Kinetic Parameters of the Carotenoids Production by Rhodotorula glutinis under Different Concentration of Carbon Source

Author(s):  
Ayerim Hernández-Almanza ◽  
Víctor Navarro-Macías ◽  
Oscar Aguilar ◽  
Juan C. Contreras-Esquivel ◽  
Julio C. Montañez ◽  
...  
2005 ◽  
Vol 60 (1-2) ◽  
pp. 116-120 ◽  
Author(s):  
Emiliya Pisareva ◽  
Valentin Savov ◽  
Anna Kujumdzieva

Citrinin is a mycotoxin, which is produced by fungi belonging to the genus Monascus, known in biotechnology as producers of azaphilone pigments. The relation between biosynthesis of these secondary metabolites was investigated in different species of the genus Monascus in batch-culture at the following cultivation conditions: T = 28 °C, agitation 220 rpm, and a medium, which induce citrinin production, containing ethanol as a carbon source. The screening was carried out with 16 fungal strains and the biosynthesis of citrinin and pigments was monitored quantitatively at the standard conditions mentioned above. Some kinetic parameters of the process have been determined. The values of the growth yield coefficient YX/C were between 0.32 and 0.57. The amount of the extracellular red and orange pigments at the end of cultivation varied for the different strains between 0.09 and 1.33 OU/ mg dry weight, and 0.15 and 0.96 OU/mg dry weight, respectively. The amount of the total pigments measured was between 0.16 and 3.6 OU/mg dry weight, and between 0.21 and 3.39 OU/mg dry weight. The determined ratio 500 nm/400 nm, characterizing the pigment production, ranged between 0.60 and 1.06. Twelve of the investigated strains produced citrinin and pigments, two of them produced only pigments. Two strains were not able to produce neither pigments nor citrinin. Thus, the biosynthesis of citrinin appeared to be strain-specific and does not correlate with the pigments’ biosynthesis by the fungal strains belonging to the genus Monascus.


1994 ◽  
Vol 30 (9) ◽  
pp. 59-66 ◽  
Author(s):  
Keiko Katayama-Hirayama ◽  
Shusaku Tobita ◽  
Kimiaki Hirayama

Biodegradation of phenol and monochlorophenols (CPs) by a yeast strain of Rhodotorula glutinis was examined. The strain completely degraded 5 mM of phenol and utilized phenol as a sole carbon source. The strain may degrade phenol by the “ortho” type of ring fission because muconolactone was observed in the cultured broth. 3-Chlorophenol (3-CP) and 4-chlorophenol (4-CP) were well degraded and stoichiometric release of chloride ion was observed, but degradation of 2-chlorophenol was low with a small quantity of chloride ions. Biodegradability of 3-CP and 4-CP was increased by the addition of phenol or CPs to the medium at the cell cultivation. Since 4-chlorocatechol and maleylacetic acid were determined as metabolites of 3-CP and 4-CP by GC/MS analysis, dechlorination may take place between the formation of 4-chlorocatechol and maleylacetic acid.


2017 ◽  
Vol 2 (2) ◽  
pp. 169-176
Author(s):  
Edna María Hernández-Domínguez ◽  
Carmen Sánchez ◽  
Gerardo Díaz-Godínez

In this study, activities of laccases, xylanases and cellulases produced by Pleurotus ostreatus in liquid-state fermentation were evaluated. Three fermentations were done by triplicate where the carbon source was changed, one was made with glucose, in another was used carboxymethylcellulose and xylan and in the third the three carbon sources were added, in all cases, copper was added as inducer of laccases. The kinetic parameters of growth of the fungus were obtained. It was observed that this fungus produced the three enzymes evaluated; laccases showed the highest values (34,240 U/L) in the culture medium with glucose as sole carbon source. Cellulases showed their highest activity in the culture medium with xylan and carboxymethylcellulose (12,858 U/L) and xylanases in medium with glucose, carboxymethyl cellulose and xylan (27,153 U/L). Up to 4 isoform of laccases, 2 of xylanase and 2 of cellulases were observed by zymography.


2013 ◽  
Vol 8 (1) ◽  
pp. 68-74

Kinetics for the biological processes of nitrification, denitrification and carbon oxidation were studied in the aerobic and anoxic phases of a pilot scale Biological Nutrient Removal (BNR) plant treating municipal wastewater. The configuration of the treating system is based on the combination of the UCT (University of Cape Town) design and the step feeding process in a cascade denitrification. In order to study the process kinetics and to obtain reliable values for the investigated kinetic parameters batch experiments were performed. For this purpose, continuous feeding of the treating system was interrupted for a given period of time and the pilot plant was turned into a batch mode of operation. Thereafter, addition of NO3 --N and NH4 +-N into the anoxic and aerobic compartments of the treating plant, respectively, followed, whereas adequate initial concentration of a carbon source (municipal wastewater or synthetic substrate) was ensured in the mixed liquor. Experimental data indicated that the examined biological processes followed saturation kinetics. The maximum specific denitrification rate, qDN,max , was found to obtain values, depending on the type of the carbon source, between 0,045 and 0,390 gNO3 --N/(gXHET·d), whereas the extremely low value of the half saturation constant for the denitrification process (Km,NO3-N << 1mgN/l) indicated its description by zero order kinetics. The maximum specific nitrification rate, qN,max, was determined to vary in a narrow frame, between 1,28 and 1,60 gNH4 +- N/(gXAO·d). The half saturation constant for the nitrification process, Km,NH4-N, was estimated graphically at 3,1 – 6,1 gNH4 +-N l-1, corresponding to 62 – 122 μgNH3-N l-1. These values are considered to be in good agreement with the literature. The determination of kinetic parameters can be considered as a useful tool for the process design, operation and improvement of wastewater treatment plants. Furthermore, the study of the biological process kinetics contributes to the better understanding and outline of the complicated biological processes that contemporarily take place within the various phases of BNR wastewater treatment plants.


Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


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