Granular activated carbon single-chamber microbial fuel cells (GAC-SCMFCs): A design suitable for large-scale wastewater treatment processes

As an emerging biotechnology capable of removing contaminants and producing electricity, microbial fuel cells (MFCs) hold a promising future in wastewater treatment. However, several main problems, including the high internal resistance (R_in), low power output, expensive material, and complicated configuration have severely hindered the large-scale application of MFCs. The study targeted these challenges by developing a novel MFC system, granular activated carbon single-chamber MFC, termed as GAC-SCMFC. The batch tests showed that GAC was a good substitute for carbon cloth and GAC-SCMFCs generated high and stable power outputs compared with the traditional two-chamber MFCs (2CMFCs). Critical operational parameters (i.e. wastewater substrate concentrations, GAC amount, electrode distance) affecting the performance of GAC-SCMFCs were examined at different levels. The results showed that the R_in gradually decreased from 60 Ω to 45 Ω and the power output increased from 0.2 W/m³ to 1.2 W/m³ when the substrate concentrations increased from 100 mg/L to 850 mg/L. However, at high concentrations of 1000–1500 mg/L, the power output leveled off. The R_in of MFCs decreased 50% when the electrode distance was reduced from 7.5 cm to 1 cm. The highest power was achieved at the electrode distance of 2 cm. The power generation increased with more GAC being added in MFCs due to the higher amount of biomass attached. Finally, the multi-anode GAC-SCMFCs were developed to effectively collect the electrons generated in the GAC bed. The results showed that the current was split among the multiple anodes, and the cathode was the limiting factor in the power production of GAC-SCMFCs.     

Evaluation and enhanced operational performance of microbial fuel cells under alternating anodic open circuit and closed circuit modes with different substrates

The present study evaluates the performance of air-cathode microbial fuel cells (MFCs) under alternating open circuit/closed circuit (OC/CC) modes and its effect on independent-electrode and full-cell potentials, power output (at different external resistances) and the polarization behaviour of the electrodes. Three different types of feeds were evaluated using this approach: (1) phosphorus buffer solution (PBS) with acetate as carbon source, (2) glucose-rich synthetic wastewater, and (3) sewage from wastewater treatment plant enriched with fermented molasses. When MFCs were suddenly switched to CC from OC and then again back to OC from CC, the behaviour of the anodes vs reference electrode (Ag/AgCl, 3 M KCl) was monitored. When electric circuit of the MFCs was switched from open to closed circuit, for all cases: (a) the anode potential-shift (vs Ag/AgCl) reallocated in the positive direction in about 200–400 mV, (b) the air-cathode potential-shift (vs Ag/AgCl) reallocated in the negative direction in about 10–25 mV, and (c) the cell-potential difference started at around 0 mV and progressively increased as the MFC reached stability. This behaviour was consistently reproduced during different OC/CC cycles. The systems studied delivered good performance with both controlled media and industrial wastewater. Additionally, this study provides insightful characterization of the independent-electrode behaviours.     

Simultaneous nitrogen and carbon removal in a single chamber microbial fuel cell with a rotating biocathode

In this study, a single chamber microbial fuel cell (MFC) with a rotating biocathode is developed to simultaneously remove chemical oxygen demand (COD) and nitrogen accompanying current production. Under continuous regime with a feeding COD/N ratio of 5:1, removal efficiencies of total organic carbon (TOC) and total nitrogen (TN) were 85.7 ± 7.4% and 91.5 ± 7.2%, respectively, and a maximum power output of 585 mW m^?3 was yielded. In the batch tests, TN removal efficiencies for closed/open circuit were 82.1 ± 0.5% and 59.4 ± 3.3%, respectively. Cyclic voltammetry measurements demonstrated that the biocathode could efficiently catalyze nitrate reduction reaction. Autotrophic denitrification facilitated nitrogen removal using the electrode as electron donor. 16S rRNA-denaturing gradient gel electrophoresis (DGGE) was employed for community fingerprinting. At the biocathode the bacteria involved in nitrogen cycle predominated, of which the denitrifying bacteria were closely similar to Acidovorax sp. and/or Delftia sp. They were affiliated with the family Comamondaceae. The combination of rotating biological contactors with MFCs derives a promising opportunity for wastewater treatment with a low cost and high quality effluent.     

The effect of internal capacitance on power quality and energy efficiency in a tubular microbial fuel cell

The pseudo-capacitive behaviour of a high surface area carbon veil electrode in a tubular microbial fuel cell (MFC) was investigated as a mechanism to enhance power quality and energy efficiency. Accumulated charge and energy from the anodic biofilm after prolonged open circuit times (1–120 min) were compared against equivalent periods of steady state loading (R = 100–3000 Ω). A significant difference in the amount of accumulated charge with different loads was observed, resulting in 1.051 C (R = 100 Ω) compared to 0.006 C (R = 3 kΩ). The automated application of short open and closed circuit (0.5–10 s) cycles resulted in an increase of power/current production (closed circuit alone), but presented lower efficiency considering entire open and closed period. The cumulative charge on the carbon veil electrode with biofilm was 39,807 C m⁻² at 100 Ω. Electrochemical Impedance Spectroscopy (EIS) showed that the Helmholtz layer presented a double layer capacitance of more than ten times the biofilm on electrode. The results indicate that the capacitive behaviour could be utilized to increase the power quality, i.e. its availability/applicability with respect to the operation of low power consuming devices.     

Weak electric fields serve as guidance cues that direct retinal ganglion cell axons in vitro

Growing axons are directed by an extracellular electric field in a process known as galvanotropism. The electric field is a predominant guidance cue directing retinal ganglion cell (RGC) axons to the future optic disc during embryonic development. Specifically, the axons of newborn RGCs grow along the extracellular voltage gradient that exists endogenously in the embryonic retina (Yamashita, 2013 [8]). To investigate the molecular mechanisms underlying galvanotropic behaviour, the quantification of the electric effect on axon orientation must be examined. In the present study, a culture system was built to apply a constant, uniform direct current (DC) electric field by supplying an electrical current to the culture medium, and this system also continuously recorded the voltage difference between the two points in the medium. A negative feedback circuit was designed to regulate the supplied current to maintain the voltage difference at the desired value. A chick embryo retinal strip was placed between the two points and cultured for 24 h in an electric field in the opposite direction to the endogenous field, and growing axons were fluorescently labelled for live cell imaging (calcein-AM). The strength of the exogenous field varied from 0.0005 mV/mm to 10.0 mV/mm. The results showed that RGC axons grew in the reverse direction towards the cathode at voltage gradients of ≥0.0005 mV/mm, and straightforward extensions were found in fields of ≥0.2–0.5 mV/mm, which were far weaker than the endogenous voltage gradient (15 mV/mm). These findings suggest that the endogenous electric field is sufficient to guide RGC axons in vivo.     

Current and voltage responses in instant photosynthetic microbial cells with Spirulina platensis

The electrical response of photosynthetic microbial cells (PMCs) containing Spirulina platensis was investigated to assess the feasibility of using these PMCs as instant-use and portable devices. The PMCs were constructed without membranes, mediators, or any additive organic substrates. Once S. platensis was attached to an anode, voltage was instantly obtained and ready for application. Since no additional substrate was required as fuel for electricity generation, these PMCs were different from typical microbial fuel cells. PMCs were examined under various operating conditions, and they performed under high open circuit voltage (OCV) with high power output in the dark, short electrode spacing (2 cm), low pH value (5.5), and high temperature (40 °C) conditions. According to Ohm's Law and the Nernst equation, the superior OCV and power output were caused by high ionic strength, low internal resistance, and high temperature. Additionally, two equal-sized PMCs were arranged in serial and parallel configurations. The former yielded higher voltage while the latter yielded higher current density.     

Microfiltration membrane performance in two-chamber microbial fuel cells

Proton exchange membranes (PEMs) are typically used in two-chamber microbial fuel cells (MFCs) to separate the anode and cathode chambers while allowing protons to pass between the chambers. However, PEMs such as Nafion are not cost-effective. To reduce the cost of MFCs, we examined the performances of cellulose acetate microfiltration membranes in a two-chamber microbial fuel cell using acetate. The internal resistance, the maximum power density and the coulombic efficiency (CE) of the microfiltration membrane MFC (MMMFC) were 263 Ω, 0.831 ± 0.016 W/m² and 38.5 ± 3.5%, respectively, in a fed-batch mode, while the corresponding values of the MFC using a PEM were 267 Ω, 0.872 ± 0.021 W/m² and 74.7 ± 4.6%, respectively. We further used the MMMFC for poultry wastewater treatment. The maximum power density of 0.746 ± 0.024 W/m² and CE of 35.3 ± 3.2% were achieved when the poultry wastewater containing 566 mg/L COD was used, removing 81.6 ± 6.6% of the COD. These results demonstrate microfiltration membranes, compared with PEMs, have a similar internal resistance and reduce pH gradient across the membrane. They parallel PEMs in maximum power density, while CE is much lower due to the oxygen and substrate diffusion. The MMMFC was effective for poultry wastewater treatment with high COD removal.     

Essential oil composition of Senecio graciliflorus DC: Comparative analysis of different parts and evaluation of antioxidant and cytotoxic activities

The essential oil of different parts of Senecio graciliflorus DC was obtained by hydrodistillation and analysed by GC-FID and GC–MS for the first time. A total of 17, 20, 19 and 17 constituents were identified comprising 99.90, 95.50, 98.93 and 95.96% of the essential oil of flower, leaf, stem and root parts of Senecio graciliflorus respectively. Monoterpene hydrocarbons predominated in the essential oil with 85.28% in flower, 57.53% in leaf, 67.74% in stem and 64.98% in root oil. α-pinene, cis-ocimene, 1,2,3-trimethylcyclohexane and β-pinene were the major constituents of the essential oil. The flower essential oil exhibited a strong antioxidant potential displaying IC₅₀ values of 21.6 ± 0.6 and 26.0 ± 1.0 μg/ml in DPPH and hydroxyl radical assays respectively. On the other hand the essential oil of flower and root displayed highest cytotoxicity against lung (A-549) cancer cell lines (IC₅₀ = 19.1 ± 0.9 and 21.3 ± 1.1 μg/ml respectively. This study which represents the first report of the essential oil composition and bioevaluation of Senecio graciliflorus, can serve as a new source of cytotoxic and antioxidant activity.     

Evaluation of Pseudomonas syringae strain ESC-11 for biocontrol of crown rot and anthracnose of banana

Pseudomonas syringae strain ESC-11 and 250 μg/ml each of thiabendazole (TBZ) and imazalil reduced crown rot of banana caused by Fusarium aff. sacchari by 30–36% and 83–86%, respectively, in laboratory experiments. Four field trials performed in Costa Rica varied in treatment combinations. In field trials 1 and 2, 125 and 250 μg/ml each of TBZ and imazalil + 0.5% or 1% alum (aluminum ammonium sulfate) and ESC-11, and 250 μg/ml each of TBZ and imazalil + 1% alum reduced rot and mold. ESC-11 alone or with 0.5% alum significantly reduced rot and mold in field trial 2. In trial 3, 50 and 100 μg/ml of TBZ alone and with ESC-11 reduced mold. In trial 4, 125 μg/ml each of TBZ and imazalil and ESC-11, and 300 μg/ml each of TBZ and imazalil reduced rot, and 50 and 125 μg/ml each of TBZ and imazalil and ESC-11, and 300 μg/ml each of TBZ and imazalil reduced mold. In three field trials, there was no significant difference among treatments for latex staining. In field trial 2 only, combinations of TBZ, imazalil, and alum with or without ESC-11, reduced anthracnose, caused by Colletotrichum musae. The complex of crown rot fungi, order of treatment application, effect of alum and fungicides on ESC-11, concentration of ESC-11, and level of disease may contribute to the variation in crown rot and anthracnose control by ESC-11. Though ESC-11 alone was not effective in reducing disease, further testing in combination with low rates of fungicide should be done.     

The use of a mirror reduces isolation stress in horses being transported by trailer

Horse trailers are a common form of transportation for horses and ponies and often require the animal to travel alone or with a single companion. The current study investigated the effect of transporting horses alone, in company or with an acrylic safety mirror (measuring 81 cm × 61.5 cm) that provided surrogate companionship. The behavioural and physiological responses of 12 mature horses during a 30-min journey by trailer under the three treatments were compared. Behaviours (vocalisation, eating, head-tossing, pawing, and head-turning) were recorded. In order to assess circulatory changes that occur as part of the response to transport, heart rate (HR), rectal (T_r) and ear-pinna (T_p) temperatures were recorded. When travelling with a live companion significantly less time was spent vocalising (p < 0.001), head-turning (p < 0.001), head-tossing (p < 0.01) and pawing (p < 0.01); eating behaviour increased (p < 0.05). Physiological responses (increases in HR and T_r and decreases in T_p) were also significantly reduced when travelling with a live companion (p < 0.01). Travelling with the mirror did not significantly affect physiological responses compared with travelling alone, but the rise in T_r and fall in T_p was reduced (p = 0.052 and p = 0.051, respectively) and can be considered a trend. When travelling with a mirror significantly less time was spent turning the head (p < 0.01), vocalising (p < 0.05) and head-tossing (p < 0.05); eating behaviour increased (p < 0.05). The only significant difference between travelling with a live companion and a mirror was that the time spent turning the head round was less with a live companion (p < 0.05). The provision of surrogate companionship in the form of a mirror was found to be preferable to travel alone, but where possible a live companion is recommended. Isolation during transportation was found to suppress feeding behaviour. Although peripheral blood flow (T_p) has been used to assess transport stress in other species it has not previously been used in the horse. Further evaluation of this non-invasive measure is now required.     

Vitamin D sufficiency associates with an increase in anti-inflammatory cytokines after intense exercise in humans

The purpose of this study was to identify the influence of vitamin D status (insufficient vs. sufficient) on circulating cytokines and skeletal muscle strength after muscular injury. To induce muscular injury, one randomly selected leg (SSC) performed exercise consisting of repetitive eccentric–concentric contractions. The other leg served as the control. An averaged serum 25(OH)D concentration from two blood samples collected before exercise and on separate occasions was used to establish vitamin D insufficiency (<30 ng/mL, n = 6) and sufficiency (>30 ng/mL, n = 7) in young, adult males. Serum cytokine concentrations, single-leg peak isometric force, and single-leg peak power output were measured before and during the days following the exercise protocol. The serum IL-10 and IL-13 responses to muscular injury were significantly (both p < 0.05) increased in the vitamin D sufficient group. The immediate and persistent (days) peak isometric force (p < 0.05) and peak power output (p < 0.05) deficits in the SSC leg after the exercise protocol were not ameliorated with vitamin D sufficiency. We conclude that vitamin D sufficiency increases the anti-inflammatory cytokine response to muscular injury.     

Isolation and bioelectrochemical characterization of novel fungal sources with oxidasic activity applied in situ for the cathodic oxygen reduction in microbial fuel cells

Brazilian filamentous fungi Rhizopus sp. (SIS-31), Aspergillus sp. (SIS-18) and Penicillium sp. (SIS-21), sources of oxidases were isolated from Caatinga's soils and applied during the in situ cathodic oxygen reduction in fuel cells. All strains were cultivated in submerged cultures using an optimized saline medium enriched with 10 g L⁻¹ of glucose, 3.0 g L⁻¹ of peptone and 0.0005 g L⁻¹ of CuSO₄ as enzyme inducer. Parameters of oxidase activity, glucose consumption and microbial growth were evaluated. In-cell experiments evaluated by chronoamperometry were performed and two different electrode compositions were also compared. Maximum current densities of 125.7, 98.7 and 11.5 μA cm⁻² were observed before 24 h and coulombic efficiencies of 56.5, 46.5 and 23.8% were obtained for SIS-31, SIS-21 and SIS-18, respectively. Conversely, maximum power outputs of 328.73, 288.80 and 197.77 mW m⁻³ were observed for SIS-18, SIS-21 and SIS-31, respectively. This work provides the primary experimental evidences that fungi isolated from the Caatinga region in Brazil can serve as efficient biocatalysts during the oxygen reduction in air-cathodes to improve electricity generation in MFCs.     

Biological hydrogen production from CO: Bioreactor performance

This paper presents an alternative solution to the current problem faced by the world; diminishing of fossil fuel. Bioconversion of synthesis gas to hydrogen as clean fuel was catalyzed by a photosynthetic bacterium, Rhodospirillum rubrum. The clean fuel production was biologically mediated by the water–gas shift reaction in a 2 l bioreactor. The work performed was on agitation effects on hydrogen production, K_La and power consumption. The results show that 500 rpm was the suitable agitation rate to be employed. The hydrogen production was optimized at 0.44 ± 0.023 atm giving a K_La of 86.4 ± 3.5 h⁻¹. The production rate was 9.6 mmol H₂/h. The maximum light conversion efficiency at agitation speed of 800 rpm, light intensity of 500 lux (732 kW/m²) and 4 g/l inlet acetate concentration was about 10.84 ± 1.73%. At this condition, the maximum CO conversion efficiency was found to be 81 ± 5.6%. The ratio of power per volume was calculated to be 322.30 ± 12.14 kW/m³ and foaming problem was successfully avoided. The corresponding power consumption was estimated to be about 0.64 ± 0.03 kW, while the output hydrogen energy was determined to be 643.2 ± 26 kW. A prolonged operation of continuous hydrogen production employing a microsparger showed stable behaviour for a duration of 27 days.     

Electricity from landfill leachate using microbial fuel cells: Comparison with a biological aerated filter

Four experimental columns were employed in this study to investigate their performance under wastewater treatment conditions. One column was set-up as a biological aerated filter and the remaining three were set-up as microbial fuel cells (MFCs), two of which were connected to an external load whereas the third was left open circuit. The performance of the columns under several flow rates and leachate strengths was studied in terms of BOD₅ removal efficiencies and electricity generation, when a fixed resistive load was connected. Results obtained demonstrated that it is possible to generate electricity and simultaneously treat landfill leachate in MFC columns. Energy generation in MFC columns improved with increasing flow rates from 24 to 192 mL/h, while BOD₅ removal efficiency levels reached a maximum at 48 mL/h and dropped to relatively low values at higher flow rates. The maximum removal efficiencies were obtained at a loading rate of 0.81 kg BOD₅/m³ d for columns C1, C2 and C4 and 1.81 kg BOD₅/m³ d for column C3. Electrical output levels and BOD₅ concentrations at the MFC columns showed a linear relationship, which allows the system to be used as a BOD₅ sensor. Part of the BOD removal was not associated with power generation and was attributed to the presence of alternative end terminal electron acceptors and volatilisation. The MFC columns could reach the same or even higher removal efficiencies than those from the biological aerated filter with the advantage of producing energy and saving cost of aeration. To the best of the authors’ knowledge, this is the first study that compares the MFC technology with other conventional treatment systems for removing pollutants from wastewater.     

Bioelectricity production from acidic food waste leachate using microbial fuel cells: Effect of microbial inocula

The effects of three different inocula (domestic wastewater, activated sludge, and anaerobic sludge) on the treatment of acidic food waste leachate in microbial fuel cells (MFCs) were evaluated. A food waste leachate (pH 4.76; 1000 mg chemical oxygen demand (COD)/L) was used as the substrate. The results indicate that the leachate itself can enable electricity production in an MFC, but the co-addition of different inocula significantly reduces the start-up time (approximately 7 days). High COD and volatile fatty acids removal (>87%) were obtained in all MFCs but with only low coulombic efficiencies (CEs) (14–20%). The highest power (432 mW/m³) and CE (20%) were obtained with anaerobic sludge as the co-inoculum. Microbial community analysis (PCR-DGGE) of the established biofilms suggested that the superior performance of the anaerobic sludge-MFC was associated with the enrichment of both fermentative (Clostridium sp. and Bacteroides sp.) and electrogenic bacteria (Magnetospirillum sp. and Geobacter sp.) at the anode.     

Capacities of soil water reservoirs and their better regression models by combining “merged groups PCA” in Chongqing,China

Soil water resource, together with the surface and sub-surface water resource, is essential to the regional water balance and world water cycle. A total of 90 soil samples were collected from 30 different soil profiles of dry fields throughout Chongqing, China randomly to show how soil could be a crucial part of water resources by discussing their five types of calculated soil water reservoir capacities, namely the total soil water reservoir capacity (mm) (TC), soil water storage capacity (mm) (SC), unavailable soil water reservoir capacity (mm) (UC), available soil water reservoir capacity (mm) (AC), and soil dead water storage capacity (mm) (DC) in certain layer, respectively. Overall, the total soil water reservoir capacity in 0–40 cm was about 209 mm, of which 70 mm belonged to available soil water reservoir capacity. Not all the five types of soil water reservoir capacities had significant correlations between each other. Soil structure, especially the size and quantity of soil pore was mainly determined by soil particle composition (clay, silt, and sand content). The more sand and less clay led to the more soil macropores, which provided room for soil water. Thus, clay, silt, and sand content jointly produced profound influence on soil water reservoir capacities. Nevertheless, specific water capacity and topographic factors displayed weak correlations to soil water reservoir capacities, which required further research works. Ultimately, the better regression models were achieved by multiple regression analysis coupled with “merged groups PCA” than by multiple regression analysis with “all variables PCA”. UC, SC, TC and DC could be well simulated (mostly R² > 0.70; P < 0.05) through normal multiple regression analysis using original variables as well as multiple regression analysis with “merged groups PCA”. Only regression models of TC and DC were highly significant (mostly R² > 0.70; P < 0.05) through “all variables PCA” method. And there were poor coefficients of determination (R²) for AC (mostly R² < 0.40; P < 0.05) by all the three regression methods.     

The effects of accelerometer placement on mechanomyographic amplitude and mean power frequency during cycle ergometry

The purposes of this study were threefold: (1) to compare the power output related patterns of absolute and normalized MMG amplitude and MPF responses for proximal and distal accelerometer placements on the vastus lateralis (VL) muscle during incremental cycle ergometry; (2) to examine the influence of accelerometer placements on mean absolute MMG amplitude and MPF values; and (3) to determine the effects of normalization on mean MMG amplitude and MPF values from proximal and distal accelerometer placements. Fifteen adults (10 men and 5 women; mean ± SD age = 23.9 ± 3.1 years) performed incremental cycle ergometry tests to exhaustion. Two accelerometers were placed proximal and distal on the VL muscle. Paired t-tests indicated that absolute MMG amplitude values for the proximal accelerometer were greater (p < 0.05) than the distal accelerometer at all power outputs. The normalized MMG amplitude also had greater values for the proximal accelerometer at all power outputs, except 50 W. There were no differences, however, between proximal and distal accelerometers for absolute MMG MPF, except at 75 W, and normalization eliminated this difference. Twenty-seven percent of the subjects exhibited different power output related patterns of responses between accelerometer placements for MMG amplitude and 47% exhibited different patterns for MPF. These findings indicated that normalization did not eliminate the influence of accelerometer placement on MMG amplitude and highlighted the importance of standardizing accelerometer placements to compare MMG values during cycle ergometry.     

Integrating insecticides and Trichogramma ostriniae to control European corn borer in sweet corn: Economic analysis

We compared the economics of controlling European corn borer (Ostrinia nubilalis) in sweet corn by using the egg parasitoid, Trichogramma ostriniae, alone and integrated with insecticidal sprays. An initial experiment in 2003 compared T. ostriniae alone against insecticide alone and a second set of experiments conducted over 3 years (2006–2008) compared (1) insecticide alone [Insecticide]; (2) no insecticide, no T. ostriniae [Untreated Check]; (3) T. ostriniae alone [T. ostriniae 1X]; and (4) T. ostriniae + insecticide [Integrated]. In 2007 and 2008, a fifth treatment was added consisting of three approximately weekly releases of T. ostriniae [T. ostriniae 3X]. Parasitism of O. nubilalis eggs was higher in plots receiving T. ostriniae; O. nubilalis eclosion was lower with T. ostriniae; there was no interaction of T. ostriniae and insecticide on parasitism, O. nubilalis eclosion, or total O. nubilalis larvae at harvest time. Partial crop budgets were conducted for each treatment. In three of the 4 years, Untreated Checks had the highest sweet corn ear damage. Ear damage after a single release of T. ostriniae was statistically no different than using insecticides. In two of the three years, the Integrated treatment (T. ostriniae 1X + insecticide) generated the largest increase in profitability. The insecticide only treatment generated the second best increase in profitability. When comparing a single release of T. ostriniae to the insecticide only, the latter provided a better combination of efficacy and profitability. The breakeven costs of the T. ostriniae justified their use relative to the Untreated Check treatment, but not when compared to the Insecticide treatment. The breakeven costs for T. ostriniae in the Integrated treatment exceeded the actual cost in two out of three years, suggesting again that conventional growers could benefit from integrating T. ostriniae with insecticidal treatments. Projected profitability based on ear packout obtained by combining data among years suggests that in general, for low prices and yields, the increase in profit is quite modest. In the lowest price-yield combination, the change in profit is T. ostriniae 3X > Integrated > Insecticide > T. ostriniae 1X ? Untreated Check. At high prices and high yields, the differences between the management options when compared to Untreated Check are considerable. In the highest price-yield combination, the change in profit is T. ostriniae 3X > Integrated ? Insecticide > T. ostriniae 1X ? Untreated Check.     

Mixing at the beginning of fattening moderates social buffering in beef bulls

Cattle establish strong preferential associations early in their life that determine the cohesiveness within a group and can diminish fear responses (i.e. social buffering). Mixing beef bulls at the beginning of fattening may lead to less cohesiveness. Moreover, mixing beef bulls induces aggressive interactions, especially when the bulls are of similar weights. This study was aimed at evaluating the cohesiveness and fear responses of 64 bulls that were either mixed versus unmixed and of homogeneous vs. heterogeneous body weights (2 × 2 factorial design, four groups of four bulls each per treatment). Social cohesiveness was assessed during food competition and a social separation test. Fear responses were observed during the social separation test and pre-slaughter handling. During food competition, unmixed bulls exchanged more non-agonistic interactions (P < 0.05) and were more tolerant with each other than mixed bulls (time spent eating: P < 0.05). Unmixed bulls displayed less fear responses during physical separation (elimination: P < 0.05; startle: P < 0.01) and were less stressed by pre-slaughter handling (blood cortisol: P < 0.05). Very few effects could be attributed to the homogeneity of weights within groups. It is concluded that mixing bulls at the beginning of fattening reduces the strength of positive social relationships and renders social buffering less effective during subsequent fattening. We recommend maintaining familiar bulls together throughout fattening in order to preserve cohesiveness within groups and for animals to benefit from social buffering during stressful situations.     

Scale-up of micro-aerobic 1,3-propanediol production with Klebsiella pneumonia CGMCC 1.6366

The conversion of glycerol to 1,3-propanediol (1,3-PD) using Klebsiella pneumoniae CGMCC 1.6366 under aerobic condition was scaled up from scale 5 to 50,000 l in series. Several parameters including power input P/V_l, agitation rate n, impeller tip speed nD, superficial gas velocity u_s, and Re_s were investigated as the criteria for scaling up. Impeller tip speed was chosen as the main criterion. It was also noticed less aeration was favored in that less electron will be shunted to electron transfer chain. The fermentation in 500 l bioreactor produced 66.8 g 1,3-PD with the yield of 0.55 mol mol^?1 at agitation rate and aeration of 130 rpm and 0.14 vvm air flow. Using these empirically obtained control concepts we successfully scaled up in 500–50,000 l pilot-scale reactors. The final 1,3-PD concentrations in 50,000 l bioreactor amounted to 63.3 g l^?1 with the yield of 0.5 mol mol^?1.