scholarly journals Enhancing Hydrogen Productivity of Photosynthetic Bacteria from the Formulated Carbon Components of Lignocellulose

2021 ◽  
Author(s):  
Chuan Zhang ◽  
Guihong Wang ◽  
Shuaishuai Ma ◽  
Hao Huang ◽  
Yixiao Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Photosynthetic Bacteria ◽  
Biohydrogen Production ◽  
Total Carbon ◽  
Carbon Substrate ◽  
Hydrogen Production Rate ◽  
Glucose Content ◽  
Initial Concentration ◽  
Maximum Value ◽  
Initial Carbon

Abstract To develop an efficient photofermentative process capable of higher rate biohydrogen production using carbon components of lignocellulosic hydrolysate, a desired carbon substrate by mixing xylose with glucose was formulated. Effects of crucial process parameters affecting cellular biochemical reaction of hydrogen by photosynthetic bacteria (PSB), i.e variation in initial concentration of total carbon, glucose content in initial carbon substrate, as well as light intensity were experimental investigated using response surface methodology (RSM) with a Box-Benhnken design (BBD). Hydrogen production rate (HPR) in the maximum value of 30.6 mL h− 1 L− 1 was attained under conditions of 39 mM initial concentration of total carbon, 59% (mol/mol) glucose content in initial carbon substrate and 12.6 W m− 2 light intensity at light wavelength of 590 nm. Synergic effects of metabolizing such a well formulated carbon substrate for sustaining the active microbial synthesis to sufficiently accumulate biomass in bioreactor, as well as stimulating enzyme activity of nitrogenase for the higher rate biohydrogen production were attributed to this carbon substrate can enable PSB to maintain the relatively consistent microenvironment in suitable culture pH condition during the optimized photofermentative process.

Transfer of photosynthetically fixed carbon between the prokaryotic green alga Prochloron and its ascidian host

1983 ◽  
Vol 34 (3) ◽  
pp. 431 ◽  
Author(s):  
DJ Griffiths ◽  
L Thinh
Keyword(s):  
Light Intensity ◽  
Green Alga ◽  
Host Tissue ◽  
Total Carbon ◽  
Symbiotic Association ◽  
Fixed Carbon ◽  
Low Light ◽  
Ascidian Species ◽  
Dark Fixation ◽  
Efficient Transfer

In the symbiotic association between the prokaryotic green alga Prochloron and three didemnid host species (Diplosoma similis, Lissoclinum bistratum, Trididemnum cyclops), between 6 and 51 % of the total carbon fixed during exposure for 1 h to H14CO3- in the light (150 �E m-2 s-1) becomes associated with the host tissue. Dark fixation of 14CO2 in these ascidian species and in Lissoclinum punctatum never exceeds 6% of photosynthetic fixation at saturating light intensity. The corresponding values for dark fixation of 14CO2 in isolated Prochloron cells fall within the same range. There is very little excretion of photosynthate from whole colonies of the above ascidian species nor from Didemnum molle, Lissoclinum voeltzkowi and Trididemnum miniatum (usually less than 1 % of total photosynthate at saturation light intensity), suggesting an efficient transfer mechanism from Prochloron to host. Evidence from pulse-chase experiments suggests that transfer probably involves the early products of photosynthesis. The extent of transfer of photosynthate between Prochloron and T. cyclops varies with the rate of photosynthetic 14CO2 fixation into the whole colony but there is some transfer even at low light intensities, which strongly limit photosynthesis.

scholarly journals Frontal Polymerization in Acrylic Acid System

2011 ◽  
Vol 8 (1) ◽  
pp. 75-82
Author(s):  
P. K. Srivastava ◽  
S. S. Majhi ◽  
B. K. Sarkar
Keyword(s):  
Acrylic Acid ◽  
Benzoyl Peroxide ◽  
Reaction Temperature ◽  
Test Tube ◽  
Frontal Polymerization ◽  
Initial Reaction ◽  
Initial Concentration ◽  
Maximum Value ◽  
Front Position ◽  
Initial Starting

Moving wave front have been investigated in acrylic acid / benzoyl peroxide / N, N-dimethyl aniline system in a test tube at 30oC temperature. Dependence of front velocity on initial concentration of benzoyl peroxide, and effect of hydroquinone was determined. Consumption of acrylic acid and benzoyl peroxide have been found to decrease exponentially with respect to front position. The variation of reaction temperature with respect to front position at different initial concentration of benzoyl peroxide and different initial starting temperature have been investigated. It has been established that the reaction temperature increases and attains a maximum value by increasing both benzoyl peroxide and initial reaction temperature. The rate of polyacrylic acid chain propagation has been determined.

Use of Experimental Designs to Establish a Kinetic Law for a Gas Phase Photocatalytic Process

2014 ◽  
Vol 12 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Cécile Raillard ◽  
Audrey Maudhuit ◽  
Valérie Héquet ◽  
Laurence Le Coq ◽  
Jean Sablayrolles ◽  
...  
Keyword(s):  
Light Intensity ◽  
Photocatalytic Degradation ◽  
Gas Phase ◽  
Photocatalytic Oxidation ◽  
Experimental Designs ◽  
Photocatalytic Process ◽  
Air Velocity ◽  
Kinetic Rate ◽  
Initial Concentration ◽  
Designs Of Experiments

Abstract The photocatalytic degradation of three common indoor VOCs – acetone, toluene and heptane – is investigated in a dynamic photocatalytic oxidation loop using Box–Behnken designs of experiments. Thanks to the experimental results and the establishment of a kinetic rate law based on a simplified mechanism, a predictive model for the VOC degradation involving independent factors is developed. The parameters under investigation are initial concentration, light intensity and air velocity through the photocatalytic medium. The obtained model fits properly the experimental curves in the range of concentration, light intensity and air flow studied.

Preliminary Study of Photosynthetic Bacteria Treating Hydrothermal Liquefaction Wastewater

2014 ◽  
Vol 1073-1076 ◽  
pp. 810-816
Author(s):  
Guo Yang Yuan ◽  
Hai Feng Lu ◽  
Shi Wei Huang ◽  
Yuan Hui Zhang ◽  
Bao Ming Li ◽  
...  
Keyword(s):  
Light Intensity ◽  
Environmental Pollution ◽  
Biomass Production ◽  
Photosynthetic Bacteria ◽  
Resource Recovery ◽  
Inoculum Size ◽  
Hydrothermal Liquefaction ◽  
Treatment Conditions ◽  
Preliminary Study ◽  
Biocrude Oil

Post hydrothermal liquefaction wastewater (PHWW) was generated during biocrude oil production. It contains lots of carbon, nitrogen and phosphorous elements, which can cause environmental pollution and resource waste. Using photosynthetic bacteria (PSB) to treat this kind of wastewater can realize pollutants elimination and resource recovery. In this work, the feasibility of using PSB to treat PHWW was firstly investigated, and the treatment conditions were optimized. Results showed that the PSB can effectively degrade PHWW. The optimal initial COD concentration, inoculum size and light intensity for PSB to treat PHWW were 6000-10000 mg/L, 50 mg/L and 1000-3500 lux, respectively. With the initial COD concentration of 9000 mg/L, inoculum size of 50 mg/L and light intensity of 1000 lux, the COD, NH3-N, TP removal and biomass production reached to 71%, 90%, 47.2% and 773 mg/L, respectively. This showed that using PSB to treat PHWW can be an alternative method for PHWW nutrients recovery and pollutant treatment.

One-carbon substrate-based biohydrogen production: Microbes, mechanism, and productivity

2015 ◽  
Vol 33 (1) ◽  
pp. 165-177 ◽  
Author(s):  
Simon K.-M.R. Rittmann ◽  
Hyun Sook Lee ◽  
Jae Kyu Lim ◽  
Tae Wan Kim ◽  
Jung-Hyun Lee ◽  
...  
Keyword(s):  
Biohydrogen Production ◽  
Carbon Substrate

scholarly journals Modelling of quantum yields in photocatalytic membrane reactors immobilising titanium dioxide

2006 ◽  
Vol 2006 ◽  
pp. 1-8 ◽  
Author(s):  
Ignazio Renato Bellobono ◽  
Giulia de Martini ◽  
Paola Maria Tozzi ◽  
Carmen Canevali ◽  
Franca Morazzoni ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Membrane Reactors ◽  
Quantum Yields ◽  
Peroxide Formation ◽  
Initial Concentration ◽  
A Value ◽  
Maximum Value ◽  
Radiant Power ◽  
Hydrogen Peroxide Formation ◽  
Kinetics Of

For some model molecules (methanoic and ethanoic acids, methane, and phenol), systematic investigations of quantum yields were carried out in the present paper, as a function of concentration and of absorbed radiant power. Quantum yieldsΦ∞, calculated from rates, followed an apparently Langmuirian function of initial concentrationC0, by whichΦ∞values at “infinite” concentration could be obtained. By having thus established that quantum yields of photomineralisationΦ∞are independent of radiation wavelength, within the absorption range of semiconductor, but depend on radiant power, such a dependency was experimentally investigated. For all the investigated molecules, the maximum allowable values reached in the low radiant power range clearly appeared as a plateau. On the contrary, at high radiant power values, another plateau, at a value of about 1/4-1/5 with respect to the maximum value, was evident. This was interpreted on the basis of a competition kinetics of hydroxyl radicals with themselves, leading to hydrogen peroxide formation, other than with substrate or intermediate molecules leading to full mineralisation. Modelling of quantum yields as a function of concentration and radiant power thus allows a fully consistent and trustworthy design of photoreactors.

Purification of Methylene Blue via Photocatalytic Nanofibrous Membranes Containing TiO2 Nanoparticles

2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100
Author(s):  
Ali Sajjadi ◽  
Seyed Abdolkarim Hosseini Ravandi ◽  
Hossein Izadan ◽  
Nastaran Kadivar
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Cross Flow ◽  
Filtration Efficiency ◽  
Blue Dye ◽  
Carbon Substrate ◽  
Initial Concentration ◽  
The Cross ◽  
Uv Rays

In this paper, titanium dioxide nanoparticles were synthesized on polyacrylonitrile nanofiber membranes via a sol-gel process. Filter structure consisted of a non-woven polyurethane-carbon substrate, polyacrylonitrile nanofiber and titanium dioxide nanoparticles. The concentration of methylene blue dye solution was measured via UV radiation. The filtration efficiency was calculated via Langmuir-Hinshelwood pseudo-first order equations. The results showed that the filtration efficiency of samples using titanium dioxide under UV rays was higher than those without titanium dioxide and UV rays in both immersing and cross-flow processes. Degradation efficiency of the cross-flow system was three times higher than that of immersing method. In the cross-flow process, the effect of three variables-pressure on the membrane, initial concentration of dye solution and pH of the dye solution was studied under UV rays. The highest efficiency obtained was 90.3% by using 1.5 bar pressure, 40 μM initial concentration and pH of 4.1.

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