Two-reactor, continuous culture fermentation for fuel ethanol production from lignocellulosic acid hydrolysate using Zymomonas mobilis and Scheffersomyces stipitis

RSC Advances ◽  
2014 ◽  
Vol 4 (69) ◽  
pp. 36412-36418 ◽  
Author(s):  
Gaurav Chaudhary ◽  
Sanjoy Ghosh
Keyword(s):  
Ethanol Production ◽  
Continuous Culture ◽  
Zymomonas Mobilis ◽  
Fuel Ethanol ◽  
Ethanol Productivity ◽  
Scheffersomyces Stipitis ◽  
Acid Hydrolysate

Multistage ethanol production from lignocellulosic acid hydrolysate using two different microorganisms in two reactors enhances the utilization of all sugars (pentose and hexose), with higher ethanol productivity.

Ethanol production from fructose in continuous culture by free and flocculent cells of Zymomonas mobilis

1984 ◽  
Vol 6 (6) ◽  
pp. 389-394 ◽  
Author(s):  
I. Toran-Diaz ◽  
V. K. Jain ◽  
J. C. Baratti
Keyword(s):  
Ethanol Production ◽  
Continuous Culture ◽  
Zymomonas Mobilis

scholarly journals Development of High-Productivity Continuous Ethanol Production using PVA-Immobilized Zymomonas mobilis in an Immobilized-Cells Fermenter

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Nurhayati Nurhayati ◽  
Chieh-Lun Cheng ◽  
Jo-Shu Chang
Keyword(s):  
Ethanol Production ◽  
Dilution Rate ◽  
Ethanol Fermentation ◽  
Zymomonas Mobilis ◽  
Immobilized Cells ◽  
Ethanol Productivity ◽  
Glucose Loading ◽  
Continuous Ethanol Fermentation ◽  
Residual Glucose ◽  
High Ethanol

Ethanol as one of renewable energy was being considered an excellent alternative clean-burning fuel to replace gasoline. Continuous ethanol fermentation systems had offered important economic advantages compared to traditional systems. Fermentation rates were significantly improved, especially when continuous fermentation was integrated with cell immobilization techniques to enrich the cells concentration in fermentor. Growing cells of Zymomonas mobilis immobilized in polyvinyl alcohol (PVA) gel beads were employed in an immobilized-cells fermentor for continuous ethanol fermentation from glucose. The glucose loading, dilution rate, and cells loading were varied in order to determine which best condition employed in obtaining both high ethanol production and low residual glucose with high dilution rate. In this study, 20 g/L, 100 g/L, 125 g/L and 150 g/L of glucose concentration and 20% (w/v), 40% (w/v) and 50% (w/v) of cells loading were employed with range of dilution rate at 0.25 to 1 h-1. The most stable production was obtained for 25 days by employing 100 g/L of glucose loading. Meanwhile, the results also exhibited that 125 g/L of glucose loading as well as 40% (w/v) of cells loading yielded high ethanol concentration, high ethanol productivity, and acceptable residual glucose at 62.97 g/L, 15.74 g/L/h and 0.16 g/L, respectively. Furthermore, the dilution rate of 4 hour with 100 g/L and 40% (w/v) of glucose and cells loading was considered as the optimum condition with ethanol production, ethanol productivity and residual glucose obtained were 49.89 g/L, 12.47 g/L/h, and 2.04 g/L, respectively. This recent study investigated ethanol inhibition as well. The present research had proved that high sugar concentration was successfully converted to ethanol. These achieved results were promising for further study.

scholarly journals Cellulosic Ethanol Production by Engineered Consortia of Scheffersomyces Stipitis and Zymomonas Mobilis

2021 ◽  
Author(s):  
Lingling Sun ◽  
Bo Wu ◽  
Zengqin Zhang ◽  
Jing Yan ◽  
Panting Liu ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Zymomonas Mobilis ◽  
Carbon Dioxide Emission ◽  
Superior Performance ◽  
Lignocellulosic Ethanol ◽  
Scheffersomyces Stipitis ◽  
Xylose Consumption ◽  
Metabolic Genes ◽  
Fermentation Strategy ◽  
Cost Efficient

Abstract Background: As one of the clean and sustainable energies, lignocellulosic ethanol has achieved much attention around the world. The production of lignocellulosic ethanol does not compete with people for food, while the consumption of ethanol could contribute to the carbon dioxide emission reduction. Two of the conditions that are needed to attain cost-efficient lignocellulosic ethanol production at an industrial scale are the simultaneous transformation of glucose and xylose to ethanol and a highly efficient ethanol fermentation process. Results: In this study, the consortia consisting of suspended Scheffersomyces stipitis CICC1960 and Zymomonas mobilis 8b were cultivated to successfully depress carbon catabolite repression (CCR) in 80G40XRM. With this strategy, a 5.52% more xylose consumption and a 6.52% higher ethanol titer were achieved by the consortium, in which the inoculation ratio between S. stipitis and Z. mobilis was 1:3, at the end of fermentation compared with the Z. mobilis 8b mono-fermentation. Subsequently, one copy of the xylose metabolic genes was inserted into the Z. mobilis 8b genome to construct Z. mobilis FR2, leading to the xylose final-consumption amount and ethanol titer improvement by 15.36% and 6.81%, respectively. Finally, various concentrations of corn stover hydrolysates, in which the sum of glucose and xylose concentrations in the hydrolysates were 60, 90, and 120 g/L respectively, were used to evaluate the fermentation performance of the consortium consisting of S. stipitis CICC1960 and Z. mobilis FR2. Fermentation results showed that a 1.56% - 4.59% higher ethanol titer was achieved by the consortium compared with the Z. mobilis FR2 mono-fermentation, and a 46.12% - 102.14% higher ethanol titer was observed in the consortium fermentation when compared with the S. stipitis CICC1960 mono-fermentation. Conclusions: The fermentation strategy used in this study, i.e., using a genetically modified consortium, had a superior performance in ethanol production, as compared with the S. stipitis CICC1960 mono-fermentation and the Z. mobilis FR2 mono-fermentation alone. Thus, this strategy has potential for future lignocellulosic ethanol production.

scholarly journals Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lingling Sun ◽  
Bo Wu ◽  
Zengqin Zhang ◽  
Jing Yan ◽  
Panting Liu ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Zymomonas Mobilis ◽  
Carbon Dioxide Emission ◽  
Strain Improvement ◽  
Superior Performance ◽  
Pcr Analysis ◽  
Lignocellulosic Ethanol ◽  
Fermentation Performance ◽  
Scheffersomyces Stipitis ◽  
Xylose Consumption

Abstract Background As one of the clean and sustainable energies, lignocellulosic ethanol has achieved much attention around the world. The production of lignocellulosic ethanol does not compete with people for food, while the consumption of ethanol could contribute to the carbon dioxide emission reduction. However, the simultaneous transformation of glucose and xylose to ethanol is one of the key technologies for attaining cost-efficient lignocellulosic ethanol production at an industrial scale. Genetic modification of strains and constructing consortia were two approaches to resolve this issue. Compared with strain improvement, the synergistic interaction of consortia in metabolic pathways should be more useful than using each one separately. Results In this study, the consortia consisting of suspended Scheffersomyces stipitis CICC1960 and Zymomonas mobilis 8b were cultivated to successfully depress carbon catabolite repression (CCR) in artificially simulated 80G40XRM. With this strategy, a 5.52% more xylose consumption and a 6.52% higher ethanol titer were achieved by the consortium, in which the inoculation ratio between S. stipitis and Z. mobilis was 1:3, compared with the Z. mobilis 8b mono-fermentation. Subsequently, one copy of the xylose metabolic genes was inserted into the Z. mobilis 8b genome to construct Z. mobilis FR2, leading to the xylose final-consumption amount and ethanol titer improvement by 15.36% and 6.81%, respectively. Finally, various corn stover hydrolysates with different sugar concentrations (glucose and xylose 60, 90, 120 g/L), were used to evaluate the fermentation performance of the consortium consisting of S. stipitis CICC1960 and Z. mobilis FR2. Fermentation results showed that a 1.56–4.59% higher ethanol titer was achieved by the consortium compared with the Z. mobilis FR2 mono-fermentation, and a 46.12–102.14% higher ethanol titer was observed in the consortium fermentation when compared with the S. stipitis CICC1960 mono-fermentation. Furthermore, qRT-PCR analysis of xylose/glucose transporter and other genes responsible for CCR explained the reason why the initial ratio inoculation of 1:3 in artificially simulated 80G40XRM had the best fermentation performance in the consortium. Conclusions The fermentation strategy used in this study, i.e., using a genetically modified consortium, had a superior performance in ethanol production, as compared with the S. stipitis CICC1960 mono-fermentation and the Z. mobilis FR2 mono-fermentation alone. This result showed that this strategy has potential for future lignocellulosic ethanol production.

Fermentation of Groundnut Shell Enzymatic Hydrolysate for Fuel Ethanol Production by Free and Sorghum Stalks Immobilized Cells of Pichia stipitis NCIM 3498

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Chandrasekhar Gajula ◽  
Anuj Kumar Chandel ◽  
Radhika Konakalla ◽  
Ravinder Rudravaram ◽  
Ravindra Pogaku ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Immobilized Cells ◽  
Pichia Stipitis ◽  
Fuel Ethanol ◽  
Enzymatic Hydrolysate ◽  
Groundnut Shell

scholarly journals The Quorum Sensing Auto-Inducer 2 (AI-2) Stimulates Nitrogen Fixation and Favors Ethanol Production over Biomass Accumulation in Zymomonas mobilis

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 ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Quorum Sensing ◽  
Ethanol Production ◽  
N2 Fixation ◽  
Energy Demand ◽  
Zymomonas Mobilis ◽  
Biomass Accumulation ◽  
High Energy ◽  
Gram Negative ◽  
Expression Of Genes

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.

scholarly journals Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 173
Author(s):  
Elena Domínguez ◽  
Pablo G. del Río ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
Lucília Domingues
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Xylose Reductase ◽  
Energy Crop ◽  
Scheffersomyces Stipitis ◽  
Fractionation Process ◽  
Renewable Source ◽  
Fast Growing ◽  
Engineered Strain

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.

Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium

2012 ◽  
Vol 160 (3-4) ◽  
pp. 229-235 ◽  
Author(s):  
Yu Shen ◽  
Jin-Song Guo ◽  
You-Peng Chen ◽  
Hai-Dong Zhang ◽  
Xu-Xu Zheng ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Nitrogen Source ◽  
Sweet Potato ◽  
Low Cost ◽  
Fuel Ethanol ◽  
High Gravity

scholarly journals Ethanol Production from Glucose and Xylose by Immobilized Zymomonas mobilis CP4(pZB5)

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
Keyword(s):  
Ethanol Production ◽  
Zymomonas Mobilis
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