Forough Asgary Karchegany; Marzieh Shamee; Gholamreza Ghezelbash; Iraj Nahvi
Abstract
Xylitol is a naturally five – carbon polyol with a high sweetening power. Xylitol is the sweetest among the polyalcohols. The biotechnological method of producing xylitol by microorganisms has been studied as an alternative to the chemical method and is very environmentally safe. Xylitol is an ...
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Xylitol is a naturally five – carbon polyol with a high sweetening power. Xylitol is the sweetest among the polyalcohols. The biotechnological method of producing xylitol by microorganisms has been studied as an alternative to the chemical method and is very environmentally safe. Xylitol is an attractive sugar substitute for use in the food-processing, nutritional supplement and pharmaceutical industries. Among the microorganisms, yeasts are considered as the best xylitol producer. The purpose of this study was xylitol production by Debaryomyces hansenii that isolated from pollen of Malva sylvestris flower. This strain was identified by 18SrRNA sequencing and following its alignment with existed similar strains in data bases. Xylitol was produced in production medium contained xylose and other compounds. Xylitol was first identified by thin layer chromatography (TLC) method then it was confirmed by Megasyme kit. Xylitol concentration was quantified using high performance liquid chromatography ( HPLC) method. This strain produced 20.45 g l-1 xylitol after 48 hours culture incubation in medium contained 40 g l-1 xylose.
Marjan Enshaeieh; Mahboobeh Madani; Azadeh Abdoli; Iraj Nahvi; Forough Asgary Karchegany
Abstract
The application of microorganisms in the production of economically valuable products has attracted a great attention in recent years. These valuable materials such as single cell oil and poly-alcohols have potential for application in various industrial fields. Single cell oil in biodiesel production ...
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The application of microorganisms in the production of economically valuable products has attracted a great attention in recent years. These valuable materials such as single cell oil and poly-alcohols have potential for application in various industrial fields. Single cell oil in biodiesel production and poly-alcohols such as xylitol in the food and pharmaceutical industries, are valuable. In this study high production of SCO was evaluated and analyzing of SCO was done by FTIR spectroscopy. In addition, xylitol production by the yeast, in the media containing xylose was done and xylitol was analyzed by using colorimetric method. Optimization of microbial oil and xylitol production was done by Taguchi method and valuable results were obtained. This strain was reached to SCO production and dry biomass of 10.21 g/L in optimum condition including 100 g/L glucose, 72 h incubation time, pH = 5, temperature of 25 ºC and rpm=180. In addition, in the medium with 140 g/L of xylose, xylitol production was 54.99 g/L. The results of this study can show that there are native yeasts with high potential of producing valuable materials which can be directed to produce the desired products by providing appropriate medium condition.
Hossein Ghanavati; Iraj Nahvi
Abstract
In present study, oleaginous yeast Rhodotorula mucilaginosa strain UIMC35 was isolated and identified for SCO (single Cell Oil) production. Flow cytometric technique was employed for the monitoring of fluorescence intensity of the cells (channel FL2), cell size (by FSC parameter) and the cell granularity ...
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In present study, oleaginous yeast Rhodotorula mucilaginosa strain UIMC35 was isolated and identified for SCO (single Cell Oil) production. Flow cytometric technique was employed for the monitoring of fluorescence intensity of the cells (channel FL2), cell size (by FSC parameter) and the cell granularity (by SSC parameter). The relationship between fluorescence intensity and lipid content in order to quick and easy calculation of the amount of lipid content was presented. Changes in various factors such as lipid and biomass production, lipid content, lipid and biomass production efficiency, the amount of sugar, the amount of nitrogen, C/N ratio and pH were investigated at different stages of yeast strain batch culture. The highest rates of lipid production, lipid content and lipid production efficiency by this yeast strain were achieved 6.57 g/l, 67.04 % and 21.13 %, respectively. Decreasing of C/N ratio in the later stages of yeast growth caused the reduction of the lipid production rate.
Marahem Ashengarf; Eraj Nahvi; Jahanshir Amini
Abstract
In the recent years, the use of microbial biotransformation processes to achieve specific properties of vanillin and access to the natural vanillin origin has been a lot of attention. In the present study, Taguchi method was employed for optimizing the biotransformation of isoeugenol to vanillin under ...
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In the recent years, the use of microbial biotransformation processes to achieve specific properties of vanillin and access to the natural vanillin origin has been a lot of attention. In the present study, Taguchi method was employed for optimizing the biotransformation of isoeugenol to vanillin under resting cells of native isolate Psychrobacter sp. strain CSW4. Five factors, i.e. initial isoeugenol concentration, initial dry biomass, co-substrates (glycerol, yeast extract and tryptone), initial NaCl concentration and metal ions (Cu, Zn and Co, were selected and experiments based on an orthogonal array layout of L18 were performed. Vanillin produced in the biotransformation reaction mixture was analyzed by HPLC method. Optimization of the process by Taguchi method showed that highest impact factors with importance priority of NaCl concentration, initial isoeugenol concentration, glycerol as substrate, cobalt ion and initial dry biomass were determined as optimum conditions for the biotransformation isoeugenol into vanillin, respectively. Under these optimized conditions, the highest vanillin concentration (1.016 g/L) obtained after 24-h reaction biotransformation. The molar yield of vanillin produced from isoeugenol was 43.8 %. Results of this study indicate that if optimization of medium composition is performed to balance the cell growth and vanillin amount, reasonable yields of vanillin have been achieved, without addition of any toxic organic solvent or other chemicals which increase the cost of production.
