摘要:

The fermentation of soya bean for ‘daddawa’ production in Nigeria is carried out by bacteria.Bacillus subtilisandBacillus pumiluswere consistently isolated in fermentations lasting 4

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01902.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Twelve strains of meat lactic starter cultures(Pediococcusspp. andLactobacillus plantarum)were found to produce hydrogen peroxidein vitro.The (cumulative) amounts of H2O2produced were measured through the peroxidative action of catalase on H2O2and oxidation of added formate to CO2by the H2O2‐catalase complex formed. There was a problem in building a calibration curve for converting values of formate oxidation into amounts of H2O2, either by adding H2O2directly to the assay mixture or having it produced via a glucose‐glucose oxidase sys

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01903.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Proteinases were excreted by strains ofBacillus subtilisduring fermentation of African locust bean cotyledons. Those excreted by one strain were purified and characterized by ammonium sulphate precipitation, ion‐exchange chromatography (IEC), gel filtration, inhibition tests and polyacrylamide gel electrophoresis (PAGE). Three proteinases and an esterase without proteolytic activity were identified. A serine proteinase which showed a high degree of hydrophobicity and a neutral proteinase were present. The third proteinase showed both proteolytic and esterolytic activities, and had multiple electrophoretic mobilities on polyacrylamide ge

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01904.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Trials were conducted to determine thein vivotransferability of plasmid‐mediated antibiotic resistance between two strains of enteric Gram‐positive bacteria. Germfree mice were associated with the donorLactobacillus reuteriDSM 20016 strain, carrying the broad host range pAMβ1 plasmid, and with theEnterococcus faecalisJH2SS recipient strain.Analysis of faecal content of associated mice demonstrated that thein vivotransfer of this plasmid did occur and that frequencies of conjugation were affected by the presence of subtherapeutic levels of antibiotic in the

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01905.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Three bacteriophage tracers were added to 600–1 containers of water and simulated latrine sludge to provide high titres of tracer in aqueous and semi‐aqueous media. After a period of mixing and stabilization, media were removed from the containers with suction hoses coupled to the vacuum pump of one of two sludge suction tankers. Exhaust air from the appliances was sampled by cyclone sampler and assayed for the presence of tracer organisms carried over during the emptying process. In the experiments the appliances were operated at different vacuum pump speeds, drawing both aqueous and semi‐aqueous (simulated sludge) media. Air around one tanker was also sampled during the emptying, under pressure, of the vacuum vessel. The degree of aerosolization and expulsion of tracer bacteriophage by the vacuum appliances was consistently low, regardless of medium and pump air flow. In contrast, the proportion of tracer retained within the appliances was very high, exceeding the proportion expelled by a minimum of 8log10orders of magnitude and a maximum of greater than 11log10orders. The highest total of tracer bacteriophage was recovered during the pressure emptying of the vacuum vessel of one tanker. The results may be used for assessing and comparing potential public health hazards associated with the handling of wastewater sludge by vacuum appli

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01906.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Three tracer experiments employing three different bacteriophage were performed at one groundwater site near Beverley, Humberside. In two of the experiments the bacteriophage were injected into the aquifer by a borehole at a distance of 366 m from the pumping borehole. In the other experiment they were injected at a distance of 122 m. Regular samples were taken of water abstracted at the pumping boreholes as well as from the injection boreholes. The objectives were to: (1) investigate the pattern of bacteriophage recovery from the aquifer; (2) calculate the total number of bacteriophage recovered and the rate of their migration; and (3) detect any differences in bacteriophage behaviour which could be directly related to the morphology of the three bacteriophage. In all experiments the pattern of recovery was similar, exhibiting a peak of high numbers reaching the pumping borehole soon after injection. The highest percentage of original inoculum recovered was 1.9%. In the majority of cases, however, recovery was usually one log10lower than this. The fastest migration rates were very rapid, reaching 2.8 cm/s in one experiment. No variation in percentage recovery or transit time could be directly attributed to morphology of bacteriophage. The most important factor governing the pattern of migration was undoubtedly the hydrogeological conditions.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01907.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Lactobacillus plantarumwas found to produce extracellular polygalacturonase (EC 3.2.1.15.). Maximum enzyme production was obtained in a medium containing 0.5% glucose and 1.5% low methyl‐pectin as inducer at 27°C at an initial pH of 6.8. Enzyme production was strongly inhibited by 5 μmol/l NiCl2, 5 μmol/l CoCl2, 5 μmol/l CuSO4, and 10 μmol/l ZnCl2. MnSO4and MgSO4at 200 μmol/l and 50 μmol/l respectively seemed to enhance enzyme biosynthesis. The optimal pH and temperature for enzyme activity were 4.5 and 30°C respectively. Enzyme production in batch culture accompani

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01908.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The influences of temperature and pH on the survival and growth ofSaccharomyces cerevisiae, Candida stellataandKloeckera apiculatawere examined in the presence of ethanol concentrations between 2.5 and 15% v/v. At 15°C, the maximum concentrations of ethanol permitting the growth ofS. cerevisiae, C. stellataandK. apiculatawere 15%, 11% and 9%, respectively. These maximum concentrations were decreased at 10°C and 30°C. Cells ofS. cerevisiaeshowed no loss in viability when incubated for 12 d at 10°C or 15°C in the presence of 15% ethanol but showed some loss at 30°C. Cells ofC. stellatawere tolerant of 12.5% ethanol at 10°C and 15°C but not at 30°C. Cells ofK. apiculatawere tolerant of 10–12.5% ethanol at 15°C but not at 10°C or 30°C. Sensitivity of the yeast cells to ethanol was marginally increased on decreasing the pH fr

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01909.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

After extraction of food protein from lucerne, the residual fibre was used as a carbon and energy source by the thermophilic actinomycete,Thermomonospora curvata.Induction of catabolic exoenzymes during growth for 7 d on the fibre at 53°C in a mineral salts minimal medium was compared with that on a variety of other inductive substrates. A fibre concentration of 1.5% (w/v) was optimal for total protein secretion. The fibre was a poor substrate for amylase production due to lack of inducer rather than to catabolite repression by soluble sugars released during degradation. β‐Glucosidase release during growth on the fibre was about 10 times that observed in cultures grown on cellobiose or cellulose, but production of other cellulolytic enzymes was about one‐half that produced on cellulose. Pectinolytic activity (measured as polygalacturonate lyase) was equal to that produced on pectin. Cells grown on the fibre released about eight times as much proteinase as those grown on cellulose, but proteolytic activity was transient and decreased rapidly during later growth. Xylanase appeared to be co‐ordinately induced with cellulolytic enzymes; comparable maximal activities, observed during growth on either the fibre or cellulose, were three times that produced on xylan or

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01910.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The effects of two specific inhibitors of sulphate‐reducing bacteria, selenate and molybdate, have been studied by measurement of sulphate uptake and by measurement of the effects of these compounds on growth of the bacteria on a variety of media. The results obtained with selenate are consistent with the view that it acts as a competitive inhibitor of sulphate transport. The results obtained with molybdate show that there is more than one site of action and suggest that the primary effect is also on sulphate transpor

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1988.tb01911.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY