Supernatant liquors

In a 2-1. three-necked round-bottomed flask, equipped with a mechanical stirrer (Note 1), reflux condenser, and dropping funnel, are placed 30 g. of pure 2-nitrofluorene, m.p. 157° [Org. Syntheses, Coll. Vol. 2, 447 (1943)], and 250 ml. of 95% ethanol. After warming to 50° on a steam bath, 0.1 g. of palladized charcoal catalyst (previously moistened with alcohol) is added (Note 2) and the stirrer is started. About 15 ml. of hydrazine hydrate is added from the dropping funnel during 30 minutes (Note 3). At this point an additional 0.1 g. of catalyst (previously moistened with alcohol) is added and the mixture is heated until the alcohol refluxes gently. After 1 hour the nitrofluorene has dissolved completely and the supernatant liquor is almost colorless. 

The sample preparation was very simple the sample was centrifuged to remove plant cell residues and 10 pi of the clear juice was placed on the column. This type of separation is common with fruits, vegetables and juices and samples can be obtained by preliminary homogenizing the total tissues and then centrifuging. If it is suspected that the residue still contains significant quantities of the substances of interest, then it can be washed with water or if necessary with solvents and the washings combined with the separated supernatant liquor. The results obtained are shown in figure 15. 

The sodium chloride is very finely divided and quickly clogs the pores of the filter paper. The mixture should be allowed to stand for a time before filtration to allow the salt to settle the clear supernatant liquor can then be filtered rapidly. 

Successful methods entail precipitation of the amylose from solution as an insoluble complex, which is removed by high-speed centrifuging the amylopectin is isolated from the supernatant liquor by precipitation with alcohol or, more satisfactorily, by freeze-drying. (Precipitation with alcohol does not always appear to be quantitative, and the physical form of the product obtained by freeze-drying is more satisfactory for subsequent dissolution and esterification.) The amylose can then be further purified by reprecipitation with the same or, preferably, a different complexing agent. 

It is often important to examine the solids which can be isolated from the supernatant liquors obtained during a fractionation, as it would appear that subfractionation of amylose can occur.28... 

During a study of the biosynthesis of pectin substances, a sensitive micromethod for the assay of pectinesterase activity was developed111 that uses a biosynthetically prepared [14C] methyl-labelled pectin as the substrate after enzymic de-esterification, the substrate remaining is precipitated with an excess of methanol and, after centrifugation, the [14C]methanol present in the supernatant liquor is counted in a liquid scintillation counter in order to assess the pectinesterase activity. 

Another method is based on the same principle,112 in which the [14C]labelled methyl ester of D-galacturonan is prepared by esterification of pectic acid with [,4C]diazomethane. In the course of the enzymic de-esterification, aliquots are removed, and the unreacted substrate is precipitated with acidified ethanol or 1-propanol. After centrifugation, the labelled methanol in the supernatant liquor is determined in a liquid scintillation counter. An advantage of this method lies in the possibility of using, as substrates, short-chain oligo-D-galactosiduronates partially esterified with [14C]methanol. These substrates, beginning with the trisaccharide, are not soluble in 1 4 80% phenol-diethyl ether, which is used for the extraction of enzymically released, labelled methanol. 

HYAN [Hybrid anaerobic] A process for treating the supernatant liquor from sewage sludge treatment plants by anaerobic digestion. The methane produced is burnt to provide heat for the treatment plant and to destroy odors. Developed by a Canadian consortium and operated at the Lakeview Water Pollution Control Plant, Mississauga, Ontario, from 1991. 

Cells (C), or supernatant liquor (S). b YCV, Yeast nitrogen base-Casamino acids-Vitamins. M, Synthetic medium. d BHI, Brain-heart infusion. Sab, Sabouraud.1 B, Mariat s medium. 

Second, in earlier experiments samples of sludge were centrifuged, and the supernatant liquor discarded and replaced by tap water, before being used in the standard odour potential test. Some re-extraction of odour from the samples was rapidly found. 

Results are expressed as percentages of the activity of the whole sucrose homogenate. All assays were done in the presence of Triton X-100, with p-nitrophenyl a-D-mannoside as substrate. Fractions I, nuclei and unbroken cells II, mostly mitochondria III, mostly microsomes and IV, final supernatant liquor. 

For the assay of a-D-mannosidase, the incubation mixture employed in our laboratory contained 0.5 ml of M acetate buffer at a pH appropriate for the particular enzyme preparation, 1.5 ml of 16 mM p-nitrophenyl a-D-mannopyranoside, 1.5 ml of water (which could be replaced by other additives as required), and 0.5 ml of suitably diluted, enzyme preparation. After 1 hour at 37°, the reaction was terminated, and the color was developed by adding 4 ml of 0.4 M glycine-sodium hydroxide buffer, pH 10.5. The mixture was centrifuged for 15 minutes at 1500 g, and the color intensity of the liberated p-nitrophenol (25-150 fig) in the supernatant liquor was measured on a Spekker photoelectric absorptiometer, with use of Ilford No. 601 violet filters having maximal transmission at 430 nm, and a 1-cm light path. Separate control-experiments for enzyme and sub-... 

Enzymic transfer of D-xylose from uridine 5 -(D-xylopyranosyI-HC pyrophosphate) to L-serine residues of endogenous protein acceptors from (a) a cell tumor of the mouse188 and (b) chick-embryo cartilage189 occurs in cell-free extracts of both of these tissues, in the absence of biosynthesis of protein. The enzyme preparations employed were from the supernatant liquor, although activity was also present in the insoluble fractions. In these two types of tissue, the acceptors are heparin and chondroitin sulfate, respectively, but the presence of other D-xylose-containing glycoproteins in ascites fluid from... 

If ammonium carbamate be treated with less than its eq. of calcium chloride, it soon gives a precipitate, and the filtered soln. gives no further precipitation when heated. The reaction is the same as when calcium chloride is added in excess. An ammoniacal soln. of calcium chloride gives an instantaneous but slight precipitate when treated with an excess of a soln. of ammonium carbamate. The precipitate increases slowly on standing, and next day, when boiled, the supernatant liquor gives a copious precipitate. The immediate precipitation is presumably due to the presence of ammonium carbonate, and the subsequent precipitation is due to the slow conversion of carbonate to carbamate in the presence of free ammonia. Hence, an ammoniacal soln. of calcium chloride gives an immediate precipitation with an excess of ammonium carbonate and a very slow precipitation with an excess of the carbamate. 

Equations can be formulated for many complex patterns, combinations of mixed and plug flow, with decanting of supernatant liquor that contains the smaller crystals and so on. A modification to the CSTC model by Jandc and Garside (1976) recognizes that linear crystal growth rate may be size-dependent in one instance... 

Solvents differ in their capacity to effect fractionation. Thus, in a study of the polyaddition of levoglucosan, 83-90% ethanol gave a 7% yield of a fraction of Mw 22,750 and addition of one volume of acetone to the supernatant liquor gave a 7% yield of a fraction having213 Mw 38,650. Such differences in solvents may be useful, for example, in separating branched from unbranched polymers within a particular molecular-weight range. 

If MF is mixed with LA, treat the mixt with 20% Na thiosulfate as described above and allow the sludge to settle overnight. Discharge the supernatant liquor into a sump and treat the residue with 10% NaOH soln as described under Azide, Lead. Allow the mixt to stand overnight, discharge the liquid into a sump and dispose of the sludge... 

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