D. A. John Wase

Batch nickel removal from aqueous solution by sphagnum moss peat

Abstract The batch adsorption of Ni(II) onto sphagnum moss peat has been studied. The reaction was pH dependent, the optimum range being 4.0–7.0. Langmuir and Freundlich isotherms, established for various initial nickel concentrations and for a range of pH values, were used to obtain a single relationship between initial metal concentration, metal removal, and initial pH. The latter was found to control efficiency of nickel removal. Kinetic data suggested involvement of a chemical rate-limiting step, and a predictive relationship was derived relating nickel removal to peat dose. In comparison with other metals, nickel removal is poor, and possible reasons are discussed.

Co-Digestion of Cattle Slurry and Waste Milk under Shock Loading Conditions

Anaerobic digestion of cattle slurry has become a well established practice. In recent years disposal of waste milk in the UK has been the cause of many pollution incidents. This paper describes the co-digestion of cattle slurry and waste milk under shock loading conditions in 1 dm 3 laboratory digesters. Methane concentration in the biogas of all digesters receiving waste milk additions initially dropped, but quickly recovered to above previous levels. The methane production rate (dm 3 methane day -1 ) was most elevated in those digesters receiving the greatest loading of waste milk; however, initial depression of biogas methane concentration was also greatest in this system.

Variation of intracellular sodium and potassium concentration with changes in agitation rate for chemostat-cultivatedEscherichia coli

SummaryEscherichia coli was continuously cultivated in a disc turbine agitated laboratory fermenter at constant dilution rate under conditions of carbon limitation. Agitation rate (impeller speed) was varied over the range 600 to 1500 rev. min-1. As previously reported, the mean cell volume was found to increase linearly with increase in agitation rate, whereas total cell counts and dry cell weights remained constant. Measurements of intracellular sodium and potassium concentration showed that these both increased as the cell volume increased: the potassium content was about twenty times the sodium content and the intracellular content of each ion doubled over the range of agitation rates tested.

The susceptibility to ultrasonic disintegration ofKlebsiella pneumoniae NCTC 418

SummaryThe resistance to ultrasonic disintegration of cells ofKlebsiella pneumoniae grown at various dilution rates in continuous culture decreased with increasing cell size. Whilst this effect could be related to the cell wall content of the specimens, no direct relationship between the cell wall strength and the rigidity-conferring peptidoglycan was observed.

Some comparisons of cellulases from two different strains of Aspergillus fumigatus

Abstract Michaelis-Menten kinetics for exoglucanase, endoglucanase and β-glucosidase activities from two different strains of Aspergillus fumigatus were compared in the absence and the presence of ammonium ions. Inhibitory effects, evident in only one strain, were quantified, suggesting non-competitive inhibition for endoglucanase and β-glucosidase, but competitive inhibition of exocellulase. Possible reasons are discussed.

Alkaline stability of the oligosaccharides present in beet medium invert sugar

Abstract The stability of the components of beet medium invert sugar, d -glucose, d -fructose, sucrose, and oligosaccharides, in the eluent used for anion-exchange high-performance liquid chromatography (HPLC) analysis with pulsed amperometric detection has been determined. The monosaccharides undergo degradation when stored in 100 m m sodium hydroxide but the degradation products produced elute before the beet medium invert sugar fingerprint oligosaccharides. Sucrose and the fingerprint beet medium invert sugar oligosaccharides do not produce detectable degradation products when stored under similar conditions. The presence of sodium acetate, the eluting salt in the HPLC method, does not alter the degradation product spectrum. The fingerprint peaks in the oligosaccharide region, are components of beet medium invert sugar and not artefacts of the anion-exchange HPLC method; they are stable under the HPLC analysis conditions used.

Oxygen uptake studies on various sludges adapted to a waste containing chloro-, nitro- and amino-substituted xenobiotics

Abstract Although containing very low concentrations of organics, triaminotrinitrobenzene (TATB) effluent still appeared toxic in shake-flask experiments. Few toxicity effects showed in model activated-sludge plants, provided that these contained suitably adapted organisms, and were run on phenolic waste or phenol as a basic carboniferous load. Oxygen uptake studies indicated that the metabolic processes within the sludge population appeared unusual, and that degradation of TATB effluent required a sludge which was specially adapted.

Inhibitor of β-d-glucosidase and endo-1,4-β-d-glucanase produced by Aspergillus fumigatus IMI 255091

Abstract Inconsistencies in assays of fermentation broths of Aspergillus fumigatus IMI 255091 were observed for endo-1,4-β- d -glucanase [1,4-(1,3;1,4)-β- d -glucan 4-glucanohydrolase, EC 3.2.1.4] and β- d -glucosidase (β- d -glucoside glucohydrolase, EC 3.2.1.21). Dilution of the original sample appeared to enhance activity. These enzymes were apparently not adsorbed by sintered microporous inorganic spheroids specially fabricated for protein adsorption. The adsorbents removed other proteins, including material shown to be of low molecular weight and assumed to be an inhibitor, permitting considerably enhanced activity.

Identification of the fructo-oligosaccharides common to beet medium invert sugar and pyrolysed sucrose

Abstract Chromatography and enzymolysis have been used to identify the primary oligosaccharides common to beet medium invert sugar and pyrolysed sucrose. Anion exchange and reversed phase HPLC showed the two materials to contain a similar spectrum of primary oligomers, although at a much higher level in pyrolysed sucrose. Confirmation of the similarity was obtained by reversed phase fractionation and anion exchange HPLC analysis of the individual fractions. Gel filtration chromatography was used to estimate the size of the oligomers with gel filtration fractionation of the sample of beet medium invert sugar and subsequent anion exchange HPLC analysis of the fractions, confirming that the primary oligosaccharides elute in the same position as the starch trisaccharide maltotriose. Enzymolysis, using invertase EC 3.2.1.26, of beet medium invert sugar and pyrolysed sucrose, and subsequent analysis of the digest using anion exchange HPLC, showed that four of the oligosaccharides were cleaved by the enzyme, indicative of a terminal β - D -fructofuranoside residue in each. Another two oligosaccharides were stable to the enzyme, and therefore do not possess the terminal β - D -fructofuranoside feature. One additional oligosaccharide appeared during the enzymolysis. From the enzymolysis and chromatographic data and by comparison of the elution positions of the primary oligosaccharides with those of reference standards it was concluded that the primary oligosaccharides present in both beet medium invert sugar and pyrolysed sucrose are the kestoses, l-kestose, 6-kestose, and neokestose and their α-anomers, iso -1-kestose, iso -6-kestose, and iso -neokestose. Although the kestoses may be the products of enzymic action on sucrose the iso -kestoses are not produced and therefore must originate through a thermal process. These oligosaccharides used as indicators for the detection of beet medium invert sugar extension of orange juice are unlikely to occur naturally in oranges as orange invertase has α - D -glucosidase activity and therefore oligosaccharides produced in situ would have glucose linked to sucrose rather than the kestoses and iso -kestoses, produced by β - D -fructosidase or thermolysis, where fructose is linked to sucrose.

Influence of iron-bearing natural humic compounds on the physiology of escherichia coli in continuous culture

Abstract The mean cell volume of continuously cultivated Escherichia coli varied according to the source of water used in the preparation of media. For tap water, cells were always larger than those cultured under corresponding conditions in distilled water; deionised water gave intermediate results. The mean cell volume was constant and independent of variation in agitation rate when distilled water was used. With both deionised-water and tap-water media, the mean cell volume increased sharply with an increase in agitation rate. The magnitude of this effect was greater with tap water than with deionised water. Solids recovered from Birmingham tap water contained relatively high levels of iron, together with phosphorus and potassium. Solids recovered from deionised water also contained appreciable amounts of iron. The iron was assumed to be in the form of organometallic complexes with the humic materials known to exist in Birmingham tap water. Fulvic acids were therefore extracted from Birmingham tap water, but had no effect on the mean volumes of the E. coli cells cultured in a distilled-water-based medium to which the recovered fulvic acids had been added. However, when iron salts were also added, these partially restored the effects previously observed with tap water. It is concluded that the humic chelates in natural waters can act as iron carriers for a range of microorganisms.