摘要:

Abstract107 species and 8 species varieties belonging to 44 genera were collected from combine harvester wheat and sorghum dusts (35 genera and 91 species + 4 varieties) and from the atmosphere of their hay sites (26 genera and 69 species + 4 varieties) on glucose‐ and cellulose‐CZAPEK's Dox agar at 28 °C and 45 °C. The mycoflora of wheat and sorghum dusts were basically similar on the two types of media and the most common fungi were:Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus. A. svdowii, A. terreus, Cochliobolus spicifer, Emericella nidulans, Fusarium moniliforme, Penicillium chrysogenum, P. duclauxii, P.funiculosumandP. oxalicum.Truly thermophilic species were frequently encountered from the two substrates:Chaetomium thermophilum, Humicola griseavar. thermoidae, H. insolens, Malbranchea pulchella var.sulphurea, Rhizomucor pusillus, Sporotrichum thermophilum, Talaromyces thermophilus, Thermoascus thermophilusandThermomyces lanuginosus.The airborne fungi in the two atmospheres were basically similar and the most prevalent species were members ofAlternaria(1 species),Aspergillus(18 species + 2 varieties),Chaetomium(2 species),Cochliobolus(3 species),Emericella(3 species + 2 varieties),Fusarium(3 species),Mucor(1 species),Penicillium(14 species) andStachybotrys(1 spe

ISSN:0233-111X    

DOI:10.1002/jobm.3620300702

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620300704

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

AbstractUsing the proton extrusion of growing yeast cultures (calculated from the alkali consumption required to maintain a constant pH‐value) it is possible to describe the growth of yeasts and the growth‐related substrate consumption on‐line and to do so more exactly than by determining these values with usual off‐line methods. In batch experiments withCandida maltosain a mineral salt medium clear linear relationships could be demonstrated between the proton extrusion nH+and the increase of biomass concentration (determined as dry weight, optical density and protein according to a modified LOWRY‐method) as well as substrate consumption (n‐hexadecane and NH+4as the C‐ and N‐sources respectively). The biochemical basis of the proton extrusion seems to be connected with the NH+4‐metabolism. The simple on‐line registration of the proton extrusion offers various possibilities to use this value for control of fer

ISSN:0233-111X    

DOI:10.1002/jobm.3620300705

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe proton extrusion of growing yeast cultures was demonstrated to be a very exact and reliable on‐line parameter for the description of the growth of yeasts and substrate consumption in batch fermentation processes. Using this parameter we were able to build up a minimized fermentation apparatus (working volume about 90 ml) which permits the description of growth from substrate amounts of 5 to 50 mg quantitatively in fed‐batch fermentation processes.Using various yeast strains it was demonstrated for nitrogen‐free carbon sources such as hydrocarbons and carbohydrates that1. the course of the proton extrusion indicates qualitatively whether any given carbon source can be utilized as a growth substrate or not, and that2. the amount of proton extrusion is a reliable and reproducible quantitative parameter for growth on the tested substrate.This minimized fermentation apparatus offers advantages and possibilities to detect growth of microorganisms from very small substrate amounts in submerged cul

ISSN:0233-111X    

DOI:10.1002/jobm.3620300706

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620300707

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

AbstractA haploid, glucoamylase‐producing strain ofSaccharomyces diastaticuslacking the POF gene and thus unable to produce phenolic off‐flavour in beer was constructed by classical genetic techniques. Protoplast fusion was performed between this strain and a brewing polyploidSaccharomyces uvarumstrain. Some clones derived from fusion products can produce low‐carbohydrate beer of acceptable fl

ISSN:0233-111X    

DOI:10.1002/jobm.3620300708

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620300710

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe uptake of L‐carnitine byEscherichia coli044 K 74 which is able to metabolize L‐carnitine to γ‐butyrobetaine under anaerobic conditions was studied. The uptake system ofE. coliwas induced in the presence of L‐carnitine or crotonobetaine. The optimum influx of L‐carnitine was found to take place at 37 °C in phosphate buffer, pH 7.5. On the basis of the temperature dependence of the uptake rate an activation energy of 53.5 kJ/mol was estimated. The transport of L‐carnitine was energy dependent. The kinetics of L‐carnitine entry followed the MICHAELIS‐MENTEN relationship yielding aKmvalue of 5.3 · 10‐4M and aVmaxof 154 nmol/min · mg protein. The transport system showed considerable structural specifity for trimethylamine carboxylic molecules. The results suggest thatE. colipossesses an inducible, active and carrier‐mediated uptake

ISSN:0233-111X    

DOI:10.1002/jobm.3620300711

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

AbstractA new method of dissimilatory nitrite reductase (cytochromecd1) isolation from the periplasmic fraction of anaerobically grown cells of the bacteriumParacoccus denitrificanswas developed, using ionex and gel permeation chromatography with FPLC system (PHARMACIA, Sweden). In experiments with isolated enzyme it was shown that through a nitrite reduction, catalysed by this enzyme, a substance (presumably nitric oxide) was formed which at submicromolar concentrations inhibited terminal cytochrome oxidase of the respiratory chain of the same bacterium. These results help to explain formerly observed sensitivity of bacterial oxidase activity to NO‐2and the mechanism of switching the electron flow from O2to nitrogen terminal acceptor

ISSN:0233-111X    

DOI:10.1002/jobm.3620300712

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY

摘要:

Abstract92% of the cellular proteins from the osmotically fragile strainSacch. cerevisiae211 (MATasrbl srb2 tsl) were extracted by one passage in a high pressure disintegrator at 650 atm. After isoelectric precipitation, 60.1% of the proteins were isolated. The protein extract was rich in proteins (60–70%) but also contained 12–13% nucleic acids and 13–14 % carbohydrates. Mild conditions were created for simultaneous reduction of nucleic acids and carbohydrates in the lysate prior to precipitation of proteins. Under these conditions the amount of nucleic acids in the protein extract was reduced to 2 %, and that of the carbohydrates to 5.7 %. As a result of the whole procedure on a pilot scale, 1 1 culture ofSacch. cerevisiae211 grown in molasses based nutritional medium yielded 1 g protein extract. The applicability of this protein extract for nutritional purposes was demonstrated by determination of its amino acid composition, acute toxicity tests withTetrahymenapyriformis and short‐term animal nutrition tests. The results showed that the protein extract is a suitable source of SCP for nutritional p

ISSN:0233-111X    

DOI:10.1002/jobm.3620300713

出版商:Wiley‐VCH    

年代:1990

数据来源: WILEY