ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02541.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02542.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

This study describes the isolation of a phage, using mitomycin C and u.v. light, from each of four strains (HD67, HD130, HD228 and HD248) ofBacillus thuringiensisH‐serotype 7 (var. aizawai). It also describes the isolation of two indicator strains (12.13 and HD 102) for these phages (φHD67, φHD130, φHD228 and φHD248) and the ideal conditions, using these indicator strains, for maximum phage produ

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02543.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A factorial design was used to determine the main effects and interactions of pH (3.6, 3.8 and 4.0), SO2(25 and 50 mg/l), ethanol (7%, 10% and 13%, v/v) and temperature (15°C and 25°C) on the growth of 54Leuconostoc oenosstrains. These differed greatly in their ability to survive adverse conditions. Under the test conditions, temperature had a profound effect on growth. The power pH values of 3.6 and 3.8 had a marked inhibitory effect on growth, as did at the lower temperature of 15°C. The higher concentrations of SO2(50 mg/l) and ethanol (13%) had the greatest inhibitory effect on growth, and with a synergistic effect when both SO2and ethanol were added to the test medium. Based on these results, five strains were selected that were best capable of surviving the adverse conditions studied. These strains will be used for further study on the induction of malolactic fermentation in wi

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02544.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Fifty‐three strains of Micrococcaceae isolated from Spanish sheep's milk cheeses were subjected to numerical analysis using 43 unit characters. At the 80% similarity level (SSM) nine clusters (49 strains) were observed. At the 53% similarity level (SJ) nine clusters were also found. Cluster composition was not markedly affected by the coefficient used. Novobiocin‐resistant, coagulase‐negative staphylococci formed clusters of closely related species. However, novobiocin‐sensitive, coagulase‐negative strains fell into heterogeneous groups. The test that best separated the nine groups formed with both coefficients (SSMandSJ) was urease production. Aesculin hydrolysis, haemolytic activity (SSM), oxidation of mannose and phosphatase production were also useful c

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02545.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Bacteria grew to viable populations of 108–109cfu/g during the fermentation of soybeans into tempe with the fungus,Rhizopus oligosporus. Bacillus pumilusandB. breviswere the predominant bacterial species, reaching populations of approximately 108cfu/g during the 48 h fermentation. Species ofStreptococcus faecium, Lactobacillus casei, Klebsiella pneumoniaeandEnterobacter cloacaealso contributed to the fermentation and achieved populations of 106–107cfu/g. and accepted 25 May

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02546.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Single starter cultures were used to ferment cassava for fufu production in a process which involved steeping seeded cassava tubers in water for 96 h. The cultures used includeBacillus subtilis, Klebsiellasp.,Lactobacillus plantarumandCandida krusei. Lactobacillus plantarumexhibited the highest acid producing ability, decreasing the pH of the cassava tubers from 6.0 to 3.62, with a corresponding increase in total titratable acidity (TTA) from 0.072% to 0.250% during the 96 h fermentation period. The effected changes in pH and TTA by other organisms ranged respectively from 5.03 and 0.125% forKlebsiellasp., 5.07 and 0.126% forC. krusei, to 5.20 and 0.128% forB. subtiliswithin the period.Lactobacillus plantarumgrew better than other cultures singly inoculated. While all the cultures were found to contribute to the characteristic odour of fufu,C. kruseieffected the highest perceived characteristic odour. Also, the cultures variably caused softening of the tubers, withB. subtilisshowing the highest softening capability.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02547.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Bacillus licheniformis, an indigenous strain from high silica‐containing magnesite ore was found to tolerate 250 μg of Si/ml (Na2SiO3.5H2O) in the medium. During growth the bacterium was capable of accumulating about 21 μg of Si/ml within 8 h. The absence of phosphate was highly inhibitory to its growth as well as silicon absorption. A relationship between growth, utilization of Si and its release from magnesite ore is discussed. A feedback inhibition of Si release from the ore has been predic

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02548.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Three exo‐glucanases, two endo‐glucanases and two β‐glucosidases were separated and purified from the culture medium ofAspergillus nidulans.The optimal assay conditions for all forms of cellulase components ranged from pH 5.0 to 6.0 and 50°C and 65°C for exo‐glucanases and endo‐glucanases but 35°C and 65°C for β‐glucosidases. A close relation of enzyme stability to their optimal pH range was observed. All the cellulase components were stable for 10 min at 40–50°C. Exo‐II and Exo‐III (Km, 38.46 and 37.71 mg/ml) had greater affinity for the substrate than Exo‐I (Km, 50.00 mg/ml). TheKmvalues of Endo‐I and Endo‐II (5.0 and 4.0 mg/ml) and their maximum reaction velocities (Vmax, 12.0 and 10.0 IU/mg protein) were comparable. β‐Glucosidases exhibitedKmvalues of 0.24 and 0.12 mmol andVmaxvalues of 8.00 and 0.67 IU/mg protein. The molecular weights recorded for various enzyme forms were: Exo‐I, 29000; Exo‐II, 72500; Exo‐III, 138000; Endo‐I, 25000; Endo‐II, 32500; β‐Gluco‐I, 14000 and β‐Gluco‐II, 26000. Exo‐ and endo‐glucanases were found to require some metal ions as co‐factors for their catalytic activities whereas β‐glucosidases did not. Hg2+inhibited the activity of all the cellulase components. The saccharification studies demonstrated a high degree of synergism among all t

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02549.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Incubating cultures ofEscherichia coliwith propionic acid (5 mmol/l) or formic acid (10 mmol/l) at pH 5.0 produced bacteriostasis lasting 30 and 120 min respectively. During this time rates of RNA, DNA, protein, lipid and cell wall synthesis were reduced. Growth resumed after continued incubation in the presence of acid, but cells from acid‐treated cultures were larger than controls. DNA synthesis was particularly sensitive to the presence of the propionic or formic aci

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1990.tb02550.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY