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 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 Evaluating and engineering Saccharomyces cerevisiae promoters for increased amylase expression and bioethanol production from raw starch

2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Marthinus W Myburgh ◽  
Shaunita H Rose ◽  
Marinda Viljoen-Bloom
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Corn Starch ◽  
Consolidated Bioprocessing ◽  
Ethanol Yield ◽  
Small Scale ◽  
Bioethanol Production ◽  
Raw Starch ◽  
Broken Rice ◽  
Available Carbon ◽  
Theoretical Ethanol Yield

ABSTRACT Bioethanol production from starchy biomass via consolidated bioprocessing (CBP) will benefit from amylolytic Saccharomyces cerevisiae strains that produce high levels of recombinant amylases. This could be achieved by using strong promoters and modification thereof to improve gene expression under industrial conditions. This study evaluated eight endogenous S. cerevisiae promoters for the expression of a starch-hydrolysing α-amylase gene. A total of six of the native promoters were modified to contain a promoter-proximal intron directly downstream of the full-length promoter. Varying results were obtained; four native promoters outperformed the ENO1P benchmark under aerobic conditions and two promoters showed better expression under simulated CBP conditions. The addition of the RPS25A intron significantly improved the expression from most promoters, displaying increased transcript levels, protein concentrations and amylase activities. Raw starch-utilising strains were constructed through co-expression of selected α-amylase cassettes and a glucoamylase gene. The amylolytic strains displayed improved fermentation vigour on raw corn starch and broken rice, reaching 97% of the theoretical ethanol yield and converting 100% of the available carbon to products within 120 h in small-scale CBP fermentations on broken rice. This study showed that enhanced amylolytic strains for the conversion of raw starch to ethanol can be achieved through turnkey promoter selection and/or engineering.

scholarly journals Acid Hydrolysis of Lignocellulosic Materials for The Production of Second Generation Ethanol

2021 ◽  
Author(s):  
Mariane Daniella Silva ◽  
João Pedro Cano ◽  
Fernanda Maria Pagane Guereschi Ernandes ◽  
Crispin Humberto Garcia-Cruz
Keyword(s):  
Acid Hydrolysis ◽  
Agricultural Production ◽  
Fossil Fuels ◽  
Second Generation ◽  
Reducing Sugars ◽  
Lignocellulosic Materials ◽  
Sugar Release ◽  
Different Types ◽  
Hydrolysis Of ◽  
Second Generation Ethanol

Abstract Brazil is one of the countries with the largest agricultural production in the world. Therefore, it is capable of generating large amounts of agro-industrial waste that can be used as biomass for the production of biofuels. Second generation ethanol is a renewable energy alternative, capable of replacing fossil fuels. Within this context, the objective of the present work was to study the effect of diluted acid hydrolysis in different types of lignocellulosic residues and the consequent production of 2G ethanol from these hydrolysates using different fermenting microorganisms. The acid concentration that released the highest content of fermentable sugars from the acid hydrolysis of lignocellulosic materials was 5.0% of sulfuric acid and the contact time with the biomass was 15 min. while heating in autoclave. The material that showed the highest sugar release after acid hydrolysis was cassava residues, with 131.09 g.L− 1 of reducing sugars. The fermentations were carried out with microorganisms alone and also in consortium. The largest production of 2G ethanol was from the hydrolyzate of soybean hulls, of 47.70 g.L− 1 of ethanol by the consortium of Zymomonasmobilis and Candida tropicalis, during 8 h of fermentation and showed productivity of 5.96 g.L− 1.h− 1.

scholarly journals Production of bioethanol from sago hampas via Simultaneous Saccharification and Fermentation (SSF)

2018 ◽  
Vol 10 (4) ◽  
pp. 240-245 ◽  
Author(s):  
HUANG CHAI HUNG ◽  
DAYANG SALWANI AWANG ADENI ◽  
QUEENTETY JOHNNY ◽  
MICKY VINCENT
Keyword(s):  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Yield ◽  
Cellulolytic Enzymes ◽  
Total Biomass ◽  
Bioethanol Production ◽  
Amylolytic Enzymes ◽  
Theoretical Ethanol Yield ◽  
Waste Accumulation ◽  
Biomass Reduction ◽  
Simultaneous Saccharification

Huang CH, Adeni DSA, Johnny Q, Vincent M. 2018. Production of bioethanol from sago hampas via Simultaneous Saccharification and Fermentation (SSF). Nusantara Bioscience 10: 240-245. Sago hampas is an inexpensive, renewable and abundant agro-industrial residue that can be exploited to produce bioethanol. In this study, ethanol production was performed via simultaneous saccharification and fermentation (SSF) on fresh sago hampas at 2.5%, 5.0% and 7.5% (w/v) feedstock loadings with the aid of amylolytic enzymes, cellulolytic enzymes and Saccharomyces cerevisiae, under anaerobic condition for five days with a constant agitation of 150 rpm and ambient temperature. Results obtained indicated that SSF with 5.0% (w/v) sago hampas loading produced the highest ethanol yield at 17.79 g/L (79.65% Theoretical Ethanol Yield, TEY), while SSF using 2.5% and 7.5% (w/v) sago hampas produced ethanol at only 8.38 g/L (75.00% TEY) and 23.28 g/L (69.48% TEY), respectively. Total biomass reduction was recorded between 66.3% to 71.3% by the end of the SSF period. This study demonstrated that fresh sago hampas is a promising feedstock for bioethanol production as yields are generally high for all the substrate loadings tested. Moreover, bioethanol production using fresh sago hampas may assist in reducing pollution caused by sago waste accumulation.

scholarly journals Bioethanol production from defatted biomass of Nannochloropsis oculata microalgae grown under mixotrophic conditions

2021 ◽  
Author(s):  
Nashwa Fetyan ◽  
Abo El-Khair B. El-Sayed ◽  
Fatma M. Ibrahim ◽  
Yasser Attia ◽  
Mahmoud W. Sadik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Ethanol Yield ◽  
Nannochloropsis Oculata ◽  
Enzymatic Treatment ◽  
Enzyme Hydrolysis ◽  
Control Treatment ◽  
Bioethanol Production ◽  
Microalgal Biomass

Abstract Microalgal biomass is one of the most promising third-generation feedstocks for bioethanol production because it contains significantly reduced sugar amounts which, by separate hydrolysis and fermentation, can be used as a source for ethanol production. In this study, the defatted microalgal biomass of Nannochloropsis oculata (NNO-1 UTEX Culture LB 2164) was subjected to bioethanol production through acid digestion and enzymatic treatment before being fermented by Saccharomyces cerevisiae (NRRLY-2034). For acid hydrolysis (AH), the highest carbohydrate yield 252.84 mg/g DW was obtained with 5.0% (v/v) H2SO4 at 121°C for 15 min for defatted biomass cultivated mixotrophically on SBAE with respect to 207.41 mg/g DW for defatted biomass cultivated autotrophically (control treatment), Whereas, the highest levels of reducing sugars was obtained With 4.0%(v/v) H2SO4 157.47 ± 1.60 mg/g DW for defatted biomass cultivated mixotrophically in compared with 135.30 mg/g DW for the defatted control treatment. The combination of acid hydrolysis 2.0% (v/v) H2SO4 followed by enzymatic treatment (AEH) increased the carbohydrate yields to 268.53 mg/g DW for defatted biomass cultivated mixotrophically on SBAE with respect to 177.73 mg/g DW for the defatted control treatment. However, the highest levels of reducing sugars were obtained with 3.0% (v/v) H2SO4 followed by enzyme treatment gave 232.39 ± 1.77 for defatted biomass cultivated mixotrophically on SBAE and 150.75 mg/g DW for the defatted control treatment. The sugar composition of the polysaccharides showed that glucose was the principal polysaccharide sugar (60.7%-62.49%) of N. oculata defatted biomass. Fermentation of the hydrolysates by Saccharomyces cerevisiae for the acid pretreated defatted biomass samples gave ethanol yield of 0.86 g/l (0.062 g/g sugar consumed) for control and 1.17 g/l (0.069 g/g sugar consumed) for SBAE mixotrophic. Whereas, the maximum ethanol yield of 6.17 ± 0.47 g/l (0.26 ± 0.11 g/g sugar consumed) was obtained with samples from defatted biomass grown mixotrophically (SBAE mixotrophic) pretreated with acid coupled enzyme hydrolysis.

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 Bioethanol Production from the Pods of Delonix Regia

2020 ◽  
Vol 9 (5) ◽  
pp. 1523-1527
Keyword(s):  
Substrate Concentration ◽  
Hplc Analysis ◽  
Fossil Fuels ◽  
Bioethanol Production ◽  
Fermentable Sugar ◽  
Yeast Saccharomyces Cerevisiae ◽  
Delonix Regia ◽  
Bioethanol Yield ◽  
High Cellulose ◽  
Different Doses

To replace conventional fossil fuels extensive research works are being carried out using bio-resources. In this scenario an experimental study was carried out to extract bioethanol from the seeds of the plant Delonix regia. . Delonix regia pod has several characteristics features like high cellulose and hemicelluloses content and that can be readily hydrolysed into fermentable sugar. In our present study the pods of D.regia were powdered and sterilised. The pod powder was treated with laboratory grown Sacchromyces cervisiae and allowed for fermentation. Different doses of Delonix regia pod powder was used (4, 8, 12, and 16%) to study their effect on ethanol fermentation by the yeast Saccharomyces cerevisiae. An increase in the substrate concentration was found to increase the bioethanol yield. The ethanol production was high after 24 hour of fermentation when the substrate concentration was 16%. Temperature between 30-35°C and pH4.5 are reported to be optimum for the growth of yeast and good bioethanol synthesis. HPLC analysis of the extracted sugar of the pod showed the presence of cellulose and hemicellulose. After distillation the produced bio ethanol was tested for its quality and found it well suited for fuel.

scholarly journals Optimized acid hydrolysis of the polysaccharides from the seaweed Solieria filiformis (Kützing) P.W. Gabrielson for bioethanol production

2017 ◽  
Vol 39 (4) ◽  
pp. 423 ◽  
Author(s):  
George Meredite Cunha de Castro ◽  
Norma Maria Barros Benevides ◽  
Maulori Curié Cabral ◽  
Rafael De Souza Miranda ◽  
Enéas Gomes Filho ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Kinetic Parameters ◽  
Renewable Resource ◽  
Bioethanol Production ◽  
Seaweed Species ◽  
Mild Conditions ◽  
Hydrolysis Of ◽  
Solieria Filiformis

 The seaweeds are bio-resource rich in sulfated and neutral polysaccharides. The tropical seaweed species used in this study (Solieria filiformis), after dried, shows 65.8% (w/w) carbohydrate, 9.6% (w/w) protein, 1.7% (w/w) lipid, 7.0% (w/w) moisture and 15.9% (w/w) ash. The dried seaweed was easily hydrolyzed under mild conditions (0.5 M sulfuric acid, 20 min.), generating fermentable monosaccharides with a maximum hydrolysis efficiency of 63.21%. Galactose and glucose present in the hydrolyzed were simultaneously fermented by Saccharomyces cerevisiae when the yeast was acclimated to galactose and cultivated in broth containing only galactose. The kinetic parameters of the fermentation of the seaweed hydrolyzed were Y(P⁄S) = 0.48 ± 0.02 g.g−1, PP = 0.27 ± 0.04 g.L−1.h−1, h = 94.1%, representing a 41% increase in bioethanol productivity. Therefore, S. filiformis was a promising renewable resource of polysaccharides easily hydrolyzed, generating a broth rich in fermentable monosaccharides for ethanol production. 

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