the stoichiometric parameter namely “yield coefficient” associated with growth of certain organism can be determined by direct measurement and/or calculated indirectly. the focus of this paper was on the anoxic yield of heterotrophic organisms using ethanol as an external carbon source during the denitrification process. in the literature, it was observed that yield coefficients can vary for th...

Soil carbon and nitrogen contents play an important role in sustaining soil physical and chemical quality and help to have healthy environments. The continues conversion of rangelands to arable lands has the potential to change carbon and nitrogen sequestration. In this study to evaluate the effects of land use change on soil organic carbon and nitrogen stock, forty samples collected from north...

in order to investigate the effects of soil chemical characteristics on weed species diversity in eastern mashhad region wheat (triticum aestivum l.) fields, an investigation was held in the year 2009. wheat fields were classified based on the acreage from 3-5, 5-10 and higher than 10 ha. five random soil samples were taken using a 5 cm diameter auger from the soil of each experimental field an...

In this study, favorable carbon-nitrogen ratio for high yields of gibberellic acid (GA3) production from Pseudomonas sp. was investigated. First of all, optimum carbon (glucose, maltose, sucrose, fructose, lactose) and nitrogen (KNO3, NH4Cl, NaNO3, urea, glycine) sources among the others were chosen. The highest yield of GA3 productivity was found in growth medium supplemented with fructose (16...

polyhydroxyalkanoates (phas) are bioplastics derived from renewable resources such as vegetable oils, corn starch, or microbes. the polyhydroxybutyrate (phb) is a short-chain-length pha, and the most important bioplastic produced by certain microorganisms in the presence of excess carbon sources. in this study batch cultivation of alcaligenes eutrophus with the aim of increasing phb production ...

Pseudomonas putida CA-3 is capable of converting the aromatic hydrocarbon styrene, its metabolite phenylacetic acid, and glucose into polyhydroxyalkanoate (PHA) when a limiting concentration of nitrogen (as sodium ammonium phosphate) is supplied to the growth medium. PHA accumulation occurs to a low level when the nitrogen concentration drops below 26.8 mg/liter and increases rapidly once the n...

The aim of this research was to compare the amounts of existing mineral elements in plant aerial parts, litter and soil ofthree range species (Bromus tomentellus, Psathyrostachys fragilis, Agropyron tauri) in order to investigate the litter effectof species on soil properties of Taleghan rangeland. The measured mineral elements include carbon, nitrogen,phosphorous and potassium. After selection...