The influence of the initial concentrations of glucose and yeast extract on the ethanolic fermentation by Pachysolen tannophilus

1990 ◽  
Vol 55 (3) ◽  
pp. 854-866 ◽  
Author(s):  
Rodríguez V. Bravo ◽  
Rubio F. Camacho ◽  
Villasclaras S. Sánchez ◽  
Vico M. Castro

The ethanolic fermentation in batch cultures of Pachysolen tannophilus was studied experimentally varying the initial concentrations of two of the components in the culture medium: glucose between 0 and 200 g l-1 and yeast extract between 0 and 8 g l-1. The yeast extract appears to be a significant component both in cell growth and for ethanol production.

2020 ◽  
Author(s):  
Runxia Li ◽  
Mingjie Jin ◽  
Jun Du ◽  
Shouwen Chen ◽  
Shihui Yang

Abstract Background: Microbial growth needs C, N, P, S as well as metal ions such as magnesium, which is a major cofactor for enzymes involved in various metabolic activities. Yeast extract is widely used as nitrogen supply as well as vitamins and growth factors to sustain microbial growth in the culture medium. Zymomonas mobilis is a model ethanologenic bacterium for ethanol production, and has been developing as a chassis for diverse biochemical production. Although yeast extract is routinely used to prepare rich medium (RM) for Z. mobilis, the glucose consumption and ethanol production of Z. mobilis in RM were not coupled with cell growth in some studies. Results: In this study, the effects of different nitrogen sources as well as the supplementation of additional nitrogen source into RM and minimum medium (MM) on cell growth and ethanol fermentation of Z. mobilis were investigated to understand the uncoupled cell growth and ethanol fermentation for efficient carbon utilization and optimal ethanol productivity of Z. mobilis. Our results indicated that nitrogen sources such as yeast extract from different companies affected cell growth, glucose utilization, and the corresponding ethanol production. We also quantified the concentrations of major ion elements in different organic nitrogen sources using the quantitative analytic approach of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), and demonstrated that metal ions such as magnesium in the media affected glucose consumption, cell growth, and ethanol fermentation. The effect of magnesium on gene expression was further investigated using RNA-Seq transcriptomics, and our result indicated that the lack of Mg2+ triggered stress responses while decreasing energy-consuming metabolism. Conclusions: Our work demonstrated that concentrations of metal ions such as magnesium and molybdenum in nitrogen sources are essential for vigorous cell growth, and the difference of Mg2+concentration in different yeast extract was one of the major factors affecting the coupling of cell growth and ethanol fermentation in Z. mobilis. We also revealed that genes responsive for Mg2+ deficiency in the medium were majorly related to stress responses and energy conservation. The importance of metal ions on cell growth and ethanol fermentation suggested that metal ions should become one of the parameters for monitoring the quality of commercial nitrogen sources and optimizing microbial culture medium for economic biochemical production.


1989 ◽  
Vol 54 (5) ◽  
pp. 1244-1256 ◽  
Author(s):  
F. Camacho Rubio ◽  
V. Bravo Rodríguez ◽  
S. Sánchez Villasclaras ◽  
M. Castro Vico

The ethanolic fermentation of 25 g l-1 solutions of glucose in batch cultures of Pachysolen tannophilus has been studied experimentally in terms of three environmental variables: initial pH from 1.5 to 6.5, temperatures of 25 °C, 30 °C and 35 °C and aeration values of Q = 0.150 v/v/min, Q = 0.075 v/v/min and Q = 0 v/v/min (i.e. with air entering through the stirring vortex alone). Using the values for the concentrations of biomass, residual glucose and ethanol produced at intervals throughout the experiments, the maximum specific rates of growth, glucose consumption and ethanol production, together with the biomass and ethanol yields, have been calculated. The most favourable conditions for ethanol production are an initial pH of about 3, temperature of 30 °C and Q = 0 v/v/min. Under these conditions the ethanol yield is approximately 0.36 (g ethanol) (g glucose)-1 and the maximum specific production rate is 1.2 (g ethanol) (g biomass)-1 h-1.


Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 59 ◽  
Author(s):  
Carolina Benevenuti ◽  
Alanna Botelho ◽  
Roberta Ribeiro ◽  
Marcelle Branco ◽  
Adejanildo Pereira ◽  
...  

Fermentation of gases from biomass gasification, named syngas, is an important alternative process to obtain biofuels. Sequential experimental designs were used to increase cell growth and ethanol production during syngas fermentation by Clostridium carboxidivorans. Based on ATCC (American Type Culture Collection) 2713 medium composition, it was possible to propose a best medium composition for cell growth, herein called TYA (Tryptone-Yeast extract-Arginine) medium and another one for ethanol production herein called TPYGarg (Tryptone-Peptone-Yeast extract-Glucose-Arginine) medium. In comparison to ATCC® 2713 medium, TYA increased cell growth by 77%, reducing 47% in cost and TPYGarg increased ethanol production more than four-times, and the cost was reduced by 31%. In 72 h of syngas fermentation in TPYGarg medium, 1.75-g/L of cells, 2.28 g/L of ethanol, and 0.74 g/L of butanol were achieved, increasing productivity for syngas fermentation.


1995 ◽  
Vol 79 (6) ◽  
pp. 566-571 ◽  
Author(s):  
Vicente Bravo ◽  
Fernando Camacho ◽  
Sebastián Sánchez ◽  
Eulogio Castro

1989 ◽  
Vol 11 (6) ◽  
pp. 443-448 ◽  
Author(s):  
Fatiou Toukourou ◽  
Luiz Donaduzzi ◽  
Andr� Miclo ◽  
Pierre Germain

2010 ◽  
pp. 819-822 ◽  
Author(s):  
Kristina Martinelle ◽  
Annika Mattsson ◽  
Brita Rippner-Blomqvist ◽  
Elisabeth Lindner

2001 ◽  
Vol 67 (8) ◽  
pp. 3650-3654 ◽  
Author(s):  
Chan B. Park ◽  
Sun Bok Lee ◽  
Dewey D. Y. Ryu

ABSTRACT Identification of physiological and environmental factors that limit efficient growth of hyperthermophiles is important for practical application of these organisms to the production of useful enzymes or metabolites. During fed-batch cultivation of Sulfolobus solfataricus in medium containing l-glutamate, we observed formation of l-pyroglutamic acid (PGA). PGA formed spontaneously from l-glutamate under culture conditions (78°C and pH 3.0), and the PGA formation rate was much higher at an acidic or alkaline pH than at neutral pH. It was also found that PGA is a potent inhibitor of S. solfataricus growth. The cell growth rate was reduced by one-half by the presence of 5.1 mM PGA, and no growth was observed in the presence of 15.5 mM PGA. On the other hand, the inhibitory effect of PGA on cell growth was alleviated by addition of l-glutamate or l-aspartate to the medium. PGA was also produced from the l-glutamate in yeast extract; the PGA content increased to 8.5% (wt/wt) after 80 h of incubation of a yeast extract solution at 78°C and pH 3.0. In medium supplemented with yeast extract, cell growth was optimal in the presence of 3.0 g of yeast extract per liter, and higher yeast extract concentrations resulted in reduced cell yields. The extents of cell growth inhibition at yeast extract concentrations above the optimal concentration were correlated with the PGA concentration in the culture broth. Although other structural analogues ofl-glutamate, such as l-methionine sulfoxide, glutaric acid, succinic acid, and l-glutamic acid γ-methyl ester, also inhibited the growth of S. solfataricus, the greatest cell growth inhibition was observed with PGA. We also observed that unlike other glutamate analogues,N-acetyl-l-glutamate enhanced the growth of S. solfataricus. This compound was stable under cell culture conditions, and replacement of l-glutamate with N-acetyl-l-glutamate in the medium resulted in increased cell density.


2012 ◽  
Vol 84 (2) ◽  
pp. 443-454 ◽  
Author(s):  
Diego S. Nascimento ◽  
Gildomar Valasques Junior ◽  
Pedro Fernandes ◽  
Geise C.A. Ribeiro ◽  
Danyo M. Lima ◽  
...  

Inulinase (β-2,1-D- fructan fructanohydrolase), EC 3.2.1.7, targets the β-2,1 linkage of inulin, a polyfructan consisting of linear β-2,1 linked fructose, and hydrolyzes it into fructose. This use provides an alternative to produce fructose syrup through the hydrolysis of inulin. The objective of this work was to study the production, characterization and applications of inulinases from the fungal endophyte CCMB 328 isolated from the Brazilian semi-arid region. Response Surface Methodology (RSM) was employed to evaluate the effect of variables (concentration of glucose and yeast extract), on secreted inulinase activities detected in the culture medium and also in the inulin hydrolysis. The results showed that the best conditions for inulinase production by CCMB 328 are 9.89 g / L for glucose and 1.09 g / L for yeast extract. The concentration of 0.20 mol/L of NaCl and KCl increased the activity of inulinase from CCMB 328 by approximately 63% and 37%, respectively. The results also showed that the inulinase has potential for inulin hydrolysis, whose conversion yields roughly 72.48 % for an initial concentration of inulin at 1% (w/v).


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