scholarly journals Enriching and characterizing an aerotolerant mixed microbial community capable of cellulose hydrolysis and ethanol production

2021 ◽  
Author(s):  
Patrick Ronan
Keyword(s):  
Yeast Extract ◽  
Fossil Fuels ◽  
Consolidated Bioprocessing ◽  
Cellulose Hydrolysis ◽  
Reducing Agent ◽  
Community Members ◽  
Fermentation Products ◽  
Nutrient Sources ◽  
Mixed Microbial Community ◽  
Aerobic And Anaerobic

Cellulosic ethanol produced via consolidated bioprocessing may one day be a viable alternative to fossil fuels However, efforts must focus on streamlining and simplifying its production in order to make this a reality. The aim of this study was to enrich a cellulolytic community and characterize its soluble end-products and bacterial diversity. The community degraded cellulose in the absence of reducing agent, and appeared to generate anaerobic conditions through oxygen-consuming aerobic respiration. Ethanol and acetate were the major fermentation products and the activity of the community was stable in aerobic and anaerobic media, as well as yeast extract-free aerobic media supplemented with other waste-based nutrient sources. Several community members showed high similarity to Clostridium species, suggesting the presence of some functional redundancy. Reducing agent and yeast extract both represent significant costs in the culturing of cellulolytic, ethanologenic microorganisms. The community described here exhibited this activity in the absence of both.

scholarly journals Enriching and characterizing an aerotolerant mixed microbial community capable of cellulose hydrolysis and ethanol production

2021 ◽  
Author(s):  
Patrick Ronan
Keyword(s):  
Yeast Extract ◽  
Fossil Fuels ◽  
Consolidated Bioprocessing ◽  
Cellulose Hydrolysis ◽  
Reducing Agent ◽  
Community Members ◽  
Fermentation Products ◽  
Nutrient Sources ◽  
Mixed Microbial Community ◽  
Aerobic And Anaerobic

Cellulosic ethanol produced via consolidated bioprocessing may one day be a viable alternative to fossil fuels However, efforts must focus on streamlining and simplifying its production in order to make this a reality. The aim of this study was to enrich a cellulolytic community and characterize its soluble end-products and bacterial diversity. The community degraded cellulose in the absence of reducing agent, and appeared to generate anaerobic conditions through oxygen-consuming aerobic respiration. Ethanol and acetate were the major fermentation products and the activity of the community was stable in aerobic and anaerobic media, as well as yeast extract-free aerobic media supplemented with other waste-based nutrient sources. Several community members showed high similarity to Clostridium species, suggesting the presence of some functional redundancy. Reducing agent and yeast extract both represent significant costs in the culturing of cellulolytic, ethanologenic microorganisms. The community described here exhibited this activity in the absence of both.

NOx Reduction Review on Fuel Alternative in Cement Kiln

2013 ◽  
Vol 864-867 ◽  
pp. 1626-1629
Author(s):  
Hai Bing Liu ◽  
Xiao Dong Chen ◽  
Jun Gu
Keyword(s):  
Nitrogen Content ◽  
Fossil Fuels ◽  
Nox Reduction ◽  
Reducing Agent ◽  
Environmental Benefits ◽  
Nox Emission ◽  
Cement Kiln ◽  
Cement Kilns ◽  
Low Nitrogen

The paper first discusses the relativity between alternative combustion andNOx emissions by a test in dry cement kiln, and a lot of case on fuel alternative The main findings of the study are that the use of RDF in cement kilns instead of coal or coke offers environmental benefits and reduce NOx emission. The conclusion is that the NOx generation can probably be lower because of lower flame temperatures or lower air excess and low nitrogen content in comparison with fossil fuels also is impartment reason., another a fact that most of the nitrogen (N) in biomass is released as ammonia (NH3) which acts as a reducing agent with NOx to form nitrogen (N2).

scholarly journals Optimization of alcoholic fermentation using immobilized yeast cells in calcium alginate gel

2015 ◽  
pp. 207-218
Author(s):  
Jovana Djuran ◽  
Zorana Roncevic ◽  
Bojana Bajic ◽  
Sinisa Dodic ◽  
Jovana Grahovac ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Yeast Extract ◽  
Fossil Fuels ◽  
Alcoholic Fermentation ◽  
Immobilized Cells ◽  
Alginate Beads ◽  
Yeast Cells ◽  
Glucose Content ◽  
Alginate Concentration ◽  
Economic Analyses

Ethanol is an important industrial chemical with emerging potential as a biofuel to replace fossil fuels. In order to enhance the efficiency and yield of alcoholic fermentation, combined techniques such as cells immobilization and media optimization have been used. The aim of this study was the optimization of sodium alginate concentration and glucose and yeast extract content in the media for ethanol production with immobilized cells of Saccharomyces cerevisiae. Optimization of these parameters was attempted by using a Box-Behnken design using the response surface methodology. The obtained model predicts that the maximum ethanol content of 7.21% (v/v) is produced when the optimal values of sodium alginate concentration and initial content of glucose and yeast extract in the medium are 22.84 g/L, 196.42 g/L and 3.77 g/L, respectively. To minimize the number of yeast cells "eluted" from the alginate beads and residual glucose content in fermented media, additional two sets of optimization were made. The obtained results can be used for further techno-economic analyses of the process to select the optimum conditions of the fermentation process for industrial application.

Effect of culture media and pH on the biomass production and biocontrol efficacy of aMetschnikowia pulcherrimastrain to be used as a biofungicide for postharvest disease control

2010 ◽  
Vol 56 (2) ◽  
pp. 128-137 ◽  
Author(s):  
D. Spadaro ◽  
A. Ciavorella ◽  
Z. Dianpeng ◽  
A. Garibaldi ◽  
M. L. Gullino
Keyword(s):  
Biomass Production ◽  
Yeast Extract ◽  
Culture Media ◽  
Carbon Sources ◽  
Ph Control ◽  
Cell Number ◽  
Penicillium Expansum ◽  
Postharvest Disease ◽  
Yeast Growth ◽  
Nutrient Sources

Few strains of Metschnikowia pulcherrima (Pitt) M.W. Miller are under development for control of postharvest pathogens on fruit. A substrate was developed to optimize the biomass production of M. pulcherrima strain BIO126. Different complex nutrient sources, with or without pH control, were tested. Growth in yeast extract provided at concentrations ≥30 g·L–1yielded the highest biomass. The addition of two carbon sources, d-mannitol and l-sorbose, at 5 g·L–1each, significantly improved yeast growth. The greatest amount of yeast growth occurred when pH values of the medium ranged from 5.0 to 7.5. A combination of yeast extract, d-mannitol, and l-sorbose (YEMS), probably with diauxic utilization, showed a synergistic effect, widening the exponential phase (maximum specific growth rate of 0.45 h–1) and increasing the final cell number (1.5 × 109cells·mL–1) and dry biomass (6.0 g·L–1) in well-controlled batch fermentation. In efficacy trials on ‘Golden Delicious’ apples, M. pulcherrima grown in YEMS effectively reduced incidence and severity of Botrytis cinerea (51.1% and 70.8%, respectively) and Penicillium expansum (41.7% and 14.0%, respectively). Also on ‘Gala’ apples, the best reduction of grey and blue mould incidence was obtained with cells grown in YEMS (58.1% and 50.5%, respectively).

Substitution of Biomass for Coal and Coke in Ironmaking Process

2011 ◽  
Vol 236-238 ◽  
pp. 77-82 ◽  
Author(s):  
Zheng Wen Hu ◽  
Jian Liang Zhang ◽  
Hai Bin Zuo ◽  
Mi Tian ◽  
Zheng Jian Liu ◽  
...  
Keyword(s):  
Energy Conservation ◽  
Solid Fuel ◽  
Emission Reduction ◽  
Fossil Fuels ◽  
Reducing Agent ◽  
Biomass Energy ◽  
Metallurgical Coal ◽  
Ironmaking Process ◽  
Effective Use ◽  
Application Prospects

Biomass is renewable and carbon neutral. Biochar, derived from the carbonization of biomass, is a kind of solid fuel with excellent properties. Utilization of biomass in ironmaking process as heating agent and reducing agent contributes to energy conservation and emission reduction, and can partially replace for coal and coke. Research status of the utilization of biomass in ironmaking process is discussed. Application prospects of biomass energy in ironmaking process are analyzed, and a novel bioenergy auxiliary ironmaking system is suggested, which is meaningful for the effective use of biomass and for decreasing the consumption of fossil fuels, namely metallurgical coal and coke.

Some Observations on a Perigo-Type Inhibition of Clostridium botulinum in a Simplified Medium

1975 ◽  
Vol 38 (12) ◽  
pp. 762-763 ◽  
Author(s):  
C. N. HUHTANEN
Keyword(s):  
Yeast Extract ◽  
Clostridium Botulinum ◽  
Type A ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Sensitive Assay ◽  
Vegetative Cells ◽  
Botulinum Type ◽  
Better Than

A rapid and sensitive assay for Perigo factor was developed using a medium of 0.5% yeast extract and tryptone, 0.2% glucose, 0.12% K2HPO4 and 0.1% cysteine HCI or sodium thioglycollate and vegetative cells of Clostridium botulinum type A. Yeast extract or tryptone, together with a reducing agent (cysteine, sodium thioglycollate, or glucose autoclaved with the medium), produced a Perigo inhibitor when autoclaved at 15 psi for 15 min with NaNO2. Tryptone was more active than yeast extract as a source of the Perigo inhibitor; of the reducing agents tested cysteine was more effective in producing Perigo-type inhibition than thioglycollate and either was better than glucose autoclaved with the medium.

Antibiotic activity of an isocyanide metabolite of Trichoderma hamatum against rumen bacteria

1985 ◽  
Vol 31 (9) ◽  
pp. 767-772 ◽  
Author(s):  
S. N. Liss ◽  
D. Brewer ◽  
A. Taylor ◽  
G. A. Jones
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Rumen Fluid ◽  
Cellulose Hydrolysis ◽  
Soluble Carbohydrate ◽  
Rumen Bacteria ◽  
Fermentation Products ◽  
Fluid Medium ◽  
Trichoderma Hamatum ◽  
Significant Depression

A metabolite of Trichoderma hamatum, 3-(3-isocyanocyclopent-2-enylidene)propionic acid, was tested for its effects on growth of and carbohydrate metabolism in 11 strains of functionally important rumen bacteria. To standardize the biological activity of this unstable metabolite, a rapid, aerobic disc diffusion assay was developed using Escherichia coli ATCC 11775. In an anaerobic broth dilution assay using a medium lacking rumen fluid and containing a soluble carbohydrate, the minimum inhibitory concentration of the metabolite which completely inhibited growth of the rumen bacteria for 18 h at 39 °C was generally < 10 μg∙mL−1; however, the minimum inhibitory concentrations for Megasphaera elsdenii B159 and Streptococcus bovis Pe18 were 10–25 and 25–64 μg∙mL−1, respectively. In general, the Gram-negative strains were more sensitive than the Gram positive. The minimum inhibitory concentration for Bacteroides ruminicola 23 grown with glucose was 1 μg∙mL−1; for B. ruminicola GA33 (glucose), B. succinogenes S85 (cellobiose), and Succinivibrio dextrinosolvens 24 (maltose), it was 2 μg∙mL−1. When added to a cellulose-containing rumen fluid medium, 1–4 μg∙mL−1 of the metabolite delayed cellulose hydrolysis by B. succinogenes S85, Ruminococcus albus 7, and R. flavefaciens FD1 for up to 4 days, and 6–7 μg∙mL−1 prevented hydrolysis for at least 1 month. In the presence of the metabolite, the proportion of acetate produced from soluble carbohydrate by the majority of strains increased, but with some strains net production of acetate decreased relative to production of other acidic fermentation products. If the metabolite gained entrance to the rumen, a concentration of as little as 1 μg∙mL−1 would probably cause a significant depression of the fermentation and result in nutritional deprivation of the animal.

scholarly journals Yeast Surface Display of Trifunctional Minicellulosomes for Simultaneous Saccharification and Fermentation of Cellulose to Ethanol

2009 ◽  
Vol 76 (4) ◽  
pp. 1251-1260 ◽  
Author(s):  
Fei Wen ◽  
Jie Sun ◽  
Huimin Zhao
Keyword(s):  
Cell Surface ◽  
Consolidated Bioprocessing ◽  
Surface Display ◽  
Cellulose Hydrolysis ◽  
Cellulase Production ◽  
Single Step ◽  
Yeast Surface Display ◽  
Biofuel Production ◽  
Yeast Cells ◽  
Recombinant Yeast Strain

ABSTRACT By combining cellulase production, cellulose hydrolysis, and sugar fermentation into a single step, consolidated bioprocessing (CBP) represents a promising technology for biofuel production. Here we report engineering of Saccharomyces cerevisiae strains displaying a series of uni-, bi-, and trifunctional minicellulosomes. These minicellulosomes consist of (i) a miniscaffoldin containing a cellulose-binding domain and three cohesin modules, which was tethered to the cell surface through the yeast a-agglutinin adhesion receptor, and (ii) up to three types of cellulases, an endoglucanase, a cellobiohydrolase, and a β-glucosidase, each bearing a C-terminal dockerin. Cell surface assembly of the minicellulosomes was dependent on expression of the miniscaffoldin, indicating that formation of the complex was dictated by the high-affinity interactions between cohesins and dockerins. Compared to the unifunctional and bifunctional minicellulosomes, the quaternary trifunctional complexes showed enhanced enzyme-enzyme synergy and enzyme proximity synergy. More importantly, surface display of the trifunctional minicellulosomes gave yeast cells the ability to simultaneously break down and ferment phosphoric acid-swollen cellulose to ethanol with a titer of ∼1.8 g/liter. To our knowledge, this is the first report of a recombinant yeast strain capable of producing cell-associated trifunctional minicellulosomes. The strain reported here represents a useful engineering platform for developing CBP-enabling microorganisms and elucidating principles of cellulosome construction and mode of action.

scholarly journals Microbial Cellulose Utilization: Fundamentals and Biotechnology

2002 ◽  
Vol 66 (3) ◽  
pp. 506-577 ◽  
Author(s):  
Lee R. Lynd ◽  
Paul J. Weimer ◽  
Willem H. van Zyl ◽  
Isak S. Pretorius
Keyword(s):  
Consolidated Bioprocessing ◽  
Quantitative Description ◽  
Product Yield ◽  
Cellulose Hydrolysis ◽  
Taxonomic Diversity ◽  
Cellulosic Biomass ◽  
Limiting Factors ◽  
Cellulolytic Enzymes ◽  
Cellulase Enzymes ◽  
Microbial Cellulose

SUMMARY Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for “consolidated bioprocessing” (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

scholarly journals Emerging Technologies for Waste to Energy Production: A General Review

2021 ◽  
Author(s):  
Kajal Saini ◽  
Keshav Saini
Keyword(s):  
Developing Countries ◽  
Organic Matter ◽  
Energy Production ◽  
Fossil Fuels ◽  
Landfill Gas ◽  
Waste To Energy ◽  
Huge Amount ◽  
Conversion Technologies ◽  
Aerobic And Anaerobic ◽  
Growing Population

Growing population leads to industrialisation and urbanization which in turn generate huge amount of waste that represents a big problem for many developed and developing countries. Emerging solution for this problem can be use of wastes as a sustainable source of energy in the form of heat, electricity, fertilizer and biofuel like bioethanol. Type of technology employed is mainly based on the composition of waste whether it is rich in organic matter like MSW or not. WTE technologies reduce the volume of waste as well as decrease the dependence on fossil fuels for energy generation.This study focuses on overview of various available waste to energy conversion technologies like pyrolysis, gasification, incineration, biochemical treatments like landfill gas, aerobic and anaerobic digestion of wastes.

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