Enhanced hydrogen production by photofermentative microbial aggregation induced byl-cysteine: the effect of substrate concentration, C/N ratio and agitation rate

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91120-91126 ◽  
Author(s):  
Guo-Jun Xie ◽  
Bing-Feng Liu ◽  
Jie Ding ◽  
Defeng Xing ◽  
Qilin Wang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Substrate Concentration ◽  
Organic Waste ◽  
Agitation Rate ◽  
Retention Capacity ◽  
Biomass Retention ◽  
Electron Sink

Aggregation of photofermentative bacteria enhances the biomass retention capacity of photobioreactor, and maximizes the reductant flow from organic waste into hydrogen production through circumventing electron sink to biomass synthesis.

Continuous hydrogen production from organic waste

2005 ◽  
Vol 52 (1-2) ◽  
pp. 145-151 ◽  
Author(s):  
T. Noike ◽  
I.B. Ko ◽  
S. Yokoyama ◽  
Y. Kohno ◽  
Y.Y. Li
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Hydrogen Production ◽  
Metabolic Pathway ◽  
Substrate Concentration ◽  
Acid Production ◽  
Organic Waste ◽  
Batch Experiments ◽  
Production Experiment ◽  
Propionic Acid Production

The antibiotic effects of lactic acid bacteria, Lactobacillus paracasei, on hydrogen production were investigated using glucose as the substrate for the batch experiments. The effects of lactic acid bacteria on hydrogen fermentation depended on pH and the inhibition of hydrogen-producing bacteria was prevented by keeping the pH over 5.0. Then, a continuous hydrogen production experiment was conducted by using bean curd manufacturing waste as an actual organic waste at pH 5.5 at 35 °C. The increase of the substrate concentration and the addition of nitrogen gave precedence to acetic and butyric acids production in the metabolic pathway and suppressed propionic acid production. As the result, continuous hydrogen production from municipal organic waste was enabled.

Effect of Short-Term Temperature Increase on the Performance of a Mesophilic UASB Reactor

1990 ◽  
Vol 22 (9) ◽  
pp. 183-190 ◽  
Author(s):  
J. B. van Lier ◽  
J. Rintala ◽  
J. L. Sanz Martin ◽  
G. Lettinga
Keyword(s):  
Sharp Decrease ◽  
Methanogenic Bacteria ◽  
Decay Rates ◽  
Uasb Reactor ◽  
Short Term ◽  
Retention Capacity ◽  
Temperature Shock ◽  
Biomass Retention ◽  
Propionate Oxidation ◽  
Ph Decrease

A study was carried out to assess the effects of short-term temperature increments on the treatment efficiency and methane production of UASB reactors at a working temperature of 37-39°C. Two different substrates were used to determine the effects on the several bacterial groups involved in the digestion process. One reactor was fed with defined synthetic acidified wastewater the other with unacidified wastewaler from a distillery process. Shocks of 5-24 hrs were applied at temperatures in the range of 45 to 61°C. Up to 45°C no detrimental effects were noticeable. Higher temperatures led to a sharp decrease of the activity of the different microbial populations as a result of elevated decay rates. Propionate oxidation turned out to be the most sensitive for temperature increments, whereas the acidogenic bacteria were least affected. Temperature shocks of 55 and 61°C led to a decrease of 50% of the overall efficiency after 10 and 3 hrs, respectively. By means of batch experiments decay rates of 0.44 and > 10 hr −1 of the methanogenic bacteria were estimated at 55 and 65°C respectively. As temporary inactivation of the mesophilic bacteria during a temperature shock was found to be unlikely, reactor recovery is dependent on the bacterial growth and the biomass retention capacity of the reactor. When unacidified wastewater is treated, a pH decrease has to be considered during a temperature shock.

Hydrogen production from organic waste

2001 ◽  
Vol 26 (6) ◽  
pp. 547-550 ◽  
Author(s):  
Annika T Nielsen ◽  
Helena Amandusson ◽  
Robert Bjorklund ◽  
Helen Dannetun ◽  
Jörgen Ejlertsson ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Organic Waste

Photocatalytic and photoelectrochemical hydrogen production by photodegradation of organic substances

2009 ◽  
Vol 81 (8) ◽  
pp. 1441-1448 ◽  
Author(s):  
Panagiotis Lianos ◽  
Nikoleta Strataki ◽  
Maria Antoniadou
Keyword(s):  
Titanium Dioxide ◽  
Hydrogen Production ◽  
Organic Waste ◽  
Current Trend ◽  
Waste Materials ◽  
Organic Substances ◽  
Nanocrystalline Titania ◽  
Photoelectrochemical Hydrogen Production

Commercial nanocrystalline titania (titanium dioxide, TiO2) has been used to make TiO2 films, which were employed to photodegrade several organic substances under photocatalytic (PC) or photoelectrochemical (PEC) operation. Hydrogen was produced during both operations while electricity was additionally produced during the PEC operation. Both processes were studied as typical examples of the current trend in the effort to produce useful forms of energy by photodegradation of organic waste materials.

Application of modified ADM1 to long-term experiments for methane/hydrogen production from model organic waste

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Soda ◽  
K. Wada ◽  
M. Okuda ◽  
M. Ike
Keyword(s):  
Hydrogen Production ◽  
Methane Production ◽  
Organic Waste ◽  
Degradation Pathways ◽  
Bacterial Populations ◽  
Degrading Bacteria ◽  
Production Experiment ◽  
Methane Production Rate ◽  
Simulation Results

The modified ADM1 including lactate and ethanol was verified using experimental data for methane/hydrogen production processes from model organic waste. Monosaccharides were presumably degraded into acetate, lactate, butyrate, and ethanol; lactate is further degraded into propionate and acetate; ethanol is degraded into acetate. The methane production experiment was carried out using an 8-L reactor operated at 55°C, pH 6.8, and sludge retention time (SRT) of 7–20 days for 370 days. Concentrations of carbohydrates, monosaccharides, butyrate, propionate, valerate, acetate, and the methane production rate were simulated well by the modified ADM1. The ratio of degradation pathways from monosaccharides to acetate, lactate, butyrate, and ethanol were inferred, respectively, to be 0.4, 0.6, 0.0, and 0.0. The hydrogen production experiment was carried out using a 2-L (1.5L) reactor operated at 35°C, pH 6.0-6.5, and SRT of 0.5–2.0 days for 370 days. The simulation results suggested that all bacterial populations except the sugar-degrading bacteria were washed out from the reactor because of the short SRT. The respective ratios of degradation pathways from monosaccharides to acetate, lactate, propionate, and ethanol were inferred to be 0.55, 0.0, 0.4, and 0.05 at pH 6.5 and 0.7, 0.2, 0.05 and 0.05 at pH 6.0.

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