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Cellulosic ethanol

Arup Jyoti Borah, Mayank Agarwal, Arun Goyal, Vijayanand S Moholkar
Invasive weeds ubiquitously found in terrestrial and aquatic ecosystems form potential feedstock for lignocellulosic ethanol production. The present study has reported a bioprocess for production of ethanol using mixed feedstock of 8 invasive weeds found in India. The feedstock was subjected to pretreatment comprising dilute acid hydrolysis (for hydrolysis of hemicellulosic fraction), alkaline delignification and enzymatic hydrolysis of cellulosic fraction. Pentose-rich and hexose-rich hydrolyzates obtained from pretreatment were fermented separately using microbial cultures of S...
August 1, 2018: Ultrasonics Sonochemistry
Jingwen Qiu, Dong Tian, Fei Shen, Jinguang Hu, Yongmei Zeng, Gang Yang, Yanzong Zhang, Shihuai Deng, Jing Zhang
Phosphoric acid plus hydrogen peroxide (PHP) pretreatment was employed on wheat straw for ethanol conversion by simultaneous saccharification and fermentation (SSF) at high loadings. Results showed solid loading of PHP-pretreated wheat straw can be greatly promoted to 20%. Although more enzyme input improved ethanol conversion significantly, it still can be potentially reduced to 10-20 mg protein/g cellulose. Increasing yeast input also promoted ethanol conversion, however, the responses were not significant...
August 4, 2018: Bioresource Technology
Ninad Kothari, Evert K Holwerda, Charles M Cai, Rajeev Kumar, Charles E Wyman
Background: The thermophilic anaerobic bacterium Clostridium thermocellum is a multifunctional ethanol producer, capable of both saccharification and fermentation, that is central to the consolidated bioprocessing (CBP) approach of converting lignocellulosic biomass to ethanol without external enzyme supplementation. Although CBP organisms have evolved efficient machinery for biomass deconstruction, achieving complete solubilization requires targeted approaches, such as pretreatment, to prepare recalcitrant biomass feedstocks for further biological digestion...
2018: Biotechnology for Biofuels
Hongting Tang, Jiajing Wang, Shenghuan Wang, Yu Shen, Dina Petranovic, Jin Hou, Xiaoming Bao
BACKGROUND: The self-assembly of cellulosomes on the surface of yeast is a promising strategy for consolidated bioprocessing to convert cellulose into ethanol in one step. RESULTS: In this study, we developed a novel synthetic cellulosome that anchors to the endogenous yeast cell wall protein a-agglutinin through disulfide bonds. A synthetic scaffoldin ScafAGA3 was constructed using the repeated N-terminus of Aga1p and displayed on the yeast cell surface. Secreted cellulases were then fused with Aga2p to assemble the cellulosome...
August 7, 2018: Microbial Cell Factories
Ashwin Gaikwad
As the bioconversion of cellulosic substrate to fuels is essential to suppress the dependence on conventional fossil fuels, development of new improved bioprocess engineering techniques are requisite for fulfilling the rising demand of biofuels throughout the world. For this purpose, the effect of particle size on enzymatic hydrolysis of cotton cellulose has been explored in great detail. The model simulations for the enzymatic hydrolysis of microcrystalline cotton cellulose of different concentrations (0.25-20 mg/ml) were performed for the average particle size ranging from 0...
August 7, 2018: Applied Biochemistry and Biotechnology
Plínio R Rodrigues, Mateus F L Araújo, Tamarah L Rocha, Ronnie Von S Veloso, Lílian A Pantoja, Alexandre S Santos
The production of lignocellulosic ethanol is one of the most promising alternatives to fossil fuels; however, this technology still faces many challenges related to the viability of the lignocellulosic alcohol in the market. In this paper the endocarp of buriti fruit was assessed for ethanol production. The fruit endocarp was characterized physically and chemically. Acid and alkaline pre-treatments were optimized by surface response methodology for removal of hemicellulose and lignin from the biomass. Hemicellulose content was reduced by 88% after acid pretreatment...
2018: PeerJ
Diana L Osorio-Arrieta, José L Muñoz-Mata, Georgina Beltrán-Pérez, Juan Castillo-Mixcóatl, Claudia O Mendoza-Barrera, Víctor Altuzar-Aguilar, Severino Muñoz-Aguirre
This paper presents a new approach to reduce the measurement time by the prediction of the steady-state using the transient response to ethanol for quartz crystal microbalance gas sensors coated with ethyl cellulose. The experimentally measured response curves were successively fitted using a mathematical model based on the sum of two exponentials with different time constants. The parameters of the model were determined, and the time constants and the magnitude of the steady-state response were analyzed. Even though the time constants did not stabilize well, the parameter corresponding to the magnitude of the steady-state response quickly converged and stabilized after 37 s...
July 31, 2018: Sensors
R Spaccini, V Cozzolino, V Di Meo, D Savy, M Drosos, A Piccolo
The ligno-cellulose residues from biorefinery production of bio-ethanol were used as woody structuring material within an on-farm composting system, with the aim to obtain bioactive water soluble and humic fractions from composted materials. The molecular characterization of initial biomasses and final products revealed a transformation towards more stable compounds during composting and showed the selective incorporation of specific phenolic derivatives of ligno-cellulose in both bulk samples and corresponding extracts...
July 25, 2018: Science of the Total Environment
Camila A Rezende, Beatriz W Atta, Marcia C Breitkreitz, Rachael Simister, Leonardo D Gomez, Simon J McQueen-Mason
Background: Pretreatments are one of the main bottlenecks for the lignocellulose conversion process and the search for cheaper and effective pretreatment methodologies for each biomass is a complex but fundamental task. Here, we used a 2ν5-1 fractional factorial design (FFD) to optimize five pretreatment variables: milling time, temperature, double treatment, chemical concentration, and pretreatment time in acid-alkali (EA) and acid-organosolv (EO) pretreatments, applied to elephant grass leaves...
2018: Biotechnology for Biofuels
Qiang Yu, Aiping Zhang, Wen Wang, Long Chen, Ruxue Bai, Xinshu Zhuang, Qiong Wang, Zhongming Wang, Zhenhong Yuan
Here, the potential use of herbal residues of Akebia as feedstock for ethanol production is evaluated. Additionally, five deep eutectic solvents from hemicellulose-derived acids were prepared to overcome biomass recalcitrance. Reaction temperatures had more significant influences on solid loss and chemical composition than the molar ratios of choline chloride (ChCl) to derived acids. Glycolic acid resulted in the maximum levels of lignin, xylan and glucan removal, which were 60.0%, 100% and 71.5%, respectively, at 120°C with a 1:6M ratio of ChCl-glycolic acid...
January 2018: Bioresource Technology
Daniel de Castro Assumpção, Elmer Alberto Ccopa Rivera, Laura Plazas Tovar, Thaddeus Chukwuemeka Ezeji, Rubens Maciel Filho, Adriano Pinto Mariano
In flexible ethanol-butanol plants, low tolerance to butanol by solventogenic clostridia (and resulting dilute fermentation) results in considerable number of empty fermentors whenever production focuses on ethanol. This research identified scenarios in which vacuum fermentation (in-situ vacuum recovery) may be applied to solve this problem. We conducted ethanol (Saccharomyces cerevisiae) and ABE (Clostridium beijerinckii NCIMB 8052) batch vacuum fermentations of eucalyptus hydrolysates according to the distribution of sugars in a flexible plant...
July 26, 2018: Bioprocess and Biosystems Engineering
Sheila Montipó, Ignacio Ballesteros, Roselei Claudete Fontana, Siqing Liu, Ayrton Figueiredo Martins, Mercedes Ballesteros, Marli Camassola
Elephant grass was subjected to steam explosion to enhance cellulose accessibility and convert it into ethanol. After catalyzed pretreatment at 190 °C for 5 min, enzymatic hydrolysis was carried out using high rate of solid loading combined with different enzyme dosages. Assays employing 20% (w/v) solids loading and an enzyme dosage of 20 FPU g-1 substrate led to a yield of 86.02 g glucose released per 100 g potential glucose in the water insoluble solids. This condition was selected to carry out the simultaneous saccharification and fermentation procedure through S...
February 2018: Bioresource Technology
Dawit Beyene, Michael Chae, Jing Dai, Christophe Danumah, Frank Tosto, Abayneh Getachew Demesa, David C Bressler
Integrating enzymatic treatment and acid hydrolysis potentially improves the economics of cellulose nanocrystal (CNC) production and demonstrates a sustainable cellulosic ethanol co-generation strategy. In this study, the effect of enzymatic treatment on filter paper and wood pulp fibers, and CNCs generated via subsequent acid hydrolysis were assessed. Characterization was performed using a pulp quality monitoring system, scanning and transmission electron microscopies, dynamic light scattering, X-ray diffraction, and thermogravimetric analysis...
July 24, 2018: Materials
Xueling Zhang, Meng Liu, Xu Zhang, Tianwei Tan
In this paper, a novel strategy for lipid production through coupling oleaginous yeasts and activated sludge biological methods by cultivation of Rhodotorula glutinis in cellulosic ethanol wastewater was studied. Under optimal conditions in wastewater medium (dilution ratio of 1:2 and glucose supplement of 40 g/L), the maximum biomass and lipid content as well as the lipid yield reached 11.31 g/L, 18.35% and 2.08 g/L, with the associated removal rates of COD, TOC, NH4 + -N, TN and TP reaching 83.15%, 81...
July 17, 2018: Bioresource Technology
Jia-Qing Zhu, Xiao-Le Wu, Wen-Chao Li, Lei Qin, Si Chen, Tao Xu, Hong Liu, Xiao Zhou, Xia Li, Cheng Zhong, Bing-Zhi Li, Ying-Jin Yuan
This work investigated the effect of ethylenediamine pretreatment on reducing enzyme loading in high gravity fermentation. At optimal conditions of ethylenediamine pretreatment, 85.5% lignin was removed. Enzyme adsorption analysis using a fluorescent cellulose-binding protein showed 35.2% increase of productive adsorption of enzymes to ethylenediamine pretreated biomass, which was caused by high delignification and dramatically increased surface roughness and porosity. In SScF at 15% glucan loading, up to 82...
July 7, 2018: Bioresource Technology
Li Li, Philip W Dyer, H Christopher Greenwell
In this work, Pseudomonas cepacia lipase immobilized on cellulosic polyurethane was used as a catalyst for biodiesel production via trans-esterification reactions in order to provide cost-effective methods of enzyme recycling. The efficacy of the immobilized enzyme catalyst at low loading (6.2 wt %) and the effects of temperature, water content, and reaction time in model trans-esterification of glyceryl trioctanoate were investigated extensively. It was found that water was necessary for the reaction of glyceryl trioctanoate with ethanol to proceed...
June 30, 2018: ACS Omega
Meri J Lundahl, Ville Klar, Rubina Ajdary, Nicholas Norberg, Mariko Ago, Ana Gisela Cunha, Orlando J Rojas
A continuous and scalable method for the wet spinning of cellulose nanofibrils (CNFs) is introduced in a core/shell configuration. Control on the interfacial interactions was possible by the choice of the shell material and coagulant, as demonstrated here with guar gum (GG) and cellulose acetate (CA). Upon coagulation in acetone, ethanol, or water, GG and CA formed supporting polymer shells that interacted to different degrees with the CNF core. Coagulation rate was shown to markedly influence the CNF orientation in the filament and, as a result, its mechanical strength...
August 6, 2018: ACS Applied Materials & Interfaces
Lahiru N Jayakody, Jing-Jing Liu, Eun Ju Yun, Timothy Lee Turner, Eun Joong Oh, Yong-Su Jin
Simultaneous saccharification and fermentation (SSF) of cellulose via engineered Saccharomyces cerevisiae is a sustainable solution to valorize cellulose into fuels and chemicals. In this study, we demonstrate the feasibility of direct conversion of cellulose into ethanol and a bio-degradable surfactant, ethyl-β-d-glucoside, via an engineered yeast strain (i.e., strain EJ2) expressing heterologous cellodextrin transporter (CDT-1) and intracellular β-glucosidase (GH1-1) originating from Neurospora crassa. We identified the formation of ethyl-β-d-glucoside in SSF of cellulose by the EJ2 strain owing to transglycosylation activity of GH1-1...
July 16, 2018: Biotechnology and Bioengineering
Amanda M Williams-Rhaesa, Gabriel M Rubinstein, Israel M Scott, Gina L Lipscomb, Farris L Poole Ii, Robert M Kelly, Michael W W Adams
Caldicellulosiruptor bescii is an extremely thermophilic cellulolytic bacterium with great potential for consolidated bioprocessing of renewable plant biomass. Since it does not natively produce ethanol, metabolic engineering is required to create strains with this capability. Previous efforts involved the heterologous expression of the gene encoding a bifunctional alcohol dehydrogenase, AdhE, which uses NADH as the electron donor to reduce acetyl-CoA to ethanol. Acetyl-CoA produced from sugar oxidation also generates reduced ferredoxin but there is no known pathway for the transfer of electrons from reduced ferredoxin to NAD in C...
December 2018: Metabolic Engineering Communications
Nisha Singh, Anshu S Mathur, Ravi P Gupta, Colin J Barrow, Deepak Tuli, Munish Puri
The production of bioethanol was studied by the cultivation of Clostridium thermocellum ATCC 31924 in MTC medium including crystalline cellulose as the sole substrate. The effects of key operational parameters that affect bioethanol production from microcrystalline cellulose were optimized. Under optimum conditions (pH 8.0, temperature 55 °C, inoculum size 4% (v/v) and 0.5% (w/v) substrate concentration), a maximum ethanol yield of 0.30 g ethanol/g cellulose consumed and 95.32% cellulose conversion was obtained...
February 2018: Bioresource Technology
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