Kjeldahl factors

By means of the Kjeldahl factors F (Table 1.7) the amount of protein is... 

Protein content was determined by a semi-automated micro-Kjeldahl method [4], The conversion factor used was 6.25. 

The quantity of protein present is normally measured by the Kjeldahl method. As wheat endosperm protein is around 17.5% nitrogen a factor of 5.7 is normally used to convert Kjeldahl nitrogen measurements into protein. Tkachuk suggested that 5.7 should be used for whole wheat but 5.6 should be used for flour.24... 

The amount of protein in the substrate solution can be determined by using the Kjeldahl method (unit Bl.2) to determine the nitrogen concentration (N) and then multiplying this by a factor of 6.25 (fN). 

Multiplying the total nitrogen content by the Kjeldahl conversion factor of 6.38 yields the protein content. 

Protein content in the feedstock was estimated by the Kjeldahl method (26) using the N x 6.25 conversion factor. Moisture content of the samples was determined by oven drying at 105°C to constant weight. 

To estimate crude protein content of biomass or other materials, the nitrogen content of the material is measured by Kjeldahl or combustion methods and multiplied by a conversion factor where ... 

The term biomass will be neglected in later reactions, since all biochemical reactions require and produce biomass. Temperature, pH, dissolved oxygen, and the ratio of BOD to total Kjeldahl nitrogen (TKN) are important factors in nitrification. 

Quantitative acid hydrolysis with 72% (w/w) H2SO4 [19] was used to characterize the BSG feedstock. The monosaccharides and acetic acid were determined by HPLC to estimate (after corrections for stoichiometry and sugar decomposition) the contents of glucan (cellulose) and hemicelluloses (xylan, arabinan, and acetyl groups) in the sample. The acid-insoluble residue after hydrolysis was recovered by filtration and considered as Klason lignin after correction for the acid-insoluble ash. Protein was determined by the KJeldahl method [20] using the Ax 6.25 conversion factor. 

Protein content in the yeast biomass was also determined by the Kjeldahl method using the conversion factor of 6.25. Total carbohydrates in yeast biomass were determined by the anthrone method [21]. RNA content was determined by the Schmidt-Thannhauser method as described in Benthin et al. [22]. Fat content was determined in dried cells by a Soxhlet extraction procedure using petroleum ether (60-80 °C) as solvent [23]. Ash content was determined by igniting the samples at 575 °C for 5 h, both for the feedstock and yeast biomass. All results are reported on the dry basis. 

Table 17.2 indicates that sufficient nutrients in the form of a carbon source (DOC), nitrogen (N-Kjeldahl), and phosphorus are present in the groundwater.The concentration of nitrogen increased with nearly a factor 10 during measurement in July 2003 and decreased to a concentration of about 6mg/l at the end of last year. Phosphate increased 5 times in July 2003 and 15 times at the end of 2005. The concentration of DOC first increased with a factor 2 but decreased in the last period to 52mg/l. It cannot be derived from the determination of DOC whether all present carbon forms a suitable source for the decomposition of VOCs. Experience and data from literature indicate that the nutrients, administered through the electrode wells and infiltration filters, are quickly decomposed and that they have a positive influence on the decomposition process of VOCs. The data show clearly that the concentration of these nutrients and electron donors increases, caused by the infiltration and dispersion of nutrients by the electrokinetic biofence. 

Kjeldahl method based on the nltrogen-to-protein factor 6.25. 

Protein contents are calculated from Kjeldahl nitrogen values by applying the factor 6.25 as the nitrogen equivalent for protein. However, the nature of the nitrogenous components must be elaborated by further research. In a discus-... 

Total nitrogen of the AIS was determined by a semi-micro Kjeldahl procedure on a 0.50 g sample and the protein content calculated using the factor 6.25. The ash content was determined on a 0.5 g sample of the AIS ignited In a muffle furnace at 550 C for 16 hours. 

Fume hoods are intended to be used to house activities that should not be done on an open bench because of the potential hazard which the activities represent, usually the generation of noxious fumes. The ability of fume hoods to capture and retain fumes generated within them is especially vulnerable to air movement, either due to traffic or other factors such as the location of air system ducts, windows, doors, or fans. Clearly, they should be located, as in the standard laboratory module, in a remote portion of the laboratory selected for low traffic and minimal air movement. Other fume generating apparatus, such as Kjeldahl units, should also be placed in out of the way places where errant air motion will not result in dispersion of the fumes generated into more heavily occupied areas of the room. A point that needs to be considered is the work habits of laboratory employees. Data on the possible health effects of long-term exposures to the vapors from most laboratory chemicals is relatively scant, although there are beginning to... 

Busch et al. (1971) purified Eu by a fractionating column arrangement. The baffles of the column were at different temperatures due to their distance from the high frequency induction coil which heated the crucible containing the crude metal. The temperature of the various baffles was not reported. Eu with total impurities less than 0.02 at.% was obtained as determined by mass spectroscopy. The reason for the higher purity of this Eu compared to the Eu purified by sublimation (see table 2.5) is not clear but could be due to differences in analytical techniques, since the purification methods are essentially the same. The mass spectrometer method used by Busch et al. (1971) to analyze the Eu was not checked against standard methods such as vacuum fusion for H, Kjeldahl for N, combustion for C and neutron activation for O. As explained in ch. 37C, the mass spectrometric results for these impurities could be in error by a factor of 10. 

Fresh natural rubber latex contains 1-2% of proteins. The total protein content can be estimated by the semi-micro Kjeldahl method using the formula nitrogen content x 6.25. When a field natural rubber latex is centrifuged, about one-quarter of these proteins is adsorbed on the surface of rubber particles, another quarter in the bottom fraction and half of them in the serum fraction. The serum phase of natural rubber latex has been shown to contain proteins different from those of rubber particles in terms of their molecular weights, with those in the serum phase fall in the region of 6 to more than 200 kDa, while the major proteins of rubber particles are 14.5 and 29 kDa, which are similar to rubber elongation factor and hevamines, respectively. ... 

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