SVIBOR - Papers quoted in CC - project code: 4-07-034
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Papers quoted in Current Contents on project 4-07-034
Quoted papers: 4
Other papers: 26
Total: 30
Title: Enzymatic Hydrolysis of Protein During Barley Spent Grains
Mashing
- Authors:
- Marković, Ivan (28725)
- Deponte, Romeo
- Marić, Vladimir
- Johanides, Vera
Journal: Process Biochemistry
Number: 5
ISSN: 0032-9592
Volume: 30
Year: 1995
Pages: from 411 to 419
Number of references: 35
Language: engleski
Summary: High nitrogen barley syrup (HNBS) was obtained by mashing
barley spent grains with neutral proteinase. The total nitrogen to
carbohydrate ratio in the HNBS was three times higher than in typical
barley syrup. In order to enhance the liberation of free amino acids, the
spent grains were hydrolysed simultaneously with proteinase and barley
peptidase extract; the a-amino to total nitrogen ratio increased from 11.4
to 14.6%. During mashing with neutral proteinase only. Data analysis by
means of the modified Foster-Niemann equation suggested that endopeptidase
inhibitors, possibly present in the peptidase extract, caused the decrease
of protein solubilization rate. The isolation of the bacterial proteinase
inhibitors from peptidase extract indicates that they affected the protein
solubilization process.
Keywords: spent grains, berley syrup, protein, hydrolysis, proteinase, barly
Title: Coordination of sucrose uptake and respiration in the
yeast Debaryomyces yamadae
- Authors:
- Kaliterna, Janko (186973)
- Weusthuis, Ruud A.
- Castrillo, Juan I.
- van Dijken, Johannes P.
- Pronk, Jack T.
Journal: Microbiology
ISSN: 1350-0872
Volume: 141
Year: 1995
Pages: from 1567 to 1574
Number of references: 25
Language: engleski
Summary: Screening in batch cultures identified Debaryomyces yamadae
as a yeast that exibits the Kluyver effect for sucrose: thisdisaccharide
can be respired but, even under oxygen-limited conditions, alcoholic
fermemtation of sucrose does not occur. Ethanol, glycerol and arabitol were
the main fermentation products during oxygen-limited growth on glucose in
chemostat cultures. None of these fermentation products were produced in
oxygen-limited chemostat cultures grown on sucrose and the fraction of the
sucrose that could not be respired remained unused in the culture medium.
This absence of alcoholic fermentatin was not due to respression of the key
fermentative enzymes pyruvate decarboxylase and alcohol dehydrogenase. In
contrast to some other yeastthat exibit a Kluyver effect, D. yamadae did
not exibit a performance for ethanol in batch cultures grown on mixtures of
ethanol and sucrose. Sucrose metabolism in D. yamadae involves
intracellular hydrolysis by an a-glucosidase. Incubation of weakly buffered
cell suspensions with sucrose led to a rapid transient alkalinization,
indicating the presence of a sucrose-proton symport system. The apparent
substrate saturation constant of the sucrose-uptake system was 0.2 mmol
l-1. Sucrose-dependent alkalinization rates were much lower in samples from
oxygen-limited cultures than in samples from aerobic cultures. Transient
responses of D. yamadae to oxygen limitation were investigated by applying
a sudden decrease in the oxygen feed to aerobic sugar-limited chemostat
culrures. In glucose-grown cultures, this led to alcoholic fermentation and
no significant accumulation of sugar occured after the switch. In
sucrose-limited cultures, sugar accumulation occurred instantaneosly after
the switch, and ethanol formation was virtually absent. The results
indicate that the Kluyver effect for sucrose in D. yamadae, i.e. the
adjustment of the glycolytic flux to the cells' respiratory capacity, is
effected by rapid down-regulation of the capacity of the sucrose carrier
under oxygen-limited conditions.
Keywords: alcoholic fermentation, Kluyver effect, sucrose metabolism, invertase, transport
Title: High-cell-density cultivation of yeasts on disaccharides
in oxygen-limited batch cultures
- Authors:
- Castrillo, Juan I.
- Kaliterna, Janko (186973)
- Weusthuis, Ruud A.
- van Dijken, Johannes P.
- Pronk, Jack T.
Journal: Biotechnology and Bioengineering
Number: x
ISSN: 0006-3592
Volume: x
Pages: from x to x
Number of references: 25
Summary: Many facultatively fermentative yeast species exibit a
"Kluyver effect": even under oxygen-limited growth conditions, certain
disaccharides that support aerobic, respiratory growth are not fermented.
This paper investigates the applicability of this phenomenon for
high-cell-density cultivation of yeast. In glucose-grown batch cultures of
Candida utilis CBS 621, the onset of oxygen limitation led to alcoholic
fermentation and, consequently, a decrease of the biomass zield on sugar.
In maltose-grown cultures, alciholic fermentation did not occur and
oxygen-limited growth resulted in high biomass concentrations (90 g dry
weight.l-1 from 200 g.l-1 maltose monohydrate in a simple batch
fermentation). It was subsequently investigated whether this principle
could also be applied to Kluyveromyces species exhibiting a Kluyver effect
for lactose. In oxygen-limited, glucose-grown chemostat cultures of K.
wickerhamii CBS 2745, high ethanol concentrations and low biomass yields
were observed. Conversely, ethanol was absent and biomass yields on sugar
were high in oxygen-limited chemostat cultures grown on lactose. Batch
cultures of K. wickerhamii grown on lactose exibited the same growth
characteristics as the maltose-grown C. utilis cultures: absence of ethanol
formation and high biomass yields. Within the species K. marxianus, the
occurrence of a Kluvyer effect for lactose is strain dependent. Thus, K.
marxianus CBS 7894 could be grown to high biomass densities in
lactose-grown cultures, whereas strain CBS 5795 produced ethanol after the
onset of oxygen limitation and, consequently, yielded low amounts of
biomass. Since use of yeast strain exibiting a Kluyver effect obviates the
need for controlled substrate-feeding strategies to avoid oxygen
limitation, such strain should be excellently suited for the production of
biomass and growth-related products from low-cost disaccharide-containing
feedstocks.
Keywords: Kluyveromyces, Candida utilis, Kluyver effect, chemostat, biomass, whey
Title: Transient Responses of Candida utilis to Oxygen
Limitation: Regulation of the Kluyver Effect for Maltose
- Authors:
- Kaliterna, Janko (186973)
- Weusthuis, Ruud A.
- Castrillo, Juan I.
- van Dijken, Johannes P.
- Pronk, Jack T.
Journal: Yeast
ISSN: 0749-503x
Volume: 11
Year: 1994
Pages: from 317 to 325
Number of references: 19
Language: engleski
Summary: The Facultatively fermentative yeast Candida utilis exibits
the Kluvyer effect for maltose: this disaccharide is respired and
assimilated but, in contrast to glucose it cannot be fermented. To study
the mechanism of the Kluvyer effect, metabolic responses of C. utilis to a
transition from aerobic sugar-limited growth to oxygen-limited conditions
were studied in chemostat cultures. Unexpectedly, the initial response of
maltose-grown cultures to oxygen limitation was very similar to that of
glucose-grown cultures. In both cases, alcoholic fermentation occurred
after a lag phase of 1 h, during which glycerol, pyruvate and D-lactate
were the main fermentation products. After ca. 10 h the behaviour of the
maltose- and glucose-grown cultures diverged: ethanol disappeared from the
maltose-grown cultures, whereas fermentation continued in steady-state,
oxygen-limited cultures grown on glucose. The disappearance of alcoholic
fermentation in oxygen-limited chemostat cultures growing on maltose was
not due to a repression of the synthesis of pyruvate decarboxylase and
alcohol dehydrogynase. The results demonstrate that the Kluyver effect for
maltose in C. utilis does not reflect an inability of this yeast to
fermentmaltose, but is caused by a regulatory phenomenon that affects a key
enzyme in maltose metabolism, probably the maltose carrier. The observed
kinetics indicate that this regulation occurs at the level of enzyme
synthesis rather than via modification of existing enzyme activity.
Keywords: yeast, Candida utilis, alcoholoc fermentation, Kluvyer effect, oxygen limitation
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