scholarly journals Seaweed Bioethanol Production: A Process Selection Review on Hydrolysis and Fermentation

Fermentation ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 99 ◽  
Author(s):  
Felix Offei ◽  
Moses Mensah ◽  
Anders Thygesen ◽  
Francis Kemausuor
Keyword(s):  
Fossil Fuels ◽  
Ethanol Yield ◽  
Process Efficiency ◽  
Bioethanol Production ◽  
Substrate Selection ◽  
Process Selection ◽  
Enzyme Preparations ◽  
Red Seaweeds ◽  
Composition And Structure ◽  
Polysaccharide Composition

The rapid depletion and environmental concerns associated with the use of fossil fuels has led to extensive development of biofuels such as bioethanol from seaweeds. The long-term prospect of seaweed bioethanol production however, depends on the selection of processes in the hydrolysis and fermentation stages due to their limiting effect on ethanol yield. This review explored the factors influencing the hydrolysis and fermentation stages of seaweed bioethanol production with emphasis on process efficiency and sustainable application. Seaweed carbohydrate contents which are most critical for ethanol production substrate selection were 52 ± 6%, 55 ± 12% and 57 ± 13% for green, brown and red seaweeds, respectively. Inhibitor formation and polysaccharide selectivity were found to be the major bottlenecks influencing the efficiency of dilute acid and enzymatic hydrolysis, respectively. Current enzyme preparations used, were developed for starch-based and lignocellulosic biomass but not seaweeds, which differs in polysaccharide composition and structure. Also, the identification of fermenting organisms capable of converting the heterogeneous monomeric sugars in seaweeds is the major factor limiting ethanol yield during the fermentation stage and not the SHF or SSF pathway selection. This has resulted in variations in bioethanol yields, ranging from 0.04 g/g DM to 0.43 g/g DM.

scholarly journals CELLULOSIC BIOETHANOL PRODUCTION FROM ULVA LACTUCA MACROALGAE

2021 ◽  
Vol 55 (5-6) ◽  
pp. 629-635
Author(s):  
AMINA ALLOUACHE ◽  
AZIZA MAJDA ◽  
AHMED ZAID TOUDERT ◽  
ABDELTIF AMRANE ◽  
MERCEDES BALLESTEROS
Keyword(s):  
Enzymatic Hydrolysis ◽  
Fossil Fuels ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Arable Land ◽  
Ulva Lactuca ◽  
Marine Macroalgae ◽  
Bioethanol Production ◽  
Acid Pretreatment ◽  
Total Glucose

Nowadays, the use of biofuels has become an unavoidable solution to the depletion of fossil fuels and global warming. The controversy over the use of food crops for the production of the first-generation biofuels and deforestation caused by the second-generation ones has forced the transition to the third generation of biofuels, which avoids the use of arable land and edible products, and does not threaten biodiversity. This generation is based on the marine and freshwater biomass, which has the advantages of being abundant or even invasive, easy to cultivate and having a good energetic potential. Bioethanol production from Ulva lactuca, a local marine macroalgae collected from the west coast of Algiers, was examined in this study. Ulva lactuca showed a good energetic potential due to its carbohydrate-rich content: 9.57% of cellulose, 6.9% of hemicellulose and low lignin content of 5.11%. Ethanol was produced following the separate hydrolysis and fermentation process (SHF), preceded by a thermal acid pretreatment at 120 °C during 15 min. Enzymatic hydrolysis was performed using a commercial cellulase (Celluclast 1.5 L), which saccharified the cellulose contained in the green seaweed, releasing about 85.01% of the total glucose, corresponding to 7.21 g/L after 96 h of enzymatic hydrolysis at pH 5 and 45 °C. About 3.52 g/L of ethanol was produced after 48 h of fermentation using Saccharomyces cerevisiae at 30 °C and pH 5, leading to a high ethanol yield of 0.41 g of ethanol/g of glucose.

scholarly journals Utilization of Biomass Derived from Cyanobacteria-Based Agro-Industrial Wastewater Treatment and Raisin Residue Extract for Bioethanol Production

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 486
Author(s):  
Olga N. Tsolcha ◽  
Vasiliki Patrinou ◽  
Christina N. Economou ◽  
Marianna Dourou ◽  
George Aggelis ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Acid Hydrolysis ◽  
Fossil Fuels ◽  
Ethanol Yield ◽  
Dairy Wastewater ◽  
Filamentous Cyanobacterium ◽  
Bioethanol Production ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sugar Release ◽  
Theoretical Ethanol Yield

Biofuels produced from photosynthetic microorganisms such as microalgae and cyanobacteria could potentially replace fossil fuels as they offer several advantages over fuels produced from lignocellulosic biomass. In this study, energy production potential in the form of bioethanol was examined using different biomasses derived from the growth of a cyanobacteria-based microbial consortium on a chemical medium and on agro-industrial wastewaters (i.e., dairy wastewater, winery wastewater and mixed winery–raisin effluent) supplemented with a raisin residue extract. The possibility of recovering fermentable sugars from a microbial biomass dominated by the filamentous cyanobacterium Leptolynbgya sp. was demonstrated. Of the different acid hydrolysis conditions tested, the best results were obtained with sulfuric acid 2.5 N for 120 min using dried biomass from dairy wastewater and mixed winery–raisin wastewaters. After optimizing sugar release from the microbial biomass by applying acid hydrolysis, alcoholic fermentation was performed using the yeast Saccharomyces cerevisiae. Raisin residue extract was added to the treated biomass broth in all experiments to enhance ethanol production. Results showed that up to 85.9% of the theoretical ethanol yield was achieved, indicating the potential use of cyanobacteria-based biomass in combination with a raisin residue extract as feedstock for bioethanol production.

scholarly journals Conversion of biomass to biofuels and life cycle assessment: a review

2021 ◽  
Author(s):  
Ahmed I. Osman ◽  
Neha Mehta ◽  
Ahmed M. Elgarahy ◽  
Amer Al-Hinai ◽  
Ala’a H. Al-Muhtaseb ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Biomass Conversion ◽  
Biofuel Production ◽  
Process Efficiency ◽  
Liquid Fuels ◽  
Thermochemical Processes ◽  
Lower Temperature

AbstractThe global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.

scholarly journals Pretreatments of lignocellulosic feedstock for bioethanol production

2010 ◽  
Vol 64 (4) ◽  
pp. 283-293 ◽  
Author(s):  
Zlatica Predojevic
Keyword(s):  
Renewable Energy ◽  
Co2 Emission ◽  
Fossil Fuels ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Bioethanol Production ◽  
Environment Protection ◽  
Lignocellulosic Feedstock ◽  
Lignocellulosic Feedstocks

The use of renewable energy sources (biofuels), either as a component in the conventional fossil fuels, gasoline and diesel, or as a pure biofuel, contributes to energy saving and decrease of total CO2 emission. The use of bioethanol mixed with gasoline significantly decreases gasoline consumption and contributes to environment protection. One of the problems in the production of bioethanol is the availability of sugar and starch based feedstock used for its production. However, lignocellulosic feedstocks are becoming more significant in the production of bioethanol due to their availability and low cost. The aim of this study is to point out the advantages and shortcomings of pretreatment processes and hydrolyses of lignocellulosic feedstocks that precede their fermentation to bioethanol.

scholarly journals Evaluation of polyploid miscanthus lines usage efficiency as a feedstock for bioethanol production

2021 ◽  
Vol 29 ◽  
pp. 13-19
Author(s):  
R. Y. Blume ◽  
O.V. Melnychuk ◽  
S.P. Ozheredov ◽  
D.B. Rakhmetov ◽  
Y.B. Blume
Keyword(s):  
Sweet Sorghum ◽  
Second Generation ◽  
Ethanol Yield ◽  
Bioenergy Crops ◽  
Control Line ◽  
Bioethanol Production ◽  
Second Generation Bioethanol ◽  
Giant Miscanthus ◽  
First And Second Generation ◽  
Bioethanol Yield

Aim. Main aim of this research was the evaluation of theoretical bioethanol yield (per ha) from hexaploid giant miscanthus (Miscanthus х giganteus) and further comparison with conventional triploid form as well as with other bioethanol crops. Methods. Several mathematic functions were determined that describe yearly yield dynamics and equations, which were used in calculations of theoretical bioethanol yield. Results. The theoretical bioethanol yield was evaluated for different hexaploid miscanthus lines. The most productive in terms of ethanol yield were lines 108 and 202, from which potential bioethanol yield was found to be higher than in control line (6451 L/ha) by 10.7 % and 14.2% respectively and can reach 7144 L/ha and 7684 L/ha. Conclusions. It was determined that the most productive lines of polyploid miscanthus (lines 108 and 202) are able to compete with other plant cellulosic feedstocks for second-generation bioethanol production in Ukraine. However, these lines show bioethanol productivity than sweet sorghum, in the case when sweet sorghum is processed for obtainment of both first- and second-generation bioethanol. Keywords: bioenergy crops, biofuels, giant miscanthus, Miscanthus, polyploidy, second-generation bioethanol.

scholarly journals The role of maize hybrids in current trends of bioethanol production

2020 ◽  
Vol 26 (2) ◽  
pp. 21-29
Author(s):  
Valentina Nikolić ◽  
Slađana Žilić ◽  
Milica Radosavljević ◽  
Marijana Simić
Keyword(s):  
Fossil Fuels ◽  
Raw Materials ◽  
Alternative Fuel ◽  
Bioethanol Production ◽  
Economic Activities ◽  
Fuel Production ◽  
Gasoline Demand ◽  
Current Trends ◽  
Production And Consumption

Bioethanol is a biofuel that is mostly used as a replacement for fossil fuels worldwide with yearly production reaching nearly 110 billion liters in 2019. Trends of producing this alternative fuel are rising and maize is considered as one of the best renewable raw materials for the production of fuel ethanol due to the high content of starch in the grain. Taking into account that Serbia is one of the most prominent maize producers in Europe, the surpluses of this crop could be directed towards bioethanol production. Even though there is no organized production and consumption of bioethanol as an automotive fuel in Serbia, the Serbian Government has recently introduced some new regulations regarding biofuels. However, due to the reduction of economic activities since the onset of COVID-19 pandemic in 2020, the global demand for crude oil has fallen sharply, negatively affecting the gasoline demand, and thus for bioethanol, which makes the future of this alternative fuel production notably uncertain.

scholarly journals Effect of Pre-hydrolysis on Simultaneous Saccharification and Fermentation of Native Rye Starch

2020 ◽  
Vol 13 (6) ◽  
pp. 923-936 ◽  
Author(s):  
Ewelina Strąk-Graczyk ◽  
Maria Balcerek
Keyword(s):  
Dry Matter ◽  
Agricultural Sector ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
Matter Content ◽  
Raw Material ◽  
Process Efficiency ◽  
Dry Matter Content ◽  
Sem Images ◽  
Simultaneous Saccharification

Abstract The rising population and increasing demand for food place added pressure on the agricultural sector to maintain high process efficiency while implementing environmentally friendly methods. In this study, we investigate the effect of pre-hydrolysis of native rye starch and its influence on the yield of ethanol obtained by simultaneous saccharification and fermentation (SSF) from high gravity rye mashes with 25% and 28% w w−1 dry matter content. Fermentation was carried out in a 3-day system at a temperature of 35 ± 1 °C using the dry distillery yeast Ethanol Red (Saccharomyces cerevisiae). The characteristics of the tested raw material and changes in the native rye starch during enzymatic hydrolysis were analyzed using a scanning electron microscope (SEM). The SEM images revealed characteristic changes on the surface of the starch, which was found to have a layered structure, as well as interesting behavior by the yeast during SSF when the glucose concentration in the environment was lowered. Both in the mashes with 25% and 28% w w−1 dry matter, starch pre-hydrolysis did not significantly increase either the initial amounts of sugars available to the yeast or the fermentation efficiency and ethanol yield in comparison to the mashes without this pre-treatment.

scholarly journals Evaluation of Copper-Contaminated Marginal Land for the Cultivation of Vetiver Grass (Chrysopogon zizanioides) as a Lignocellulosic Feedstock and its Impact on Downstream Bioethanol Production

2019 ◽  
Vol 9 (13) ◽  
pp. 2685 ◽  
Author(s):  
Emily M. Geiger ◽  
Dibyendu Sarkar ◽  
Rupali Datta
Keyword(s):  
Contaminated Soil ◽  
Ethanol Yield ◽  
Dilute Acid Pretreatment ◽  
Cellulose Content ◽  
Bioethanol Production ◽  
Vetiver Grass ◽  
Acid Pretreatment ◽  
Biofuel Feedstock ◽  
Lignocellulosic Feedstock ◽  
The Impact

Metal-contaminated soil could be sustainably used for biofuel feedstock production if the harvested biomass is amenable to bioethanol production. A 60-day greenhouse experiment was performed to evaluate (1) the potential of vetiver grass to phytostabilize soil contaminated with copper (Cu), and (2) the impact of Cu exposure on its lignocellulosic composition and downstream bioethanol production. Dilute acid pretreatment, enzymatic hydrolysis, and fermentation parameters were optimized sequentially for vetiver grass using response surface methodology (RSM). Results indicate that the lignocellulosic composition of vetiver grown on Cu-rich soil was favorably altered with a significant decrease in lignin and increase in hemicellulose and cellulose content. Hydrolysates produced from Cu exposed biomass achieved a significantly greater ethanol yield and volumetric productivity compared to those of the control biomass. Upon pretreatment, the hemicellulosic hydrolysate showed an increase in total sugars per liter by 204.7% of the predicted yield. After fermentation, 110% of the predicted ethanol yield was obtained for the vetiver grown on Cu-contaminated soil. By contrast, for vetiver grown on uncontaminated soil a 62.3% of theoretical ethanol yield was achieved, indicating that vetiver has the potential to serve the dual purpose of phytoremediation and biofuel feedstock generation on contaminated sites.

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