Biomass production and studies on Rhodopseudomonas palustris grown in an outdoor, temperature controlled, underwater tubular photobioreactor

The main goal of this study was to increase the hydrogen production rate improving the culture technique and the photobioreactor performances. Experiments were carried out at a constant culture temperature of 30°C and at an average irradiance of 480 W m−2using a cylindrical photobioreactor (4.0 cm, internal diameter). The culture technique, namely, the semicontinuous regime for growingRhodopseudomonas palustris42OL made it possible to achieve a very high daily hydrogen production rate of 594 ± 61 mL (H2) L−1 d−1. This value, never reported for this strain, corresponds to about 25 mL (H2) L−1 h−1, and it was obtained when the hydraulic retention time (HRT) was of 225 hours. Under the same growth conditions, a very high biomass production rate (496 ± 45 mg (dw) L−1 d−1) was also achieved. Higher or lower HRTs caused a reduction in both the hydrogen and the biomass production rates. The malic-acid removal efficiency (MAre) was always higher than 90%. The maximal hydrogen yield was 3.03 mol H2mol MA−1at the HRT of 360 hours. The highest total energy conversion efficiency was achieved at the HRT of 225 hours.

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Investigating and modelling the effect of light intensity on Rhodopseudomonas palustris growth

10.22541/au.162957684.44530483/v1 ◽

2021 ◽

Author(s):

Brandon Ross ◽

Robert William McClelland Pott

Keyword(s):

Experimental Data ◽

Light Intensity ◽

Photosynthetic Bacteria ◽

Rhodopseudomonas Palustris ◽

Photosynthetic Bacterium ◽

Light Penetration ◽

Tubular Photobioreactor ◽

Photobioreactor Design ◽

High Purity Hydrogen ◽

Effect Of Light

Photosynthetic bacteria can be useful biotechnological tools – they produce a variety of valuable products, including high purity hydrogen, and can simultaneously treat recalcitrant wastewaters. However, while photobioreactors have been designed and modelled for photosynthetic algae and cyanobacteria, there has been less work on understanding the effect of light in photosynthetic bacterial fermentations. In order to design photobioreactors, and processes using these organisms, robust models of light penetration, utilisation and conversion are needed. This article uses experimental data from a tubular photobioreactor designed to focus in on light intensity effects, to model the effect of light intensity on the growth of Rhodopseudomonas palustris, a model photosynthetic bacterium. The work demonstrates that growth is controlled by light intensity, and that this organism does experience photoinhibition above 600 W/m2, which has implications for outdoor applications. Further, the work presents a model for light penetration in circular photobioreactors, which tends to be the most common geometry. The work extends the modelling tools for these organisms, and will allow for better photobioreactor design, and the integration of modelling tools in designing processes which use photosynthetic bacteria.

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Sustained outdoor H2 production with Rhodopseudomonas palustris cultures in a 50L tubular photobioreactor

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2012.01.081 ◽

2012 ◽

Vol 37 (10) ◽

pp. 8840-8849 ◽

Cited By ~ 43

Author(s):

Alessandra Adessi ◽

Giuseppe Torzillo ◽

Enrico Baccetti ◽

Roberto De Philippis

Keyword(s):

Rhodopseudomonas Palustris ◽

H2 Production ◽

Tubular Photobioreactor

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Construction and Performance of a Self-Contained, Temperature-Controlled Heat Source (Electronic Chicken) to Quantify Thermal Load during Live Haul of Broilers

Applied Engineering in Agriculture ◽

10.13031/aea.12654 ◽

2018 ◽

Vol 34 (5) ◽

pp. 865-874 ◽

Cited By ~ 1

Author(s):

Kaushik Luthra ◽

Yi Liang ◽

James R Andress ◽

Thomas A Costello ◽

Susan E Watkins ◽

...

Keyword(s):

Heat Source ◽

Heat Loss ◽

Heat Production ◽

Management Practices ◽

Physiological Stress ◽

Sensible Heat ◽

Outdoor Temperature ◽

Positive Correlation ◽

Temperature Range ◽

Temperature Controlled

Abstract. Strategies for quantifying heat loss of broilers on live-haul trailers would be beneficial, particularly under conditions of environmental extremes. We have developed an electronic chicken (a self-contained, temperature-controlled heat source) to simulate the sensible heat loss of a live broiler during the transit and holding periods in commercial live-haul trips. The simulated electronic chicken is an aluminum box, having surface area equivalent to a 2.3 to 2.8 kg broiler chicken (0.13 m2), with a thermostatically controlled power source to maintain the internal temperature at 41°C (typical broiler core body temperature). Different cover materials were tested to identify an appropriate cover that resulted in measured values of electronic chicken heat production being similar to published values of sensible heat production for broilers. A double layer of fleece fabric provided a reasonable match. The sensible heat loss of the electronic chickens exhibited positive correlation with exposed wind, and a positive correlation with temperature gradient between internal and external environment. Wetting the fabric cover of electronic chickens only slightly increased heat loss as compared to the dry fabric cover. Wet fabric cover experienced lower heat loss than that expected from the wetted surface of a live chicken, therefore heat loss under the wet scenario would be underestimated. Electronic chickens were installed in modules on trailers with live chickens during commercial live-haul process under various environmental conditions and different management practices. Measured heat losses from electronic chickens were in the range of 8.2 to 20.3 W with outside temperature of -17°C to 3.0°C in winter, and 4.5 to 6.7 W with 28°C to 34°C in summer. Based on literature-reported sensible heat loss under thermoneutrality, it was determined that the measured air temperature inside the live-haul modules on the trailer in the range of 11°C to 25.1°C during transit (outdoor temperature range of 1.7°C to 22.2°C) and 5.3°C to 21.7°C during holding (outdoor temperature range of -9.1°C to 19.8°C) would allow the live chickens to regulate heat by their metabolism and stay comfortable. For the holding period, the winter trips were mostly in the zone of thermal comfort. In summers, hyperthermic conditions were possible during transit, although additional cooling due to surface wetting of birds as a result of misting (on the farm prior to beginning the transit) could have been beneficial but not detectable by electronic chickens. The electronic chickens can be used effectively as a model to evaluate and identify conditions that cause thermal stress conditions during live-haul conditions and to design systems and strategies to alleviate that stress. Keywords: Broiler transport, Physiological stress, Thermal micro-environment, Thermoneutral zone.

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