جستجوی مقالات مرتبط با کلیدواژه "biohydrogen" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

Biohydrogen production by microorganisms including Clostridium and Enterobacter are covered. Artificial microbial consortia have no complications as the pure culture. Further avails the effect of environments interaction on each other and yield of hydrogen production. The present review paper discloses the pathway of hydrogen production by Enterobacter and Clostridium, the rate of growth of the microorganism, The potential of carbohydrate substrate metabolism, pH and temperature influence, and the ratio of experimental to theoretical yield under anaerobic conditions. Enterobacter by Pyruvate formate-lyase (PFL) and Clostridium Pyruvate-ferredoxin oxidoreductase (PFOR) yield 2 mol / mol glucose and 4 mol / mol glucose. On the count of the present comparison 1.36 to 2.205 mol /mol glucose produced by Enterobacter and Clostridium, respectively, 38% discrepancy of practical yield is observed. For hydrogen production Clostridium needs strict anaerobic environments and L-cysteine are added, while Enterobacter in consortia uses oxygen and as a result the production cost is reduced. The consortia are potential to metabolize simple and complex carbon sources like glucose, starch wastewater and lignocellulose wastes. Moreover, reasonably high inoculate ratio of Enterobacter, pH, and, temperature ranges of 5-7 and 30-39°C are effective for biohydrogen production.
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Biofuels are a new priority to reduce fossil fuel consumption, its contamination and the problem of waste disposal, hence extensive research has been done on biofuels production, effective factors, and optimization of the process. Production of biodiesel and bioethanol from organic waste is possible on an industrial scale. Volatile fatty acids can be produced from organic waste and then turn to biogas, biohydrogen, and biodiesel. In this paper, the production of biodiesel fuel, biohydrogen, volatile fatty acids and its conversion to biodiesel are discussed. Biodiesel production by transesterification in the presence of a catalyst is an appropriate method. Moreover, dark fermentation produces the most amount of biohydrogen and it needs the lowest volume reactor among other biological methods. In this paper, firstly different methods of biodiesel production and effective parameters and then, biohydrogen production and effective parameters have been discussed

Dark fermentative hydrogen production is an elaborated multiproduct process that takes place in the absence of light and oxygen. In present paper effect of chemical and physical mutagens on increasing dark fermentative hydrogen production using Enterobacter strain is reviewed. The hydrogen production rate of mutant compared to the wild strain was increased and other metabolite production was decreased by using both chemical and physical mutagens. The various techniques such as testing sugar utilization efficiency, suicide substrate, suicide protons and Voges–Proskauer was used for screening mutant cells. However, the hydrogen production rate as index for selection the best mutant has been considered. Hydrogen production by using chemical mutagens was higher than physical mutagens.

Dark fermentative biohydrogen production is a complex multiproduct process and is affected by many parameters. In the present review, effect of a wide range of parameters such as inoculum, temperature, pH, hydraulic retention time, bioreactor configuration, hydrogen partial pressure, substrate type and concentration, nutrient type and concentration in dark fermentative biohydrogen production is addressed. Most of the studies on dark fermentative biohydrogen production have been conducted in batch mode using glucose and sucrose as substrate, thus future studies in continuous mode using organic wastes and inexpensive substrates are desirable.