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001-es BibID:	BIBFORM060271
Első szerző:	Karaffa Levente (biotechnológus, egyetemi tanár)
Cím:	A deficiency of manganese ions in the presence of high sugar 5 concentrations is the critical parameter for achieving high yields 6 of itaconic acid by Aspergillus terreus / Levente Karaffa, Rafael Díaz, Benedek Papp, Erzsébet Fekete, Erzsébet Sándor, Christian P. Kubicek
Dátum:	2015
ISSN:	0175-7598
Megjegyzések:	Itaconic acid (IA), an unsaturated dicarboxylic acid with a high potential as a platform for chemicals derived from sugars, is industrially produced by large-scale submerged fermentation by Aspergillus terreus. Although the biochemical pathway and the physiology leading to IA is almost the same as that leading to citric acid production in Aspergillus niger, published data for the volumetric (g L(-1)) and the specific yield (mol/mol carbon source) of IA are significantly lower than for citric acid. Citric acid is known to accumulate to high levels only when a number of nutritional parameters are carefully adjusted, of which the concentration of the carbon source and that of manganese ions in the medium are particularly important. We have therefore investigated whether a variation in these two parameters may enhance IA production and yield by A. terreus. We show that manganese ion concentrations?<?3 ppb are necessary to obtain highest yields. Highest yields were also dependent on the concentration of the carbon source (D-glucose), and highest yields (0.9) were only obtained at concentrations of 12-20 % (w/v), thus allowing the accumulation of up to 130 g L(-1) IA. These findings perfectly mirror those obtained when these parameters are varied in citric acid production by A. niger, thus showing that the physiology of both processes is widely identical. Consequently, applying the fermentation technology established for citric acid production by A. niger citric acid production to A. terreus should lead to high yields of IA, too.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Aspergillus terreus Itaconic acid Fermentation Manganese ions D-Glucose Specificyield Volumetricyield
Megjelenés:	Applied Microbiology and Biotechnology. - 99 : 19 (2015), p. 7937-7944. -
További szerzők:	Diaz, Rafael Papp Benedek Fekete Erzsébet (1975-) (biotechnológus, egyetemi tanár) Karaffa Erzsébet Mónika (1972-) (mikrobiológus, egyetemi tanár) Kubicek, Christian P.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM060272
Első szerző:	Papp Benedek
Cím:	High cell density cultivation of the chemolithoautotrophic bacterium Nitrosomonas europaea / Benedek Papp, Tibor Török, Erzsébet Sándor, Erzsébet Fekete, Michel Flipphi, Levente Karaffa
Dátum:	2016
ISSN:	0015-5632
Megjegyzések:	Nitrosomonas europaea is a chemolithoautotrophic nitrifier, a gram-negative bacterium that can obtain all energy required for growth from the oxidation of ammonia to nitrite, and this may be beneficial for various biotechnological and environmental applications. However, compared to other bacteria, growth of ammonia oxidizing bacteria is very slow. A prerequisite to produce high cell density N. europaea cultures is to minimize the concentrations of inhibitory metabolic by-products. During growth on ammonia nitrite accumulates, as a consequence, N. europaea cannot grow to high cell concentrations under conventional batch conditions. Here, we show that single-vessel dialysis membrane bioreactors can be used to obtain substantially increased N. europaea biomasses and substantially reduced nitrite levels in media initially containing high amounts of the substrate. Dialysis membrane bioreactor fermentations were run in batch as well as in continuous mode. Growth was monitored with cell concentration determinations, by assessing dry cell mass and by monitoring ammonium consumption as well as nitrite formation. In addition, metabolic activity was probed with in vivo acridine orange staining. Under continuous substrate feed, the maximal cell concentration (2.79???1012/L) and maximal dry cell mass (0.895 g/L) achieved more than doubled the highest values reported for N. europaea cultivations to date.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Folia Microbiologica. - 99 : 19 (2016), p. 7937-7944. -
További szerzők:	Török Tibor Karaffa Erzsébet Mónika (1972-) (mikrobiológus, egyetemi tanár) Fekete Erzsébet (1975-) (biotechnológus, egyetemi tanár) Flipphi, Michel (1964-) Karaffa Levente (1971-) (biotechnológus, egyetemi tanár)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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