Effects of gibberellin A(3) on growth and microcystin production in Microcystis aeruginosa (cyanophyta)

Environmental. factors that affect the growth and microcystin production of microcystis have received worldwide attention because of the hazards microcystin poses to environmental safety and public health. Nevertheless, the effects of organic anthropogenic pollution on microcystis are rarely discussed. Gibberellin A(3) (GA(3)) is a vegetable hormone widely used in agriculture and horticulture that can contaminate water as an anthropogenic pollutant. Because of its common occurrence, we studied the effects of GA3 on growth and microcystin production of Microcystis aeruginosa (M. aeruginosa) PCC7806 with different concentrations (0.001-25mg/L) in batch culture. The control was obtained without gibberellin under the same culture conditions. Growth, estimated by dry weight and cell number, increased after the GA3 treatment. GA3 increased the amounts of chlorophyll a, phycocyanin and cellular-soluble protein in the cells of M. aeruginosa PCC7806, but decreased the accumulation of water-soluble carbohydrates. In addition, GA3 was observed to affect nitrogen absorption of the test algae, but to have no effect on the absorption of phosphorus. The amount of microcystin measured by enzyme-Linked immunosorbent assay (ELISA) increased in GA3 treatment groups, but the stimulatory effects were different in different culture phases. It is suggested that GA3 increases M. aeruginosa growth by stimulating its absorbance of nitrogen and increasing its ability to use carbohydrates, accordingly increasing cellular pigments and thus finally inducing accumulation of protein and microcystin. (C) 2007 Elsevier GmbH. All rights reserved.

Simultaneous production of low- and high-frequency sounds by neonatal finless porpoises

Phocoenids are generally considered to be nonwhistling species that produce only high-frequency pulsed sounds. Here our results show that neonatal finless porpoises (Neophocaena phocaenoides) frequently produce clear low-frequency (2-3 kHz) pulsed signals, without distinct high-frequency energy, just after birth and can produce both low- (2-3 kHz) and high-frequency (>100 kHz) pulsed signals simultaneously until about 20 days postnatal. The results indicate that low-frequency signals of neonatal finless porpoises are not an early form of high-frequency signals and suggest that low- and high-frequency signals may be produced by different sound production mechanisms. (C) 2008 Acoustical Society of America.

Kinetic modelling of growth and storage molecule production in microalgae under mixotrophic and autotrophic conditions.

In order to improve algal biofuel production on a commercial-scale, an understanding of algal growth and fuel molecule accumulation is essential. A mathematical model is presented that describes biomass growth and storage molecule (TAG lipid and starch) accumulation in the freshwater microalga Chlorella vulgaris, under mixotrophic and autotrophic conditions. Biomass growth was formulated based on the Droop model, while the storage molecule production was calculated based on the carbon balance within the algal cells incorporating carbon fixation via photosynthesis, organic carbon uptake and functional biomass growth. The model was validated with experimental growth data of C. vulgaris and was found to fit the data well. Sensitivity analysis showed that the model performance was highly sensitive to variations in parameters associated with nutrient factors, photosynthesis and light intensity. The maximum productivity and biomass concentration were achieved under mixotrophic nitrogen sufficient conditions, while the maximum storage content was obtained under mixotrophic nitrogen deficient conditions.

Production planning of multi-stage multi-option seru production systems with sustainable measures

With the concerns over climate change and the escalation in worldwide population, sustainable development attracts more and more attention of academia, policy makers, and businesses in countries. Sustainable manufacturing is an inextricable measure to achieve sustainable development since manufacturing is one of the main energy consumers and greenhouse gas contributors. In the previous researches on production planning of manufacturing systems, environmental factor was rarely considered. This paper investigates the production planning problem under the performance measures of economy and environment with respect to seru production systems, a new manufacturing system praised as Double E (ecology and economy) in Japanese manufacturing industries. We propose a mathematical model with two objectives minimizing carbon dioxide emission and makespan for processing all product types by a seru production system. To solve this mathematical model, we develop an algorithm based on the non-dominated sorting genetic algorithm II. The computation results and analysis of three numeral examples confirm the effectiveness of our proposed algorithm. © 2014 Elsevier Ltd. All rights reserved.

Effects of nonylphenol on the growth and microcystin production of Microcystis strains

Both organic pollution and eutrophication are prominent environmental issues concerning water pollution in the world. It is important to reveal the effects of organic pollutants on algal growth and toxin production for assessing ecological risk of organic pollution. Since nonylphenol (NP) is a kind of persistent organic pollutant with endocrine disruptive effect which exists ubiquitously in environments, NP was selected as test compound in our study to study the relationship between NP stress and Microcystis growth and microcystin production. Our study showed that responses of toxic and nontoxic Microcystis aeruginosa to NP stress were obviously different. The growth inhibition test with NP on M. aeruginosa yielded effect concentrations EbC50 values within this range of 0.67-2.96 mg/L. The nontoxic M. aeruginosa strains were more resistant to NP than toxic strains at concentration above 1 mg/L. Cell growth was enhanced by 0.02-0.2 mg/L NP for both toxic and nontoxic strains, suggesting a hormesis effect of NP on M. aeruginosa. Both toxic and nontoxic strains tended to be smaller with increasing NP. But with the increased duration of the experiment, both the cell size and the growth rate began to resume, suggesting a quick adaptation of M. aeruginosa to adverse stress. NP of 0.05-0.5 mg/L significantly promoted microcystin production of toxic strain PCC7820, suggesting that NP might affect microcystin production of some toxic M. aeruginosa in the field. Our study showed that microcystin excretion was species specific that up to 75% of microcystins in PCC7820 were released into solution, whereas > 99% of microcystins in 562 remained in algal cells after 12 days' incubation. NP also significantly influenced microcystin release into cultural media. The fact that NP enhanced growth and toxin production of M. aeruginosa at low concentrations of 0.02-0.5 mg/L that might be possibly found in natural freshwaters implies that low concentration of NP may favor survival of M. aeruginosa in the field and may play a subtle role in affecting cyanobacterial blooms and microcystin production in natural waters. (c) 2006 Elsevier Inc. All rights reserved.

Kinetic modelling of growth and storage molecule production in microalgae under mixotrophic and autotrophic conditions

In order to improve algal biofuel production on a commercial-scale, an understanding of algal growth and fuel molecule accumulation is essential. A mathematical model is presented that describes biomass growth and storage molecule (TAG lipid and starch) accumulation in the freshwater microalga Chlorella vulgaris, under mixotrophic and autotrophic conditions. Biomass growth was formulated based on the Droop model, while the storage molecule production was calculated based on the carbon balance within the algal cells incorporating carbon fixation via photosynthesis, organic carbon uptake and functional biomass growth. The model was validated with experimental growth data of C. vulgaris and was found to fit the data well. Sensitivity analysis showed that the model performance was highly sensitive to variations in parameters associated with nutrient factors, photosynthesis and light intensity. The maximum productivity and biomass concentration were achieved under mixotrophic nitrogen sufficient conditions, while the maximum storage content was obtained under mixotrophic nitrogen deficient conditions. © 2014 Elsevier Ltd.

Nitrate and phosphate supplementation to increase toxin production by the marine dinoflagellate Alexandrium tamarense

Alexandrium tamarense toxins have great value in biotechnology research as well as important in connection with shellfish poisoning. The influence of nitrate or nitrate and phosphate supplementation on cell biomass and toxin content were investigated in batch cultures. When cultures at low nitrate (88.2 mu M NaNO3) Were supplemented with 793.8 mu M NaNO3 at day 10 the cell density and cellular toxin contents were increased by 6-29% and 20-76%, respectively, compared with controls, and maximal values were 43,600 cells/ml (day 38) and 0.91 pg/cell (day 31). Supplementation with nitrate at day 14 or with nitrate and phosphate at day 10/14 to the cultures did not increase the cell density compared with the non-supplemented middle nitrate or high phosphate (108 mu M NaH2PO4) cultures, respectively, but increased the cellular toxin contents by an average of 52%. The results showed that supplementation with nitrate or with nitrate and phosphate at different growth phases of the cultures increased toxin yield by an average of 46%. Supplementation with nitrate at selected times to maintain continuous low level of nitrate might contribute to the effective increase of toxin yield of A. tamarense. (c) 2005 Elsevier Ltd. All rights reserved.

Thermo-hydro-geomechanical simulations of methane gas production from deep sea methane hydrate formations

A new constitutive model called Methane Hydrate Critical State (MHCS) model was conducted to investigate the geomechanical response of the gas-hydrate-bearing sediments at the Nankai Trough during the wellbore construction process. The strength and dilatancy of gas-hydrate-bearing soil would gradually disappear when the bonds are destroyed because of excessively shearing, which are often observed in dense soils and also in bonded soils such as cemented soil and unsaturated soil. In this study, the MHCS model, which presents such softening features, would be incorporated into a staged-finite-element model in ABAQUS, which mainly considered the loading history of soils and the interaction between cement-casing-formation. This model shows the influence of gas-hydrate-bearing soil to the deformation and stability of a wellbore and the surrounding sediments during wellbore construction. At the same time, the conventional Mohr-Coulomb model was used in the model to show the advantages of MHCS model by comparing the results of the two models.

Estradiol stimulates growth hormone production in female goldfish

The effects of estradiol (E(2)) on growth hormone (GH) production was investigated in gonad-intact female goldfish. It was first necessary to generate a specific antibody for use in immunocytochemistry, Western, and dot-blot analyses of GH production. To accomplish this, grass carp GH (gcGH) cDNA was cloned by the reverse transcription polymerase chain reaction (RT-PCR) and expressed in Echerichia coli and a specific polyclonal antibody to recombinant gcGH was generated in the rabbit. In Western blot, the anti-gcGH antibody specifically immunoreacted with recombinant gcGH, purified natural common carp GH, and with a single 21.5-kDa GH form from pituitary extracts of grass carp, common carp, goldfish, and zebrafish but not salmon, trout, or tilapia. Intraperitoneal injection of the recombinant gcGH enhanced the growth rates of juvenile common carp demonstrating biological activity of this GH preparation. Electron microscopic studies showed that the anti-gcGH-I antibody specifically reacted with GH localized in the secretory granules of the goldfish somatotroph. Using anti-gcGH-I in a dot-blot assay, it was found that in vivo implantation of solid silastic pellets containing E(2) (100 mu g/g body weight for 5 days) increased pituitary GH content by 150% in female goldfish. In a second, independent study employing a previously characterized anticommon carp GH antibody for radioimmunoassay, it was found that E(2) increased pituitary GH content by 170% and serum GH levels by approximately 350%. The E(2)-induced hypersecretion of GH and increase in pituitary GH levels was not associated with changes in steady-state pituitary GH mRNA levels, suggesting that this sex steroid may enhance GH synthesis at the posttranscriptional or translational level. Previous observations indicate that GH can stimulate ovarian E(2) production. The present results show that E(2) can in turn stimulate GH production, indicating the existence of a novel pituitary GH-ovarian feedback system in goldfish. (C) 1997 Academic Press.

Hydrogen production characteristics of the organic fraction of municipal solid wastes by anaerobic mixed culture fermentation

The hydrogen production from the organic fraction of municipal solid waste (OFMSW) by anaerobic mixed culture fermentation was investigated using batch experiments at 37 degrees C. Seven varieties of typical individual components of OFMSW including rice, potato, lettuce, lean meat, oil, fat and banyan leaves were selected to estimate the hydrogen production potential. Experimental results showed that the boiling treated anaerobic sludge was effective mixed inoculum for fermentative hydrogen production from OFMSW. Mechanism of fermentative hydrogen production indicates that, among the OFMSW, carbohydrates is the most optimal substrate for fermentative hydrogen production compared with proteins, lipids and lignocelluloses. This conclusion was also substantiated by experimental results of this study. The hydrogen production potentials of rice, potato and lettuce were 134 mL/g-VS, 106 mL/g-VS, and 50 mL/g-VS respectively. The hydrogen percentages of the total gas produced from rice, potato and lettuce were 57-70%, 41-55% and 37-67%. 2008 International Association for Hydrogen Energy.

Production and characterization of biodiesel from tung oil

The feasibility of biodiesel production from tung oil was investigated. The esterification reaction of the free fatty acids of tung oil was performed using Amberlyst-15. Optimal molar ratio of methanol to oil was determined to be 7.5:1, and Amberlyst-15 was 20.8wt% of oil by response surface methodology. Under these reaction conditions, the acid value of tung oil was reduced to 0.72mg KOH/g. In the range of the molar equivalents of methanol to oil under 5, the esterification was strongly affected by the amount of methanol but not the catalyst. When the molar ratio of methanol to oil was 4.1:1 and Amberlyst-15 was 29.8wt% of the oil, the acid value decreased to 0.85mg KOH/g. After the transesterification reaction of pretreated tung oil, the purity of tung biodiesel was 90.2wt%. The high viscosity of crude tung oil decreased to 9.8mm(2)/s at 40 degrees C. Because of the presence of eleostearic acid, which is a main component of tung oil, the oxidation stability as determined by the Rancimat method was very low, 0.5h, but the cold filter plugging point, -11 degrees C, was good. The distillation process did not improve the fatty acid methyl ester content and the viscosity.

BIODIESEL PRODUCTION FROM DIFFERENT FEEDSTOCKS IN PILOT SCALE SYSTEM

In this study, the preparations of biodiesel from three different feedstocks, including rapeseed oil, high acidified Chinese wood oil and trap grease, were carried out in a pilot scale of 200 t yr(-1) biodiesel production system. The optimum operating conditions for transesterification of rapeseed oil in plug flow reactor were found to be as follows: the catalyst dosage is 1.2 wt%; the retention time is about 17 min; the bed temperature is 65 degrees C; the oil/methanol ratio is 1:6; the content of methyl ester is 96.33% under these conditions. A kind of ion exchange resin, a solid acid catalyst, filled in the fixed bed reactor was used as the esterification catalyst for the pretreating of high acidified oil. The acid value of Chinese wood oil could be reduced from 7 to 0.8 mg KOH.g(-1) after 88 min, the optimum operating conditions were obtained as follow: molar ratio of methanol to oil is about 6:1, the temperature of the fixed bed, 65 degrees C and the retention time, about 88 min. Also a kind of acidified oil, namely trap grease, with the acid value being 114 mg KOH.g(-1) could be equally converted to a good biodiesel product through this system. Generally, the refined biodiesel product generated through this system could meet China #0 Biodiesel Standard, as well as Germany Biodiesel Standard for most indexes. It indicates that the designed process in this system has a good adaptability for different kinds of oil.

Experimental Investigation into the Production Behavior of Methane Hydrate in Porous Sediment with Hot Brine Stimulation

The gas production behavior from methane hydrate in porous sediment by injecting the brine with the salinity of 0−24 wt % and the temperature of −1 to 130 °C was investigated in a one-dimensional experimental apparatus. The results show that the gas production process consists of three periods: the free gas production, the hydrate dissociation, and the general gas reservoir production. The hydrate dissociation accompanies the temperature decrease with the injection of the brine (NaCl solution), and the dissociation duration is shortened with the increase of the salinity. With the injection of hot brine, instantaneous hydrate dissociation rate also increases with the increase of the salinity. However, while the NaCl concentration is beyond a certain value, the rate has no longer continued increasing. Thermal efficiency and energy ratio for the hydrate production can be enhanced by injecting hot brine, and the enhanced effectiveness is quite good with the injection of high salinity at lower temperature.

Optimization of biodiesel production from trap grease via acid catalysis

As a kind of waste collected from restaurants, trap grease is a chemically challenging feedstock for biodiesel production for its high free fatty acid (FFA) content. A central composite design was used to evaluate the effect of methanol quantity, acid concentration and reaction time on the synthesis of biodiesel from the trap grease with 50% free fatty acid, while the reaction temperature was selected at 95 degrees C. Using response surface methodology, a quadratic polynomial equation was obtained for ester content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. To achieve the highest ester content of crude biodiesel (89.67%), the critical values of the three variables were 35.00 (methanol-to-oil molar ratio), 11.27 wt% (catalyst concentration based on trap grease) and 4.59 h (reaction time). The crude biodiesel could be purified by a second distillation to meet the requirement of biodiesel specification of Korea.

Bio-syngas production from biomass catalytic gasification

A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME). Previous studies have studied syngas production from biomass-derived char, oil and gas. This study intends to explore the technology of syngas production from direct biomass gasification, which may be more economically viable. The ratio of H-2/CO is an important factor that affects the performance of this process. In this study, the characteristics of biomass gasification gas, such as H-2/CO and tar yield, as well as its potential for liquid fuel synthesis is explored. A fluidized bed gasifier and a downstream fixed bed are employed as the reactors. Two kinds of catalysts: dolomite and nickel based catalyst are applied, and they are used in the fluidized bed and fixed bed, respectively. The gasifying agent used is an air-steam mixture. The main variables studied are temperature and weight hourly space velocity in the fixed bed reactor. Over the ranges of operating conditions examined, the maximum H-2 content reaches 52.47 vol%, while the ratio of H-2/CO varies between 1.87 and 4.45. The results indicate that an appropriate temperature (750 degrees C for the current study) and more catalyst are favorable for getting a higher H-2/CO ratio. Using a simple first order kinetic model for the overall tar removal reaction, the apparent activation energies and pre-exponential factors are obtained for nickel based catalysts. The results indicate that biomass gasification gas has great potential for liquid fuel synthesis after further processing.