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1.
Julieta Muñoz Armando C. Cahue-López Rodrigo Patiño Daniel Robledo 《Journal of applied phycology》2006,18(2):209-218
The effects of plant growth regulators on callus induction rate and regeneration of K. alvarezii explants was evaluated. K. alvarezii calluses were induced in vitro with kinetin (K), 6-benzylaminopurine (B), 1-naphtalene acetic acid (N) and spermine (S). After 30 days, K. alvarezii explants produced filamentous calluses and isolated crystalline filaments growing from the medullar region and from cortical cells at the cut edge. The plant growth regulators 1-naphtalene acetic acid (1 mg L−1) and 6-benzylaminopurine (1 mg L−1) and the 1-naphtalene acetic acid + kinetin + spermine (1, 1, 0.018 mg L−1 respectively) combination produced 85 to 129% more calluses, with significant differences versus the control (p<0.05). Spermine at 0.018 mg L−1 produced calluses in the apical, intercalary and basal regions of explants. Spermine also reduced callus induction time to 7 days, which is faster than previously reported induction times with other plant growth regulators. An airlift bioreactor was designed and characterized to micropropagate K. alvarezii calluses. The bioreactor had mixing times ranging from 4.6–10.3 s at T
90 and T
95, which is shorter than those for the Fernbach (5.2–13.4 s) and balloon flasks (6.3–17.3 s). Mixing time standard deviations were smaller for the bioreactor (1.1–4.6) than for the Fernbach (9.3–13.6) and balloon flasks (5.5–15.8), suggesting an adequate flow regime within the bioreactor. The results are useful for improving callus induction in K. alvarezii and propagating microplantlets in an airlift bioreactor, and provide baseline data for macroalgal bioreactor culture. 相似文献
2.
Dianne Aster T. Yunque Keneth R. Tibubos Anicia Q. Hurtado Alan T. Critchley 《Journal of applied phycology》2011,23(3):433-438
To improve the production of Kappaphycus plantlets in tissue culture, optimum media concentrations of an Ascophyllum nodosum extract (Acadian Marine Plant Extract Powder, AMPEP), plant growth regulators (PGR), pH–temperature combinations, and explant
density were determined. Kappaphycus alvarezii var. tambalang purple (PUR), kapilaran brown (KAP), vanguard brown (VAN), adik-adik (AA), tungawan green (TGR), and K. striatum var. sacol green (GS) were used as explants. Based on the shortest period for shoot emergence and the economical use of AMPEP, the optimum
enriched media was 3.0 mg L−1 AMPEP and 0.1 mg L−1 AMPEP + PGR 1 mg L−1 each phenylacetic acid (PAA) and zeatin for PUR, 1.0 mg L−1 AMPEP + PGR for KAP and GS, 0.1 mg L−1 AMPEP + PGR for VAN, and 3.0 mg L−1 AMPEP and 0.001 mg L−1 AMPEP + PGR for AA and TGR. Results showed that the addition of PGR to low concentrations of AMPEP hastened shoot formation.
pH–temperature combinations for the most rapid shoot formation were determined for the brown (KAP) and purple (PUR) color
morphotypes of K. alvarezii var. tambalang and the green morphotype of K. striatum var. sacol (GS) cultured in 1.0 mg L−1 AMPEP + PGR. The brown morphotype produced the most number of shoots at pH 7.7 at 20°C after as little as 20 days. Purple
K. alvarezii showed an increased shoot formation at pH 6.7 at 25°C and the green K. striatum morphotype at pH 8.7 at 25°C. The optimum number of explants added to the culture media was also determined for tungawan
green (TGR), brown (KAP), and tambalang purple (PUR) varieties of K. alvarezii in 1.0 mg L−1 AMPEP + PGR. The number of explants and the volume of the culture media combination were also tested. The highest average
number of shoots formed occurred in two explants:1 mL culture media (2:1) for KAP and PUR (35.00% and 16.67%, respectively)
and 1 explant: 2 mL culture media for the TGR (100.00%) with a range of 0.5–3.0 mm shoot length after 40 days in culture.
The earliest shoot formation was observed after 21 days for the brown and 9 days for both the green and purple color morphotypes
of Kappaphycus, in all densities investigated. This indicated that within the range tested, the density of explants did not have a significant
effect on the rate of shoot formation but did influence the average number generated from the culture. The rate of production
of new and improved Kappaphycus explants for a commercial nursery stock was improved through the use of AMPEP with optimized culture media pH, temperature,
and density conditions. 相似文献
3.
Three color morphotypes of Kappaphycus alvarezii var. adik-adik (brown, green and red) collected from a farming area in Tictauan Is., Zamboanga City, Philippines were used as explants
in the study in order to micropropagate ‘new’ plants. Individual sections of sterile Kappaphycus alvarezii var. adik-adik, initially cultured in a 48-well culture plate containing ESS/2 + E3 + PGR, released callus cells after 4–5 days of incubation
at 23–25°C, 13:11H LD cycle and 10–15 μmol photons m−2 s−1 light intensity. True calli were formed after 29–35 days following dense formation of filaments or undifferentiated round
cells at the medullary and inner cortical layers of the section. Plantlets (2–3 mm long) of Kappaphycus alvarezii var. adik-adik were able to regenerate after 98, 150 and 177 days in-vitro among the reds, greens, and browns, respectively. This study established successful methods for the production and regeneration
of tissue explants of Kappaphycus alvarezii var. adik-adik which can possibly be used to mass produce ‘new’ cultivars for land- and sea-based nurseries as sources for commercial farming.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
4.
Simultaneous nutrients and carbon removal during pretreated swine slurry degradation in a tubular biofilm photobioreactor 总被引:1,自引:0,他引:1
Ignacio de Godos Cristina González Eloy Becares Pedro A. García-Encina Raúl Muñoz 《Applied microbiology and biotechnology》2009,82(1):187-194
The biodegradation potential of an innovative enclosed tubular biofilm photobioreactor inoculated with a Chlorella sorokiniana strain and an acclimated activated sludge consortium was evaluated under continuous illumination and increasing pretreated
(centrifuged) swine slurry loading rates. This photobioreactor configuration provided simultaneous and efficient carbon, nitrogen,
and phosphorous treatment in a single-stage process at sustained nitrogen and phosphorous removals efficiencies ranging from
94% to 100% and 70–90%, respectively. Maximum total organic carbon (TOC), NH4
+, and PO4
3− removal rates of 80 ± 5 g C mr
−3 day−1, 89 ± 5 g N mr
−3 day−1, and 13 ± 3 g P mr
−3 day−1, respectively, were recorded at the highest swine slurry loadings (TOC of 1,247 ± 62 mg L−1, N–NH4
+ of 656 ± 37 mg L−1, P–PO4
3+ of 117 ± 19 mg L−1, and 7 days of hydraulic retention time). The unusual substrates diffusional pathways established within the phototrophic
biofilm (photosynthetic O2 and TOC/NH4
+ diffusing from opposite sides of the biofilm) allowed both the occurrence of a simultaneous denitrification/nitrification
process at the highest swine slurry loading rate and the protection of microalgae from any potential inhibitory effect mediated
by the combination of high pH and high NH3 concentrations. In addition, this biofilm-based photobioreactor supported efficient biomass retention (>92% of the biomass
generated during the pretreated swine slurry biodegradation). 相似文献
5.
Griselda Margarita Rodríguez-Figueroa Evgueni Shumilin Ignacio Sánchez-Rodríguez 《Journal of applied phycology》2009,21(1):19-26
The coastal marine sediments near Santa Rosalía on the eastern coast of the Baja California Peninsula (Mexico) are heavily
polluted by metals due to copper mining and smelting over the past century (up to 1984). The present study compares the accumulation
of metals in the brown seaweed Padina durvillaei from the central segment of the coast of Santa Rosalía (polluted by Co, Cu, Mn and Zn) and from two segments north and south
of the known “hot spot”. The seaweed samples were collected in May and August 2004 and June 2005 at 13 stations located along
the Santa Rosalía mining region. Heavy metal concentrations were measured by instrumental neutron activation analysis (Co
and Fe) directly in dried homogenized subsamples or by flame atomic absorption spectrophotometry (Cd, Cu, Mn, Ni, Pb and Zn)
after complete strong acid digestion of sub-samples. The means and standard deviations of the concentrations in dry tissues
of Padina durvillaei specimens for all the studied metals and stations lie in the following sequence: Cd (3.6 ± 1.6 mg kg−1) < Co (6.5 ± 6.1 mg kg−1) < Pb (7.8 ± 6.2) < Ni (9.96 ± 5.28 mg kg−1) < Cu (53 ± 38 mg kg−1) < Zn (63 ± 43 mg kg−1) < Mn (295 ± 269 mg kg−1) < Fe (2243 ± 2325 mg kg−1). This increase of the average concentrations was statistically significant. Principal Component Analysis showed that Factor
1 (36.46%) displays high positive loadings for Co, Cu, Mn and Zn, reflecting the influence of local anthropogenic pollution
on the seaweed composition, while Factor 2 (26.91%) is important for Co, Fe and Ni and probably corresponds to the adsorption
or accumulation of terrigenous elements of the regional origin, while Factor 3, with a high positive loading for Pb and a
high negative loading for Cd, is probably controlled by local and regional anthropogenic input of Pb and episodic supply of
Cd by local upwellings. The results of ANOVA for each element do not show any significant differences between the average
concentrations for Cd, Fe, Ni and Pb in the seaweed of the three segments, or between the central and southern segments for
Cu, Mn and Zn. Cobalt contents in the seaweed from the northern and central segments are, however, significantly different
from the southern segment. This indicates that element concentrations in Padina durvillaei generally do not follow the drastic increases and gradients of Cu, Co, Mn and Zn contents detected in surface sediments.
The apparent contradiction could be explained by a low geochemical mobility of these metals in the polluted sediments, composed
mainly of stable residues of smelter wastes, with very low content of organic matter usually driving diagenetic mobilization
of some metals into interstitial waters and then to the overlying water. 相似文献
6.
To screen stimulators from Chinese medicinal insects for mycelial growth and polysaccharides production of Ganoderma lucidum, G. lucidum was inoculated into the media with and without supplementation of medicinal insect extracts. The ethyl acetate extract of
Eupolyphaga sinensis at 55 mg l−1 lead to significant increase in both biomass and intracellular polysaccharides (IPS) concentration from 8.53 ± 0.41 to 14.16 ± 0.43
and 1.28 ± 0.09 to 2.13 ± 0.11 g l−1, respectively. In addition, the ethyl acetate extract of Catharsius molossus at 55 mg l−1 significantly enhanced extracellular polysaccharides (EPS) production; the EPS yield increased from 350.9 ± 14.1 to 475.1 ± 15.3 mg
l−1. There were no new components in the two types of polysaccharides obtained by the addition of the insect extracts. 相似文献
7.
Use of Acadian marine plant extract powder from Ascophyllum nodosum in tissue culture of Kappaphycus varieties 总被引:1,自引:0,他引:1
Anicia Q. Hurtado Dianne Aster Yunque Keneth Tibubos Alan T. Critchley 《Journal of applied phycology》2009,21(6):633-639
Three varieties of Kappaphycus alvarezii (Kapilaran, KAP), Tambalang purple (PUR), Adik-adik (AA), and one variety of Kappaphycus striatum var. sacol (green sacol (GS) were used to determine the efficiency of Acadian marine plant extract powder (AMPEP) as a culture medium
at different concentrations, for the regeneration of young plants of Kappaphycus varieties, using tissue culture techniques for the production of seed stock for nursery and outplanting purposes for the
commercial cultivation of carrageenophytes. A shorter duration for shoot formation was observed when the explant was treated
with AMPEP + Plant Growth Regulator (PGR = PAA + zeatin at 1 mg L−1) compared to AMPEP when used singly. However, four explants responded differently to the number of days required for shoot
formation. The KAP variety took 46 days to form shoots at 3–4 mg L−1 AMPEP + PGR; while PUR required 21 days at 3–5 mg L−1 AMPEP and 3–4 mg L−1 AMPEP + PGR. AA required 17 days at 3–5 mg L−1 AMPEP and AMPEP + PGR; and GS 25 days at 1 mg L−1 AMPEP + PGR. It was observed that among the four explants used, PUR and AA initiated shoot formation with the use of AMPEP
only at higher concentrations (3–5 mg L−1) after a shorter period. Only PUR responded positively to ESS/2 for shoot initiation. The use of AMPEP alone and/or in combination
with PGR as a culture medium in the propagation of microplantlets using tissue culture technique is highly encouraging. 相似文献
8.
Katarzyna Paraszkiewicz Aleksandra Frycie Mirosława Słaba Jerzy Długoński 《Biometals》2007,20(5):797-805
The influence of cadmium, zinc and lead on fungal emulsifier synthesis and on the growth of filamentous fungus Curvularia lunata has been studied. Tolerance to heavy metals established for C. lunata was additionally compared with the sensitivity exhibited by strains of Curvularia tuberculata and Paecilomyces marquandii—fungi which do not secrete compounds of emulsifying activity. Although C. lunata, as the only one out of all studied fungi, exhibited the lowest tolerance to heavy metals when grown on a solid medium (in
conditions preventing emulsifier synthesis), it manifested the highest tolerance in liquid culture - in conditions allowing
exopolymer production. Cadmium, zinc and lead presented in liquid medium up to a concentration of 15 mM had no negative effect
on C. lunata growth and stimulated emulsifier synthesis. In the presence of 15 mM of heavy metals, both the emulsifier and 24-h-old growing
mycelium exhibited maximum sorption capacities, which were determined as 18.2 ± 2.67, 156.1 ± 10.32 mg g−1 for Cd2+, 22.2 ± 3.40, 95.2 ± 14.21 mg g−1 for Zn2+ and 51.1 ± 1.85, 230.0 ± 28.47 mg g−1 for Pb2+ respectively. The results obtained by us in this work indicate that the emulsifier acts as a protective compound increasing
the ability of C. lunata to survive in heavy metal polluted environment. Enhancement of exopolymer synthesis in the presence of Cd2+, Zn2+ and Pb2+ may also suggest, at least to some extent, a metal-specific nature of emulsifier production in C. lunata. Due to accumulation capability and tolerance to heavy metals, C. lunata mycelium surrounded by the emulsifier could be applied for toxic metal removal. 相似文献
9.
Le Dinh Hung Kanji Hori Huynh Quang Nang Tran Kha Le Thi Hoa 《Journal of applied phycology》2009,21(3):265-272
The three color morphotypes of the red alga Kappaphycus alvarezii (brown, red and green) were cultured in Camranh Bay, Vietnam, using the fixed off-bottom monoline culture method to evaluate
the growth rate, carrageenan yield, 3,6-anhydrogalactose, gel strength and lectin content. The brown morphotype was cultivated
over a 12-month period; the red and green morphotypes were over a 6-month period. At the 60-day culture timepoint, the brown
morphotype showed a higher growth rate (3.5–4.6% day−1) from September to February, and lower growth rate (1.6–2.8% day−1) from March to August. Significant (P < 0.05) differences in growth rate between culture months were found with the brown morphotype. High growth rates for the
red (3.6–4.4% day−1) and green (3.7–4.2% day−1) morphotypes were obtained from September to February. The carrageenan yield, 3,6-anhydrogalactose and gel strength of the
three morphotypes showed little variation, with the highest values obtained in November–December. At the 30-day sampling point,
the brown morphotype had a higher lectin content (167–302 μg g−1 dry alga) from August to March and a lower lectin content (23–104 μg g−1 dry alga) from April to July. High lectin contents were recorded for the red (139–338 μg g−1 dry alga) and green (124–259 μg g−1 dry alga) morphotypes from September to February. This study shows that the different morphotypes of K. alvarezii can be grown in the tropical waters of the Camranh during the northeast monsoon, and part of the southwest monsoon, especially
the brown morphotype, which can be grown during any season. 相似文献
10.
The influence of toluene concentration on the specific growth rate, cellular yield, specific CO2, and metabolite production by Pseudomonas putida F1 (PpF1) was investigated. Both cellular yield and specific CO2 production remained constant at 1.0 ± 0.1 g biomass dry weight (DW) g−1 toluene and 1.91 ± 0.31 g CO2 g−1 biomass, respectively, under the tested range of concentrations (2–250 mg toluene l−1). The specific growth rate increased up to 70 mg toluene l−1. Further increases in toluene concentration inhibited PpF1 growth, although inhibitory concentrations were far from the application range of biological treatment processes. The specific
ATP content increased with toluene concentration up to toluene concentrations of 170 mg l−1. 3-Methyl catechol (3-MC) was never detected in the cultivation medium despite being an intermediary in the TOD pathway.
This suggested that the transformation from toluene to 3-MC was the limiting step in the biodegradation process. On the other
hand, benzyl alcohol (BA) was produced from toluene in a side chain reaction. This is, to the best of our knowledge, the first
reported case of methyl monoxygenation of toluene by PpF1 not harboring the pWW0 TOL plasmid. In addition, the influence of 3-MC, BA, and o-cresol on toluene degradation was investigated respirometrically, showing that toluene-associated respiration was not significantly
inhibited in the presence of 10–100 mg l−1 of the above-mentioned compounds. 相似文献
11.
T Roukas 《Journal of industrial microbiology & biotechnology》1999,22(6):617-621
Aureobasidium pullulans P56 was investigated using an adaptation technique and a mixed culture system. The adaptation of A. pullulans and the mixed cultures of A. pullulans and/or Lactobacillus brevisX20, Debaryomyces hansenii 194 and Aspergillus niger did not increase the production of polysaccharide. Enzymic hydrolysis of lactose in deproteinized whey gave a higher polysaccharide
concentration and polysaccharide yield than acidic hydrolysed lactose. Maximum polysaccharide concentration (11.0 ± 0.5 g L−1), biomass dry weight (10.5 ± 0.4 g L−1), polysaccharide yield (47.2 ± 1.8%) and sugar utilization (93.2 ± 2.8%) were achieved using enzyme-hydrolysed whey (pH 6.5)
containing 25 g L−1 lactose and supplemented with K2HPO4 0.5%, L-glutamic acid 1%, olive oil 2.5%, and Tween 80 0.5%. In this case the pullulan content of the crude polysaccharide was 40%.
Received 16 December 1997/ Accepted in revised form 12 March 1999 相似文献
12.
Phytoplankton biomass and productivity were measured during two cruises in the Bransfield Strait in December 1991 (D91) and
January/February 1993 (J93). Strong seasonal variability in productivity values was observed due to differences in the physiological
response of phytoplankton. However, although the photosynthetic capacity of phytoplankton was markedly lower in D91 [P
m
B
=0.61 ± 0.25 mg C (mg Chla)−1 h−1] than in J93 [P
m
B
=2.18 ± 0.91 mg C (mg Chla)−1 h−1], average water column chlorophyll values in different areas of the strait were approximately similar in D91 (49–78 mg Chla
m−2) and J93 (22–76 mg Chla m−2). The spatial distribution of chlorophyll was patchy and generally associated with the influence of the different water masses
that meet together in the Bransfield Strait. No correlation was found between the mixed layer depth and either the integrated
chlorophyll or the productivity. Our results suggest that major phytoplankton blooms in the Bransfield Strait are advected
from the nearby Gerlache Strait or Bellingshausen Sea following the main eastward surface currents.
Accepted: 5 July 1998 相似文献
13.
Chitwadee Phithakrotchanakoon Ratama Daduang Arinthip Thamchaipenet Thidarat Wangkam Toemsak Srikhirin Lily Eurwilaichitr Verawat Champreda 《Applied microbiology and biotechnology》2009,82(1):131-140
A polyhydroxyalkanote depolymerase gene from Thermobifida sp. isolate BCC23166 was cloned and expressed as a C-terminal His6-tagged fusion in Pichia pastoris. Primary structure analysis revealed that the enzyme PhaZ-Th is a member of a proposed new subgroup of SCL-PHA depolymerase
containing a proline–serine repeat linker. PhaZ-Th was expressed as two glycosylated forms with apparent molecular weights
of 61 and 70 kDa, respectively. The enzyme showed esterase activity toward p-nitrophenyl alkanotes with V
max and K
m of 3.63 ± 0.16 μmol min−1 mg−1 and 0.79 ± 0.12 mM, respectively, on p-nitrophenyl butyrate with optimal activity at 50–55°C and pH 7–8. Surface plasmon resonance (SPR) analysis demonstrated that
PhaZ-Th catalyzed the degradation of poly-[(R)-3-hydroxybutyrate] (PHB) films, which was accelerated in (R)-3-hydroxyvalerate copolymers with a maximum degradation rate of 882 ng cm−2 h−1 for poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (12 mol% V). Surface deterioration, especially on the amorphous regions of PHB films
was observed after exposure to PhaZ-Th by atomic force microscopy. The use of P. pastoris as an alternative recombinant system for bioplastic degrading enzymes in secreted form and a sensitive SPR analytical technique
will be of utility for further study of bioplastic degradation. 相似文献
14.
This study was aimed at determining the optimal depth and photon irradiance for growth of Sargassum fulvellum. Sampling and measurement of underwater irradiance were carried out at farms cultivating S. fulvellum at Wando, southwestern coast of Korea, from May 2004 to April 2005. Growth of thalli, underwater irradiance and photosynthetic
quantum yield were measured over a range of depths for three culture stages. During their nursery cultivation stage (Stage
I), length increase was greatest at 1.5 m depth (2.5 ± 0.2 cm), where the average midday irradiance over 28 days was 488 ± 58
μmol photons m−2 s−1. During the pre-main cultivation stage (Stage II), the greatest length increase occurred at 1 m depth (10.9 ± 0.1 cm) with
an average irradiance of 845 ± 169 μmol photons m−2 s−1. For the main cultivation stage (Stage III) of the alga, thalli showed maximal length growth in March and early April at
depths of 1–2 m and 3 m. These results suggest that growth at each cultivation stage of S. fulvellum could be controlled by depth of cultivation rope.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
15.
Production of hexanoic acid from d-galactitol by a newly isolated Clostridium sp. BS-1 总被引:1,自引:0,他引:1
Byoung Seung Jeon Byung-Chun Kim Youngsoon Um Byoung-In Sang 《Applied microbiology and biotechnology》2010,88(5):1161-1167
In a study screening anaerobic microbes utilizing d-galactitol as a fermentable carbon source, four bacterial strains were isolated from an enrichment culture producing H2, ethanol, butanol, acetic acid, butyric acid, and hexanoic acid. Among these isolates, strain BS-1 produced hexanoic acid
as a major metabolic product of anaerobic fermentation with d-galactitol. Strain BS-1 belonged to the genus Clostridium based on phylogenetic analysis using 16S rRNA gene sequences, and the most closely related strain was Clostridium sporosphaeroides DSM 1294T, with 94.4% 16S rRNA gene similarity. In batch cultures, Clostridium sp. BS-1 produced 550 ± 31 mL L−1 of H2, 0.36 ± 0.01 g L−1 of acetic acid, 0.44 ± 0.01 g L−1 of butyric acid, and 0.98 ± 0.03 g L−1 of hexanoic acid in a 4-day cultivation. The production of hexanoic acid increased to 1.22 and 1.73 g L−1 with the addition of 1.5 g L−1 of sodium acetate and 100 mM 2-(N-morpholino)ethanesulfonic acid (MES), respectively. Especially when 1.5 g L−1 of sodium acetate and 100 mM MES were added simultaneously, the production of hexanoic acid increased up to 2.99 g L−1. Without adding sodium acetate, 2.75 g L−1 of hexanoic acid production from d-galactitol was achieved using a coculture of Clostridium sp. BS-1 and one of the isolates, Clostridium sp. BS-7, in the presence of 100 mM MES. In addition, volatile fatty acid (VFA) production by Clostridium sp. BS-1 from d-galactitol and d-glucose was enhanced when a more reduced culture redox potential (CRP) was applied via addition of Na2S·9H2O. 相似文献
16.
Takashi Nemoto Taisuke Watanabe Yutaka Mizogami Jun-ichi Maruyama Katsuhiko Kitamoto 《Applied microbiology and biotechnology》2009,82(6):1105-1114
The recombinant Pichia pastoris harboring an improved methionine adenosyltransferase (MAT) shuffled gene was employed to biosynthesize S-adenosyl-l-methionine (SAM). Two l-methionine (l-Met) addition strategies were used to supply the precursor: the batch addition strategy (l-Met was added separately at three time points) and the continuous feeding strategies (l-Met was fed continuously at the rate of 0.1, 0.2, and 0.5 g l−1 h−1, respectively). SAM accumulation, l-Met conversion rate, and SAM productivity with the continuous feeding strategies were all improved over the batch addition
strategy, which reached 8.46 ± 0.31 g l−1, 41.7 ± 1.4%, and 0.18 ± 0.01 g l−1 h−1 with the best continuous feeding strategy (0.2 g l−1 h−1), respectively. The bottleneck for SAM production with the low l-Met feeding rate (0.1 g L−1 h−1) was the insufficient l-Met supply. The analysis of the key enzyme activities indicated that the tricarboxylic acid cycle and glycolytic pathway
were reduced with the increasing l-Met feeding rate, which decreased the adenosine triphosphate (ATP) synthesis. The MAT activity also decreased as the l-Met feeding rate rose. The reduced ATP synthesis and MAT activity were probably the reason for the low SAM accumulation when
the l-Met feeding rate reached 0.5 g l−1 h−1. 相似文献
17.
Rafael Rodrigues Loureiro Renata Perpetuo Reis Alan T. Critchley 《Journal of applied phycology》2010,22(1):101-104
Diseases such as “ice-ice” and “goose bumps” are responsible for loss of almost 70% of infected Kappaphycus production. To improve the growth of K. alvarezii and reduce the impact of diseases, the effect of the commercial Ascophyllum nodosum extract was tested. Five grams of apical branches of each K. alvarezii variant (n = 6) were bathed at different extract concentrations (e.g., 5, 10, 15, 20, 25, and 30 g L−1) for 1 hour. To test the effect of the extract on epiphytes apical tips were not cleaned. After 2 weeks, the epiphytes such
as Cladophora sp. and Ulva sp. disappeared. Polysiphonia subtilissima survived but its appearance was weak. The highest K. alvarezii growth rates were observed at extract concentrations of 15 and 20 g L−1 (p < 0.001), almost double the expected for a 45-day production cycle used at Sepetiba Bay, Brazil. These results show that
the extract was efficient at improving the growth of K. alvarezii and reducing the presence of some epiphytes. 相似文献
18.
The commercial cultivation of Kappaphycus alvarezii is the main source of raw material for the carrageenan industry. Brazilian commercial farming uses floating rafts that serve
as substrata for fouling organisms that may affect production of the carrageenophyte seedlings. The aim of this work was to
identify and quantify the biofouling on floating rafts at Sepetiba Bay, Rio de Janeiro State (23° 02′ 25″ S and 43° 53′ 39″
W), and to evaluate seedling damage caused by epibionts and endobionts. Samples were collected from August 2006 to August
2007. In each assessment, organisms contained in random sampling areas of 18 quadrats of 0.10 m2 (n = 18) were removed from floating rafts. K. alvarezii seedling samples were collected to verify the presence of epibionts or endobionts (n = 30). Twenty-four taxa belonging to seven groups of animals and three groups of seaweed were found. The percentage occurrence estimated 13 dominant
organisms and amphipod tubes: e.g., Chondracanthus tedii, Cladophora vagabunda, Gracilariopsis tenuifrons, Hypnea spinella, Hypnea musciformis, Hincksia mitchelliae, Spyridia spp., Ulva spp., Bowerbankia sp., Bugula neritina, Botryllus sp., Haplosclerida sp., and Perna perna. Richness, equitability, diversity, and total biomass varied significantly during the study period (p < 0.001). There was a tendency for higher biomass values in August 2007. After 6 months, epibionts (i.e., Chlorophyta, Rhodophyta,
Chordata, Cnidaria and Ectoprocta) were found on K. alvarezii seedlings. Endobionts were not found in this study. The biofouling biomass was not found to have a significant effect on
K. alvarezii daily growth rate, carrageenan yield, or quality (gel strength and viscosity; p > 0.05). 相似文献
19.
Mannan Hajimahmoodi Mohammad Ali Faramarzi Najmeh Mohammadi Neda Soltani Mohammad Reza Oveisi Nastaran Nafissi-Varcheh 《Journal of applied phycology》2010,22(1):43-50
Antioxidant activities of both cells and extracellular substances were evaluated in 12 soil-isolated strains of microalgae
according to FRAP and DPPH-HPLC assays. Their total phenolic contents were also determined by Folin–Ciocalteu method. Extractions
were performed with hexane, ethyl acetate, and water. The results of FRAP assay showed that algal cells contained considerable
amounts of antioxidants from 0.56 ± 0.06 to 31.06 ± 4.00 μmol Trolox g−1 for Microchaete tenera hexane extract and Chlorella vulgaris water extract, respectively. In water fractions of extracellular substances, the antioxidants were from 1.30 ± 0.15 μmol
Trolox g−1 for Fischerella musicola to 73.20 ± 0.16 μmol Trolox g−1 for Fischerella ambigua. Also, DPPH-HPLC assay represented high antioxidant potential of water fractions. The measured radical-scavenging activities
of the studied microalgae were at least 0.15 ± 0.02 in Nostoc ellipsosporum cell mass to a maximum of 109.02 ± 8.25 in C. vulgaris extracellular substance. The amount of total phenolic contents varied in different strains of microalgae and ranged from
zero in hexane extract to 19.15 ± 0.04 mg GAE g−1 in C. vulgaris extracellular water fraction. Significant correlation coefficients between two measured parameters indicated that phenolic
compounds were a major contributor to the microalgal antioxidant capacities. 相似文献
20.
Ribitsch D Karl W Wehrschütz-Sigl E Tutz S Remler P Weber HJ Gruber K Stehr R Bessler C Hoven N Sauter K Maurer KH Schwab H 《Applied microbiology and biotechnology》2009,81(5):875-886
In the course of a microbial screening of soil samples for new oxidases, different enrichment strategies were carried out.
With choline as the only carbon source, a microorganism was isolated and identified as Arthrobacter nicotianae. From this strain, a gene coding for a choline oxidase was isolated from chromosomal DNA. This gene named codA was cloned in Escherichia coli BL21-Gold and the protein (An_CodA) heterologously overexpressed as a soluble intracellular protein of 59.1 kDa. Basic biochemical characterization of
purified protein revealed a pH optimum of 7.4 and activity over a broad temperature range (15–70 °C). Specific activities
were determined toward choline chloride (4.70 ± 0.12 U/mg) and the synthetic analogs bis(2-hydroxyethyl)-dimethylammonium
chloride (0.05 ± 0.45 × 10–2 U/mg) and tris-(2-hydroxyethyl)-methylammonium methylsulfate (0.01 ± 0.12 × 10–2 U/mg). With increasing number of oxidizable groups, a significant decrease in activity was noted. Determination of kinetic
parameters in atmorspheric oxygen resulted in K
M = 1.51 ± 0.09 mM and V
max = 42.73 ± 0.42 mU/min for choline chloride and K
M = 4.77 ± 0.76 mM and V
max = 48.40 ± 2.88 mU/min for the reaction intermediate betaine aldehyde respectively. Nuclear magnetic resonance spectroscopic
analysis of the products formed during the enzyme reaction with choline chloride showed that in vitro the intermediate betaine
aldehyde exists also free in solution. 相似文献