Comparative study of ethanol production by immobilized-cell systems using Zymomonas mobilis or Saccharomyces bayanus

1982 ◽  
Vol 14 (2) ◽  
pp. 59-63 ◽  
Author(s):  
G. Amin ◽  
H. Verachtert
Author(s):  
Paulo Roberto Dall Cortivo ◽  
Luiza Fichtner Aydos ◽  
Lilian Raquel Hickert ◽  
Carlos Augusto Rosa ◽  
Ronald E. Hector ◽  
...  

2019 ◽  
Vol 12 (1) ◽  
pp. 199-210
Author(s):  
Thalisa Yuwa-Amornpitak ◽  
Pa-Nga Yeunyaw

In order to develop a procedure for production bioethanol from cassava pulp, mixed culture of Amylomyces rouxii TISTR 3667 with Zygosaccharomyces pseudorouxii TISTR 5966 or Zymomonas mobilis TISTR 550 and cellulase were evaluated. The parameters such as pH, cellulase, and cassava pulp concentration that influence on the amount of fermentable sugar were optimized by response surface methodology (RSM). Ethanol production was observed and compared to the predicted value that was calculated from the models. The models were fitted to a second-order polynomial equation. They were used to predict ethanol concentration from the use of the mixed culture of A. rouxii TISTR 3667 and Z. mobilis TISTR 550 (G2) that was higher than the amount produced using the mixed culture of A. rouxii TISTR 3667 and Zygosaccharomyces pseudorouxii TISTR 5966 (G1). The following optimum parameters were obtained: pH 6, 20% cassava pulp, and 1% cellulase for G2; and pH 4, 20% cassava pulp, and 0.55% cellulase for G1. The effect of cellulase on ethanol production, a comparative study was conducted in the fermenter by using mixed culture of A. rouxii TISTR 3667 and Z. mobilis TISTR 550. It was showed that more 15% ethanol was gained from 10% cassava pulp with 0.5% cellulase (25 g/l ethanol) compared to the system without cellulase (20 g/l). Mathematically model (equation 4) predicted the ethanol in this system near the actual value of 26.87 g/l. This study indicated that RSM is a powerful tool for optimization fermentation process by using mixed culture including cellulase. Besides these cellulase also reduced viscosity of the cassava medium and enhanced ethanol production. However this process should be more continue to study.


1983 ◽  
Vol 1 (4) ◽  
pp. 339-393 ◽  
Author(s):  
Argyrios Margaritis ◽  
Fahar J. A. Merchant ◽  
Bernard J. Abbott

2021 ◽  
Vol 22 (11) ◽  
pp. 5628
Author(s):  
Valquíria Campos Alencar ◽  
Juliana de Fátima dos Santos Silva ◽  
Renata Ozelami Vilas Boas ◽  
Vinícius Manganaro Farnézio ◽  
Yara N. L. F. de Maria ◽  
...  

Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants.


2000 ◽  
Vol 84-86 (1-9) ◽  
pp. 525-542 ◽  
Author(s):  
Mahesh S. Krishnan ◽  
Maria Blanco ◽  
Christopher K. Shattuck ◽  
Nhuan P. Nghiem ◽  
Brian H. Davison

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