scholarly journals Kinetic study and modeling of xylitol production using Candida tropicalis in different culture media using unstructured models

Author(s):  
Katherine Manjarres-Pinzón ◽  
Leonardo Barrios Ziolo ◽  
Mario E. Arias Zabala ◽  
Guillermo Correa Londoño ◽  
Eduardo Rodriguez Sandoval

Unstructured models for cell growth, xylose consumption and xylitol production were applied for to describe the fermentation kinetics of xylitol production using Candida tropicalis in synthetic medium,and in non-detoxified oil palm empty fruit bunch (OPEFB) hydrolysate at 100 mL flask scale. In synthetic medium, the experimental maximum specific growth rate (μmax) and the cell mass yield factor(YX/S) were closer to the results of the Tessier model than those of the Contois and Monod models. Whereas, in non-detoxified OPEFB hydrolyzate, these parameters were closer to the results of the Contois model than those of the Tessier and Monod models. According to the models’ results, xylitol is mainly produced during the cell growth phase. The Tessier model in synthetic medium and Contois model in non-detoxified OPEFB hydrolysate had a coefficient of variation in growth kinetics of 32 and 33%, respectively. The significance of this study lies in simplifying the fermentation process through an unstructured and non-segregated model using three events at the same time, cell growth, substrate consumption and metabolite production.

Tuberculosis (TB) is one of the most important zoonotic bacterial diseases. A huge economic loss which could be direct or indirect are associated with the disease. Currently, the primary methods used for detection of TB in humans and cattle include the measurement of a delayed type hypersensitivity to purified protein derivative (PPD). So, the need for preparation of purified PPD with adequate properties and increasing the final PPD yield with decreasing the time of tuberculin production has stimulated the interest in the development of its preparation. Our study was performed to compare between the standard and modified media for improving tuberculin production. Middle brook 7H10 agar medium was used as a modified basic medium for mycobacterial growth, followed by cultivation of mycobacteria on Middle brook 7H9 broth medium. For the production, strains were inoculated onto the culture medium (Dorest Henly synthetic medium). Other steps for tuberculin production was done according to standard Weighbridge protocol. The results demonstrated that the using of both Middle brook 7H10 agar and Middle brook 7H9 broth instead of Lowenstein-Jensen (LJ) and glycerin broth media which used in currently produced tuberculin, have better physical and chemical properties. In addition, reducing the time required for production by accelerating the time of microbial growth. Also, it was found that the tuberculin produced using modified media was slightly more potent or the same as currently tuberculin produced. So, both Middle brook 7H10 agar and Middle brook 7H9 broth media are recommended for production of tuberculin saving time and increasing potency of the product but more investigation was recommended for estimation types of protein present in both locally prepared and modified tuberculin.


2004 ◽  
Vol 26 (8) ◽  
pp. 623-627 ◽  
Author(s):  
Teak-Bum Kim ◽  
Yong-Joo Lee ◽  
Pil Kim ◽  
Chang Sup Kim ◽  
Deok-Kun Oh

Author(s):  
Gurusamy Muneeswaran ◽  
Sanjay K. S. Patel ◽  
Sanath Kondaveeti ◽  
Ramasamy Shanmugam ◽  
Krishnasamy Gopinath ◽  
...  

2000 ◽  
Vol 55 (3-4) ◽  
pp. 213-217 ◽  
Author(s):  
Walter de Carvalho ◽  
Silvio Silvério da Silva ◽  
Michele Vitolo ◽  
Ismael Maciel de Mancilha

Abstract In this study we used the yeast Candida guilliermondii FTI 20037 immobilized by entrapment in Ca-alginate beads (2 .5 -3 mm diameter) for xylitol production from concentrated sugarcane bagasse hemicellulosic hydrolysate in a repeated batch system. The fermentation runs were carried out in 125- and 250-ml Erlenmeyer flasks placed in an orbital shaker at 30 °C and 200 rpm during 72 h, keeping constant the proportion between work volume and flask total volume. According to the results, cell viability was substantially high (98%) in all fermentative cycles. The values of parameters xylitol yield and volumetric productivity increased significantly with the reutilization of the immobilized biocatalysts. The highest values of xylitol final concentration (11.05 g/1), yield factor (0.47 gig) and volumetric productivity (0.22 g/lh) were obtained in 250-ml Erlenmeyer flasks containing 80 ml of medium plus 20 mi of immobilized biocatalysts. The support used in this study (Ca-alginate) presented stability in the experimental conditions used. The results show that the use of immobilized cells is a promising approach for increasing the xylitol production rates.


2018 ◽  
Vol 19 (11) ◽  
pp. 3538 ◽  
Author(s):  
Brandon Lehrich ◽  
Yaxuan Liang ◽  
Pooya Khosravi ◽  
Howard Federoff ◽  
Massimo Fiandaca

It is known that culture media (CM) promotes cellular growth, adhesion, and protects explanted primary brain cells from in vitro stresses. The fetal bovine serum (FBS) supplement used in most CM, however, contains significant quantities of extracellular vesicles (EVs) that confound quantitative and qualitative analyses from the EVs produced by the cultured cells. We quantitatively tested the ability of common FBS EV-depletion protocols to remove exogenous EVs from FBS-supplemented CM and evaluated the influence such methods have on primary astrocyte culture growth and viability. We assessed two methodologies utilized for FBS EV removal prior to adding to CM: (1) an 18-h ultracentrifugation (UC); and (2) a commercial EV-depleted FBS (Exo-FBS™). Our analysis demonstrated that Exo-FBS™ CM provided the largest depletion (75%) of total FBS EVs, while still providing 6.92 × 109 ± 1.39 × 108 EVs/mL. In addition, both UC and Exo-FBS™ CM resulted in poor primary astrocyte cell growth and viability in culture. The two common FBS EV-depletion methods investigated, therefore, not only contaminate in vitro primary cell-derived EV analyses, but also provide a suboptimal environment for primary astrocyte cell growth and viability. It appears likely that future CM optimization, using a serum-free alternative, might be required to advance analyses of cell-specific EVs isolated in vitro.


2011 ◽  
Vol 101 (2) ◽  
pp. 393-402 ◽  
Author(s):  
Swati Misra ◽  
Shailendra Raghuwanshi ◽  
Pritesh Gupta ◽  
Kakoli Dutt ◽  
R. K. Saxena

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