kDa. The specific activity of PTDH-K was 3.49 U mg−1 at 25 °C. The recombinant PTDH-K exhibited maximum activity at pH 3.0 and at 40 °C and displayed high stability within a
wide range of pHs (5.0 to 10.5). PTDH-K had a high affinity to its natural substrates, with K
m values for sodium phosphite and NAD of 0.475 ± 0.073 and 0.022 ± 0.007 mM, respectively. The activity of PTDH-K was enhanced
by Na+, NH4+, Mg2+, Fe2+, Fe3+, Co2+, and EDTA, and PTDH-K exhibited different tolerance to various organic solvents. 相似文献
10.
Ming-Zhou Zhang Min-Zi Wang Zong-Lun Chen Jie-Hong Fang Mei-Ming Fang Jun Liu Xiao-Ping Yu 《Analytical and bioanalytical chemistry》2009,395(8):2591-2599
A multianalyte lateral-flow immunochromatographic technique using colloidal gold-labeled polyclonal antibodies was developed
for the rapid simultaneous detection of clenbuterol and ractopamine. The assay procedure could be accomplished within 5 min,
and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not.
When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the test strip under an optical density scanner were calculated to be 0.1 ± 0.01 ng mL−1 and 0.1 ± 0.01 ng mL−1, 0.56 ± 0.08 ng mL−1, and 0.71 ± 0.06 ng mL−1, respectively, the cut-off levels with the naked eye of 1 ng mL−1 and 1 ng mL−1 for clenbuterol and ractopamine were observed. Parallel analysis of swine urine samples with clenbuterol and ractopamine
showed comparable results obtained from the multianalyte lateral-flow test strip and GC-MS. Therefore, the described multianalyte
lateral-flow test strip can be used as a reliable, rapid, and cost-effective on-site screening technique for the simultaneous
determination of clenbuterol and ractopamine residues in swine urine.
相似文献
11.
Biogas Production from Anaerobic Co-digestion of Food Waste with Dairy Manure in a Two-Phase Digestion System 总被引:2,自引:0,他引:2
Co-digestion of food waste and dairy manure in a two-phase digestion system was conducted in laboratory scale. Four influents
of R0, R1, R2, and R3 were tested, which were made by mixing food waste with dairy manure at different ratios of 0:1, 1:1,
3:1, and 6:1, respectively. For each influent, three runs of experiments were performed with the same overall hydraulic retention
time (HRT) of 13 days but different HRT for acidification (1, 2, and 3 days) and methanogenesis (12, 11, and 10 days) in two-phase
digesters. The results showed that the gas production rate (GPR) of co-digestion of food waste with dairy manure was enhanced
by 0.8–5.5 times as compared to the digestion with dairy manure alone. Appropriate HRT for acidification was mainly determined
by the biodegradability of the substrate digested. Three-, 2-, and 1-day HRT for acidification were found to be optimal for
the digestion of R0, R1, and R2/R3, respectively, when overall HRT of 13 days was used. The highest GPR of 3.97 L/L·day was
achieved for R3(6:1) in Run 1 (1 + 12 days), therefore, the mixing ratio of 6:1 and HRT of 1 day for acidification were considered
to be the optimal ones and thus recommended for co-digestion of food waste and dairy manure. There were close correlations
between degradation of organic matters and GPR. The highest VS removal rate was achieved at the same HRT for acidification
and mixing ratio of food waste and dairy manure as GPR in the co-digestion. The two-phase digestion system showed good stability,
which was mainly attributed to the strong buffering capacity with two-phase system and the high alkalinity from dairy manure
when co-digested with food waste. 相似文献
12.
Maneerat Yodjun Aphichart Karnchanatat Polkit Sangvanich 《Applied biochemistry and biotechnology》2012,166(8):2037-2050
Ammonium sulphate cut protein extracts, and their pepsin hydrolysates, from the rhizomes of 15 plants in the Zingiberaceae
family were screened for their in vitro angiotensin I-converting enzyme inhibitory (ACEI) activity. The protein extract from
Zingiber ottensii had the highest ACEI activity (IC50 of 7.30 × 10−7 mg protein/mL) and was enriched for by SP Sepharose chromatography with five NaCl step gradients 0, 0.25, 0.50, 0.75 and
1 M NaCl collecting the corresponding five fractions. The highest ACEI activity was found in the F75 fraction, which appeared
to contain a single 20.7-kDa protein, suggesting enrichment to or near to homogeneity. The ACEI activity of the F75 fraction
was moderately thermostable (−20–60 °C), showed >80% activity across a broad pH range of 4–12 (optimal at pH 4–5) and appeared
as a competitive inhibitor of ACE (K
i of 9.1 × 10−5 mg protein/mL). For the pepsin hydrolysates, that from Zingiber cassumunar revealed the highest ACEI activity (IC50 of 0.38 ± 0.012 mg/mL), was enriched to a single active hexapeptide by RP-HPLC with a strong ACEI activity (IC50 of 0.011 ± 0.012 mg/mL) and acted as a competitive inhibitor of ACE (K
i of 1.25 × 10−6 mg protein/mL). 相似文献
13.
Joana P. N. Ribeiro Luís M. Magalhães Marcela A. Segundo Salette Reis José L. F. C. Lima 《Analytical and bioanalytical chemistry》2010,397(7):3005-3014
In the present work, a fluorimetric automatic method based on multisyringe flow injection analysis (MSFIA) was developed for
in vitro evaluation of scavenging capacity against nitric oxide (NO) using 4,5-diaminofluorescein (DAF-2) as an NO-selective
fluorogenic probe. The MSFIA manifold was assembled to perform the in-line generation of NO and the competitive reaction of
putative scavenger molecules and DAF-2 with NO at conditions close to those found in vivo regarding temperature (37°C), pH
(7.4), and concentration of NO (less than 1 μM). This approach allowed the evaluation of scavenging capacity against NO by
endogenous antioxidant molecules, pharmaceutical compounds, and human plasma. IC50 values were calculated for rutin (1.30 ± 0.02 μM, positive control), cysteine (321 ± 8 μM), reduced glutathione (1106 ± 93 μM),
uric acid (134 ± 12 μM), dipyrone (1.36 ± 0.06 μM), and captopril (363 ± 28 μM). A high degree of automation was attained
as the successive dilution of antioxidant standard solutions required for IC50 assessment was performed automatically, in a dilution chamber placed in the flow system. A determination throughput of 16 h-1 and a good precision were attained (relative standard deviation between 1.6 and 9.0%), fostering the application of the proposed
method to routine/screening analysis of scavenging capacity against NO. 相似文献
14.
Costa D Fernandes E Santos JL Pinto DC Silva AM Lima JL 《Analytical and bioanalytical chemistry》2007,387(6):2071-2081
In the present study, a new fluorescence microplate screening assay for evaluating scavenging activity against singlet oxygen
(1O2) was implemented. The chemical generation of 1O2 was promoted using the thermodissociable endoperoxide of disodium 3,3′-(1,4-naphthalene)bispropionate (NDPO2). The detection of 1O2 was achieved using dihydrorhodamine 123 (DHR), a nonfluorescent molecule that is oxidizable to the fluorescent form rhodamine
123 (RH). The combined use of a 1O2-selective generator and a highly sensitive probe (DHR) was then successfully applied to perform a screening assay of the
1O2 scavenging activities of ascorbic acid, penicillamine, cysteine, N-acetylcysteine (NAC), methionine, reduced glutathione (GSH), dihydrolipoic acid, lipoic acid, and sodium azide. All of these
antioxidants exhibited concentration-dependent 1O2 scavenging capacities. They could be ranked according to observed activity: ascorbic acid> cysteine> penicillamine> dihydrolipoic
acid > GSH> NAC> sodium azide> lipoic acid (IC50 values of 3.0 ± 0.2, 8.0 ± 0.7, 10.9 ± 0.8, 25.2 ± 4.5, 57.4 ± 5.9, 138 ± 13, 1124 ± 128, 2775 ± 359 μM, mean±SEM, respectively)
> methionine (35% of scavenging effect at 10 mM). In conclusion, the use of NDPO2 as a selective generator for 1O2 and its fluorescence detection by the highly sensitive probe DHR is shown to be a reliable and resourceful analytical alternative
means to implement a microplate screening assay for scavenging activity against 1O2.
Generation and detection of singlet oxygen 相似文献
15.
Valiollah Babaeipour Seyed Abbas Shojaosadati Rasoul Khalilzadeh Nader Maghsoudi Amir Mohammad Farnoud 《Applied biochemistry and biotechnology》2010,160(8):2366-2376
Development of inexpensive and simple culture media and appropriate induction conditions are always favorable for industry.
In this research, chemical composition and stoichiometric data for γ-interferon production and recombinant Escherichia coli growth were used in order to achieve a simple medium and favorable induction conditions. To achieve this goal, the effects
of medium composition and induction conditions on the production of γ-interferon were investigated in batch culture of E. coli BL21 (DE3) [pET3a-ifnγ]. These conditions were considered as suitable conditions for the production of γ-interferon: 2.5× M9 medium, supplemented
with a mixture of amino acids (milligram per liter), including glutamic acid 215, aspartic acid 250, lysine 160, and phenylalanine
90, and induction at late-log phase (OD600 = 4.5). Under these conditions, dry cell weight of 6 ± 0.2 g/l and γ-interferon concentration of 2.15 ± 0.1 g/l were obtained.
Later, without changing the concentration ratio of amino acids and glucose, the effect of increase in the primary glucose
concentration on productivity of γ-interferon was investigated. It was found that 25 g/l glucose will result in maximum attainable
biomass and recombinant human γ-interferon. At improved conditions, a dry cell weight of 14 ± 0.2 g/l, concentration and overall
productivity of γ-interferon 4.2 ± 0.1 g/l and 420 ± 10 mg/l h, respectively, were obtained. 相似文献
16.
Yi Wang Jian Zhao Jian-He Xu Li-Qiang Fan Su-Xia Li Li-Li Zhao Xiao-Bo Mao 《Applied biochemistry and biotechnology》2010,162(8):2387-2399
A lipase gene from Serratia marcescens ECU1010 was cloned into expression vector pET28a, sequenced, and overexpressed as an N terminus His-tag fusion protein in
Escherichia coli. Through the optimization of culture conditions in shake flask, the lipase activity was improved up to 1.09 × 105 U/l, which is a great improvement compared to our previous reports. It was purified to homogeneity by Ni-NTA affinity chromatography
with an overall yield of 59.4% and a purification factor of 2.4-fold. This recombinant lipase displayed excellent stability
below 30 °C and within the pH range of 5.0−6.8, giving temperature and pH optima at 40 °C and pH 9.0, respectively. The lipase
activity was found to increase in the presence of metal ions such as Ca2+, Cu2+, and some nonionic surfactants such as PEG series. In addition, among p-nitrophenyl esters of fatty acids with varied chain length, the recombinant lipase showed the maximum activity on p-nitrophenyl laurate (C12). Using racemic trans-3-(4′-methoxy-phenyl)-glycidyl methyl ester [(±)-MPGM] as substrate, which is a key chiral synthon for production of diltiazem,
a 50% conversion yield was achieved after 4 h in toluene–water (100 mM KPB phosphate buffer, pH 7.5) biphasic system (5:5 ml)
at 30 °C under shaking condition (160 rpm), affording (−)-MPGM in nearly 100% ee. The K
m and V
max values of the lipase for (±)-MPGM were 222 mM and 1.24 mmol min−1 mg−1, respectively. The above-mentioned features make the highly enantioselective lipase from Serratia marcescens ECU1010 a robust biocatalyst for practical use in large-scale production of diltiazem intermediate. 相似文献
17.
Vivekanand V Dwivedi P Pareek N Singh RP 《Applied biochemistry and biotechnology》2011,165(1):204-220
In solid-state fermentation, among various solid supports evaluated, banana peel was found to be an ideal support and resulted
into higher levels of laccase (6281.4 ± 63.60 U l−1) along with notable levels of manganese peroxidase production (1339.0 ± 131.23 U l−1) by Aspergillus fumigatus VkJ2.4.5. Maximum levels of laccase was achieved under derived conditions consisting of 80% of moisture level, 6 days of
incubation period, 6% inoculum level, and an aeration level of 2.5 l min−1. A column-tray bioreactor was designed to scale up and economize the enzyme production in three successive cycles of fermentation
using the same fungal biomass. Thermal and pH stability profiles revealed that enzyme was stable up to 50°C and at varying
pH range from 5–9 for up to 2 h. The apparent molecular weight of laccase was found to be 34 ± 1 kDa. MALDI-TOF/TOF analysis
of the protein showed significant homology with maximum identity of 67% to other laccases reported in database. 相似文献
18.
Assamoi Allah Antoine Destain Jacqueline Philippe Thonart 《Applied biochemistry and biotechnology》2010,160(1):50-62
There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past
few decades. Their application in the field of fermentation technology has resulted in the production of bulk chemicals and
value-added products such as amino acid, enzymes, mushroom, organic acids, single-cell protein, biologically active secondary
metabolites, etc. (Ramachandran et al., Bioresource Technology 98:2000–2009, 2007). In this work, the production of extracellular xylanase by the fungus Penicillium canescens was investigated in solid-state fermentation using five agro-industrial substrates (soya oil cake, soya meal, wheat bran,
whole wheat bran, and pulp beet). The best substrate was the soya oil cake. In order to optimize the production, the most
effective cultivation conditions were investigated in Erlenmeyer flasks and in plastic bags with 5 and 100 g of soya oil cake,
respectively. The initial moisture content, initial pH, and temperature of the culture affected the xylanase synthesis. The
optimal fermentation medium was composed by soya oil cake crushed to 5 mm supplemented with 3% and 4% (w/w) of casein peptone and Na2HPO4.2H2O. After 7 days of incubation at 30 °C and under 80% of initial moisture, a xylanase production level of 18,895 ± 778 U/g
(Erlenmeyer flasks) and 9,300 ± 589 U/g (plastic bags) was reached. The partially purified enzyme recovered by ammonium sulfate
fractionation was completely stable at freezing and refrigeration temperatures up to 6 months and reasonably stable at room
temperature for more than 3 months. 相似文献
19.
Minakata K Nozawa H Gonmori K Yamagishi I Suzuki M Hasegawa K Watanabe K Suzuki O 《Analytical and bioanalytical chemistry》2011,400(7):1945-1951
An electrospray ionization tandem mass spectrometric (ESI-MS-MS) method has been developed for the determination of cyanide
(CN–) in blood. Five microliters of blood was hemolyzed with 50 μL of water, then 5 μL of 1 M tetramethylammonium hydroxide solution
was added to raise the pH of the hemolysate and to liberate CN– from methemoglobin. CN– was then reacted with NaAuCl4 to produce dicyanogold, Au(CN)2–, that was extracted with 75 μL of methyl isobutyl ketone. Ten microliters of the extract was injected directly into an ESI-MS-MS
instrument and quantification of CN– was performed by selected reaction monitoring of the product ion CN– at m/z 26, derived from the precursor ion Au(CN)2– at m/z 249. CN– could be measured in the quantification range of 2.60 to 260 μg/L with the limit of detection at 0.56 μg/L in blood. This
method was applied to the analysis of clinical samples and the concentrations of CN– in the blood were as follows: 7.13 ± 2.41 μg/L for six healthy non-smokers, 3.08 ± 1.12 μg/L for six CO gas victims, 730 ± 867 μg
for 21 house fire victims, and 3,030 ± 97 μg/L for a victim who ingested NaCN. The increase of CN– in the blood of a victim who ingested NaN3 was confirmed using MS-MS for the first time, and the concentrations of CN– in the blood, gastric content and urine were 78.5 ± 5.5, 11.8 ± 0.5, and 11.4 ± 0.8 μg/L, respectively. 相似文献
20.
In order to reduce of the manufacturing cost of bacterial cellulose (BC), BC production by Acetobacter sp. V6 was investigated in shaking culture using molasses and corn steep liquor (CSL) as the sole carbon and nitrogen sources,
respectively. The highest BC production was obtained with Ca3(PO4)2-treated molasses. Maximum BC yield (2.21 ± 0.04 g/l) was obtained at 5% (w/v) total sugar in molasses. In improved medium containing molasses and CSL, BC production was observed in the medium after
1 day of incubation and increased rapidly thereafter with maximum yield (3.12 ± 0.03 g/l) at 8 days. This value was approximately
twofold higher than the yield in the complex medium. Physical properties of BC from the complex and molasses media were studied
using Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffractometer. By FT-IR, all the BC were found to be of cellulose
type І, the same as typical native cellulose. The relative crystallinity of BC produced in the complex and molasses media
were 83.02 and 67.27%, respectively. These results suggest that molasses and CSL can be useful low-cost substrates for BC
production by Acetobacter sp. V6 without supplementation with expensive nitrogen complexes such as yeast extract and polypeptone, leading to the reduction
in the production costs. 相似文献