scholarly journals Ethanol Production from Hydrolyzed Kraft Pulp by Mono- and Co-Cultures of Yeasts: The Challenge of C6 and C5 Sugars Consumption

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 744 ◽  
Author(s):  
Rita H. R. Branco ◽  
Mariana S. T. Amândio ◽  
Luísa S. Serafim ◽  
Ana M. R. B. Xavier
Keyword(s):  
Ethanol Production ◽  
Kraft Pulp ◽  
Ethanol Yield ◽  
High Yield ◽  
Glucose Yield ◽  
Erlenmeyer Flask ◽  
Second Generation Bioethanol ◽  
Separate Hydrolysis And Fermentation ◽  
Chemical Pulping ◽  
Hydrolysis Of

Second-generation bioethanol production’s main bottleneck is the need for a costly and technically difficult pretreatment due to the recalcitrance of lignocellulosic biomass (LCB). Chemical pulping can be considered as a LCB pretreatment since it removes lignin and targets hemicelluloses to some extent. Chemical pulps could be used to produce ethanol. The present study aimed to investigate the batch ethanol production from unbleached Kraft pulp of Eucalyptus globulus by separate hydrolysis and fermentation (SHF). Enzymatic hydrolysis of the pulp resulted in a glucose yield of 96.1 ± 3.6% and a xylose yield of 94.0 ± 7.1%. In an Erlenmeyer flask, fermentation of the hydrolysate using Saccharomyces cerevisiae showed better results than Scheffersomyces stipitis. At both the Erlenmeyer flask and bioreactor scale, co-cultures of S. cerevisiae and S. stipitis did not show significant improvements in the fermentation performance. The best result was provided by S. cerevisiae alone in a bioreactor, which fermented the Kraft pulp hydrolysate with an ethanol yield of 0.433 g·g−1 and a volumetric ethanol productivity of 0.733 g·L−1·h−1, and a maximum ethanol concentration of 19.24 g·L−1 was attained. Bioethanol production using the SHF of unbleached Kraft pulp of E. globulus provides a high yield and productivity.

Expression of serpins by Clostridium thermocellum and simultaneous saccharification of lignocellulosic biomass to enhance ethanol production

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8662-8676
Author(s):  
Maria Mushtaq ◽  
Muhammad Javaid Asad ◽  
Muhammad Zeeshan Hyder ◽  
Syed Muhammad Saqlan Naqvi ◽  
Saad Imran Malik ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Wheat Straw ◽  
Corn Stover ◽  
Rice Straw ◽  
Clostridium Thermocellum ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Yeast Fermentation ◽  
Second Generation Bioethanol ◽  
Simultaneous Saccharification

Utilization of biomass for production of second generation bioethanol was considered as a way to reduce burdens of fossil fuel in Pakistan. The materials wheat straw, rice straw, cotton stalk, corn stover, and peel wastes were used in this experiment. Various parameters, such as acidic and alkali pretreatment, enzymatic hydrolysis by cellulases, and effect of proteases inhibitors on ethanol production, were examined. Fermentation was completed by the yeasts Saccharomyces cerevisiae and Clostridium thermocellum separately, and their ethanol production were compared and maximum ethanol yield was obtained with wheat straw i.e.,11.3 g/L by S. cerevisiae and 8.5 g/L by C. thermocellum. Results indicated that a higher quantity of sugar was obtained from wheat straw (19.6 ± 1.6 g/L) followed by rice straw (17.6 ± 0.6 g/L) and corn stover (16.1 ± 0.9 g/L) compared to the other evaluated biomass samples. A higher yield of ethanol (11.3 g/L) was observed when a glucose concentration of 21.7 g/L was used, for which yeast fermentation efficiency was 92%. Results also revealed the increased in ethanol production (93%) by using celluases in combination with recombinant Serine protease inhibitors from C. thermocellum. It is expected that the use of recombinant serpins with cellulases will play a major role in the biofuel production by using agricultural biomass. This will also help in the economics of the biofuel.

Hydrolysis of S. platensis Using Sulfuric Acid for Ethanol Production

2022 ◽  
Vol 1048 ◽  
pp. 451-458
Author(s):  
Megawati ◽  
Astrilia Damayanti ◽  
Radenrara Dewi Artanti Putri ◽  
Zuhriyan Ash Shiddieqy Bahlawan ◽  
Astika Arum Dwi Mastuti ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Ethanol Production ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Second Step ◽  
Carbohydrate Composition ◽  
Hydrolysis Time ◽  
Glucose Yield ◽  
Hydrolysis Temperature ◽  
Hydrolysis Of

S. platensis is a microalga that contains carbohydrate composition of 30.21% which makes it potential to be used as raw material for ethanol production. Hydrolysis of S. platensis is the first step for converting its carbohydrates into monosaccharides. The second step is fermentation of monosaccharides into ethanol. This research aims to study the effect of temperature and microalgae concentration on the hydrolysis of S. platensis using sulfuric acid as catalyst. This research was conducted using 300 mL sulfuric acid of 2 mol/L, hydrolysis temperatures of 70, 80 and 90 °C, and microalgae concentrations of 20, 26.7, and 33.3 g/L. The effect of temperature is significant in the hydrolysis of S. platensis using sulfuric acid. At microalgae concentration of 20 g/L and hydrolysis time of 35 minutes, the higher the temperatures (70, 80, and 90 °C), the more the glucose yields would be (8.9, 13.5, and 22.9%). This temperature effect got stronger when the hydrolysis was running for 15 minutes. Every time the hydrolysis temperature increased by 10 °C, the glucose yield increased by 13.0% at microalgae concentration of 33.3 g/L. At temperature of 90 °C and time of 35 minutes, the higher the microalgae concentrations (20, 26.7, and 33.3 g/L), the higher the glucose yields would be (25.5, 27.7, and 28.2%). The highest glucose concentration obtained was 2.82 g/L at microalgae concentration of 33.3 g/L, temperature of 90 °C, and time of 35 minutes.

scholarly journals Potential Utilization of Low Quality Sweet Potato for Bioethanol Production by Saccharomyces cerevisiae TISTR5339

2020 ◽  
Vol 17 (9) ◽  
pp. 933-946
Author(s):  
Supasit CHOOKLIN ◽  
Parichat NINUP-PATHAM ◽  
Saovanee CHOOJIT
Keyword(s):  
Ethanol Production ◽  
Acid Hydrolysis ◽  
Sweet Potato ◽  
Ammonium Sulphate ◽  
Ethanol Yield ◽  
Scale Up ◽  
Inoculum Size ◽  
Sulphate Content ◽  
Box Behnken Design ◽  
Hydrolysis Of

This study was aimed to investigate the optimal condition of ethanol production that has 2 major stages: acid hydrolysis and fermentation processes. These processes came from low quality sweet potato (LQSP) which was destroyed by the sweet potato weevil. The main compositions of LQSP were starch and fiber which consist of 55.25 and 10.29 %, respectively. In this case, the starch can be hydrolyzed to reduce the sugar, followed by the fermentation of the reduced sugar to ethanol. For this experiment, the effecting factors on acid hydrolysis of LQSP and the ethanol fermentation condition were optimized by S. cerevisiae using Response Surface Methodology (RSM) with Box-Behnken design in order to maximize ethanol yield. It was found that the maximum reducing sugar concentration of 390.99 ± 5.35 g/L was obtained from the hydrolysis condition with 1 % (v/v) of sulfuric acid and 25 % (w/v) of LQSP. Accordingly, the effects of ammonium sulphate content (0.05 - 0.15 %), pH (4.5 - 5.5) and inoculum content (5 - 10 %) on ethanol production was determined by RSM using Box-Behnken experiment design with a total 17 sets of all trials. The results were found that the maximum experimental ethanol productivity of 5.98 g/L was obtained from the condition at 0.05 % of ammonium sulphate, pH 5.5 and 5.0 % of inoculum size to 90 mL LQSP based medium and incubated at 30 °C for 48 h. In addition, the scale-up of ethanol production was studied in 9 L fermenter which provided the maximum ethanol yield of 5.04 g/L. Therefore, it can be concluded that LQSP had a potential as a substrate for ethanol production.

scholarly journals High yield of ethanol production by the strain Fusarium sp. ZW-21 with corncob hydrolysate

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 622-632
Author(s):  
Xiaohui Liang ◽  
Hongyu Si ◽  
Dongliang Hua ◽  
Yuxiao Zhao
Keyword(s):  
Ethanol Production ◽  
Yeast Extract ◽  
Incubation Temperature ◽  
Ethanol Yield ◽  
Inoculum Size ◽  
Effect Of Temperature ◽  
High Yield ◽  
Polysorbate 80 ◽  
Corncob Hydrolysate ◽  
Fusarium Sp

The filamentous fungus strain Fusarium sp. ZW-21 was used for ethanol production with corncob hydrolysate. The fermentation conditions of ethanol production from corncob hydrolysate by the strain were investigated, and the effect of temperature, pH, nitrogen source, and surfactants on the ethanol production was investigated. The two factors yeast extract and polysorbate 80 were selected for further optimization by response surface methodology. The optimal conditions for ethanol production by the strain Fusarium sp. ZW-21 were 50 g/L sugar of corncob hydrolysate, 10.35 g/L yeast extract, 10 g/L KH2PO4, 0.5 g/L MgSO4·7H2O, 0.38 g/L polysorbate 80, pH 6.0, inoculum size of 1 mL/50 mL medium, and incubation temperature of 30 °C. The fermentation period was 5 d under oxygen-limited conditions, and the ethanol yield was 24.2 g/L.

Improvement in Ethanol Yield from Lignocellulo-Starch Biomass using Saccharomyces cerevisiae alone or its Co-culture with Scheffersomyces stipitis

2020 ◽  
Vol 9 (1) ◽  
pp. 57-76
Author(s):  
Madhanamohanan G. Mithra ◽  
Gouri Padmaja
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Relative Advantage ◽  
Vegetable Crops ◽  
Fed Batch ◽  
Scheffersomyces Stipitis ◽  
Separate Hydrolysis And Fermentation ◽  
Ethanol Yields ◽  
Sugar Levels

Background: Literature on ethanol production from Lignocellulo-Starch Biomass (LCSB) containing starch besides cellulose and hemicellulose, is scanty. Fed-Batch Separate Hydrolysis And Fermentation (F-SHF) was earlier found more beneficial than Fed-Batch Simultaneous Saccharification and Fermentation (F-SSF). Objective: The study aimed at modification of the saccharification and fermentation strategies by including a prehydrolysis step prior to the SSF and compared the ethanol yields with co-culture fermentation using hexose-fermenting Saccharomyces cerevisiae and pentose-fermenting Scheffersomyces stipitis. Methods: Fed-batch hybrid-SSF and Fed-Batch Separate Hydrolysis and Co-culture Fermentation (F-SHCF) in improving ethanol yield from Steam (ST) or Dilute Sulfuric Acid (DSA) pretreated LCSBs (peels of root and vegetable crops) were studied. Results: There was a progressive build-up of ethanol during F-HSSF up to 72h and further production up to 120h was negligible, with no difference among pretreatments. Despite very high ethanol production in the initial 24h of fermentation by S.cerevisiae under F-SHCF, the further increase was negligible. A rapid hike in ethanol production was observed when S. stipitis was also supplemented because of xylose conversion to ethanol. Conclusion: While ST gave higher ethanol (296-323 ml/kg) than DSA under F-HSSF, the latter was advantageous under F-SHCF for certain residues. Prehydrolysis (24h; 50°C) enhanced initial sugar levels favouring fast fermentation and subsequent saccharification and fermentation occurred concurrently at 37°C for 120h, thus leading to energy saving and hence F-HSSF was advantageous. Owing to the low hemicellulose content in LCSBs, the relative advantage of co-culture fermentation over monoculture fermentation was not significant.

scholarly journals Enzymatic depolymerization of wheat straw polysaccharides

2021 ◽  
Vol 939 (1) ◽  
pp. 012005
Author(s):  
Zh Makhatov ◽  
N Alibayev ◽  
Z Konarbayeva ◽  
B Makhatov ◽  
A Makhatova ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Specific Activity ◽  
Maximum Yield ◽  
High Yield ◽  
Cellulolytic Enzymes ◽  
Cultivation Conditions ◽  
Glucose Yield ◽  
Complex Preparation ◽  
Hydrolysis Of ◽  
Enzymatic Depolymerization

Abstract The purpose of this study is to develop a technology for enzymatic processing for depolymerization of polysaccharides in wheat straw to obtain the maximum yield of glucose and sorbitol. Cellulolytic enzymes endo-1,4-β-glucanase (EC 3.2.1.4) and cellobiose (1,3-β-glucosidase) (CF 3.2.1.21) were isolated and studied in local strains Tr. viride 121, which are grown under deep cultivation conditions. A technology has been developed for obtaining a complex preparation “Cellozyme G20x” with a high yield and specific activity of cellulase, xylanase, β-glucanase and pectinase, and a scheme for purification from cellulases by precipitation, ultrafiltration, and freeze drying is not inferior in efficiency to commercial preparations. The physicochemical properties of the preparation “Cellozyme G20x” have been studied, the optimal parameters of the action and stability of the enzyme preparation have been established. The efficiency of Cellozyme G20x for hydrolysis of straw polysaccharides was 35-40% in terms of glucose yield.

Comparative Study of Artificial Neural Network (ANN) and Response Surface Methodology (RSM) on Optimization of Ethanol Production from Sawdust

2017 ◽  
Vol 30 ◽  
pp. 125-133 ◽  
Author(s):  
Akindele Okewale ◽  
Olusola Adesina ◽  
Mustapha Oloko-Oba
Keyword(s):  
Ethanol Production ◽  
Ethanol Yield ◽  
Ann Model ◽  
Empirical Methods ◽  
Box Behnken Design ◽  
Saw Dust ◽  
Separate Hydrolysis And Fermentation ◽  
Ann Models ◽  
Artificial Neural Network Ann ◽  
Rsm Model

This work focused on optimization of production of ethanol from saw dust using two empirical methods, the ANN and the RSM. It further investigated the modeling and optimization efficiencies of RSM and ANN in separate hydrolysis and fermentation of sawdust for ethanol production. Box - Behnken Design (BBD) was used to generate 17 individual experiments which were carried out, RSM and Genetic Algorithm (GA) of ANN which were used to optimize the production which was then compared. The optimum concentrations of ethanol yield predicted were 56.968 wt. % and 57. 387263 wt. % for RSM and ANN models respectively. R2 value obtained for ANN model was 0.9989 while R2 value of 0.9046 was obtained for RSM model. The Root Mean Square Error (RMSE) value for ANN was found to be 0.143 while the RMSE value for RSM was 2.17. It showed that ANN had relatively higher predictive model ability and thus shows to be a better optimization tool for the ethanol from saw dust compared to RSM which also a good modelling tool.

scholarly journals Fungal Pretreatment of Sugarcane Bagasse: A Green Pathway to Improve Saccharification and Ethanol Production

2021 ◽  
Author(s):  
Caroline Hartmann ◽  
Roselei Claudete Fontana ◽  
Félix Gonçalves de Siqueira ◽  
Marli Camassola
Keyword(s):  
Fourier Transform ◽  
Enzymatic Hydrolysis ◽  
Ethanol Production ◽  
Sugarcane Bagasse ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Biological Pretreatment ◽  
Fungal Pretreatment ◽  
Hydrolysis Of ◽  
Positive Effect

Abstract Biological pretreatment was investigated to increase ethanol production from lignocellulosic biomass, like sugarcane bagasse. Enzyme secretion, changes in substrate composition, enzymatic hydrolysis and ethanol yield after pretreatment by different basidiomycetes were evaluated. Analysis by Fourier transform infrared spectroscopy showed that P. pulmonarius PS2001 and T. villosa 82I6 promoted more extensive selective modifications in the lignin content. Glucose release during enzymatic hydrolysis of samples pretreated with P. pulmonarius PS2001 for 35, 42 and 49 days and with T. villosa 82I6 for 21, 28 and 49 days were higher than the control (48.5±2.38 mg/g), i.e. 68.4 ±0.7, 76.3 ±1.6 and 76.5±2.1 mg/g and 70.9±8.3, 77.8±5.8 and 77.6±4.2 mg/g, respectively. During the fermentation of hydrolysates of samples pretreated with T. villosa 82I6 for 28 and 49 days, a maximum ethanol yield of 19.1±2.8 and 20.2±0.5 mg/g, respectively, was achieved. A positive effect of biological pretreatment on hydrolysis and fermentation was demonstrated.

Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN
Keyword(s):  
Acetic Acid ◽  
Betula Pendula ◽  
Cooking Time ◽  
Hot Water ◽  
Partial Hydrolysis ◽  
Chemical Pulping ◽  
Black Liquors ◽  
Aliphatic Carboxylic Acids ◽  
Hydrolysis Of ◽  
Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

scholarly journals Enzymatic Process for Cystoseira barbata Valorization: Ethanol Production and Additional By-Products

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 741
Author(s):  
Doinita-Roxana Cioroiu Tirpan ◽  
Ancaelena Eliza Sterpu ◽  
Claudia Irina Koncsag ◽  
Alina Georgiana Ciufu ◽  
Tănase Dobre
Keyword(s):  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Product Yield ◽  
Liquid Ratio ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cystoseira Barbata ◽  
Main Factors ◽  
Process Factors

The aim of this study is to evaluate the potential of dried Cystoseira barbata alga for ethanol production through alcoholic fermentation. The influence of the main factors affecting the fermentation are studied in the frame of a 23 factorial experimental plan. The main factors influencing the process are the fermentation temperature (t from 25 °C to 35 °C), the solid to liquid ratio (S/L from 0.040 g/g to 0.080 g/g), and the cellulase ratio (R from 8 U/g d.m to 16 U/g d.m.). The maximum volatile compounds yield of 0.2808 g/g d.m and ethanol yield of 0.0158 g/g d.m were favored by the following experimental conditions: process temperature of 35 °C, solid to liquid ratio of 0.0415, and enzyme ratio of 16 U/g d.m. A statistical model was used to correlate the product yield with the process factors. Additionally, 19 interesting bioactive compounds were found in the enzymatic hydrolysis and alcoholic fermentation broths which seem likely to maintain natural defence mechanisms against diseases and physical disorders.

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