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The aim of this study was to determine the differences in grain and ethanol yields between hybrids obtained from breeding programs in the Republic of Croatia and introduced HTF (High Total Fermentable) maize hybrids. The trial was conducted at three sites (Osijek, Beli Manastir and Zagreb) for two consecutive years (2012 and 2013) in three plant densities (60,000, 70,000 and 80,000 plants/ha). Pioneer HTF hybrids for the ethanol production were used as controls to assess the productivity of ethanol of hybrids from the Agricultural Institute Osijek and Bc Institute d.d. The study of ethanol production was carried out by using the Lemuz method. According to ANOVA statistical analysis, statistically significant differences in grain and ethanol yields were not found between HTF hybrids and hybrids of domestic breeding companies. Statistically significant difference was found in ethanol yield by sites (P, Cilj istraživanja bio je utvrditi razliku u proizvodnji zrna i etanola iz kukuruza između domaćih hibrida kukuruza koji se uobičajeno koriste za proizvodnju zrna i uvezenih HTF (High Total Fermentable) deklariranih hibrida za proizvodnju etanola. Poljski pokus je postavljen na 3 lokacije (Osijek, Beli Manastir, Zagreb) dvije godine uzastopno (2012, 2013) u tri gustoće sklopa (60,000, 70,000 i 80,000 biljaka/ha). Hibridi tvrtke Pioneer, deklarirani kao “HTF” hibridi za proizvodnju etanola iz zrna kukuruza korišteni su kao kontrola za procjenu produktivnosti etanola iz domaćih hibrida Poljoprivrednog instituta Osijek i Bc Instituta d.d. Laboratorijska proizvodnja etanola utvrđena je Lemuz metodom. Sukladno ANOVA statističkoj analizi nisu utvrđene statistički značajne razlike u prinosu zrna i etanola između HTF hibrida i hibrida domaćih oplemenjivačkih kuća. Statistički značajna razlika utvrđena je u prinosu etanola po lokalitetima (P

Lignocellulosic residue has been demonstrated to be a carbon-neutral and sustainable resource that can provide a wide range of biobased fuels, chemicals and materials. In this study, central composite-based response surface methodology (RSM) was used to optimize process condition in acid-catalyzed pretreatment of pineapple leaves under the liquid hot water (LHW) technique. The experiment was conducted with consideration of the influencing parameters (type of acid catalyst, concentration, reaction temperature, and residence time). After pretreatment, the enzymatic hydrolysis of solid residue performance was evaluated to find the optimal pretreatment conditions based on the maximized glucose yield. The RSM method could estimate a maximum glucose yield of 91%, which could be obtained at a sulfuric acid concentration of 0.61 M and a temperature of 143.2 °C for 38.4 min. The results also showed valuable sugars with a low level of byproducts detected in the soluble phase during LHW pretreatment. Further study for bioethanol production found that the fermentation process gave the highest theoretical ethanol yield of 94.68% at 5% solid loading. However, a high solid loading (15%) could improve the performance in terms of productivity with 0.63 g/L-h. The pretreated pineapple leaves also involved the analysis of physiochemical characteristics. These properties clearly showed the destruction of hemicellulose and lignin, resulting in increased enzyme digestibility and further improvement of fermentability for ethanol production. The results of the present study showed that an acid-catalyzed LHW pretreatment could be effectively applied for the utilization of pineapple leaves in derived bioproduction.

With the consumption of energy and the spread of COVID-19, the demand for ethanol production is increasing in the world. The industrial ethanol fermentation microbes cannot metabolize the alginate component of macro algae, which affects the ethanol yield. In this research, the ethanol production process from macro algae by an alginate fermentation yeast Meyerozyma guilliermondii, especially the pretreatment process of Colpomenia sinuosa, was studied. At the same time, the experimental design of Box-Behnken was carried out to achieve the optimum fermentation performance. The concentration of KH2PO4 (A: 2–6 g.L−1), pH (B: 4–7), reaction time (C: 60–120 h) and temperature (D: 24–34 °C) were variable input parameters. During the ethanol production process, the algae powder was firstly mixed with water at 90 °C for 0.5 h. Later the fermentation culture medium was prepared and then it was fermented by the yeast Meyerozyma guilliermondii to produce ethanol. And the optimal fermentation parameters were as follows: fermentation temperature of 28 °C, KH2PO4 dosage of 4.7 g.L−1, initial pH of 6, and fermentation time of 99 h. The ethanol yield reached 0.268 g.g−1 (ethanol to algae), close to the predicted value of model. The generation of alginate lyase during the fermentation of algae was also examined. The highest alginate lyase activity reached 46.42 U.mL−1.

Made available in DSpace on 2022-04-29T08:31:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) There is a growing need of sustainable solutions for balancing agricultural production with the reduction of its environmental impacts. The rapid increase in sugarcane cultivation and the progressive conversion of pre-harvest burning (BH) to green harvest (GH) have brought into debate the contribution of agricultural sector to the greenhouse gas (GHG) mitigation. This study focused on the estimated GHG emission from sugarcane cultivation during years in which sugarcane areas in southern Brazil expanded and passed throughout an important transition, from 2006 to 2012, when harvest adopted was changed from burned to not-burned based. Sugarcane management and harvest were mapped through visual interpretation of Landsat-type satellite images, and the areas under sugarcane cultivation were distinguished according to each agricultural phase and harvest regime (i.e., manual harvest with burning vs. green mechanized harvest). Based on a broad data review and applying the IPCC (2006) methodologies, the results were expressed in terms of kilograms of carbon dioxide equivalent (kg CO2eq ha−1). Avoiding burn prior to harvest, even during expansion of sugarcane areas, promoted a mean reduction of GHG emission from 901 to 686 kg CO2eq ha−1 relative to harvest phase (24% lower) and an increase from 1418.3 to 1507.9 kg CO2eq ha−1 related to the ratoon maintenance phase (6% higher). Analyzing the total GHG emission per unit of cultivated sugarcane area (hectare), it was observed a decrease from 2275 to 2034 kg CO2eq ha−1 (11% reduction). The gradual transition of pre-harvest burning on that period has contributed to the reduction of GHG emission associated with sugarcane production being an important step towards GHG mitigation while still providing more sustainable sugar and ethanol production in southern Brazil. Department of Engineering and Exact Sciences College of Agricultural and Veterinarian Sciences São Paulo State University (FCAV/UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal Brazilian Biorenewables National Laboratory (LNBR) Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro, 10000, 13083-100, Campinas Federal University of São Carlos (UFSCar), Rodovia Anhanguera, Km 174 - Zona Rural, 13604-900, Araras Agrosatelite Applied Geotechnology, Rodovia SC 401, Km 5, No. 4850 Department of Engineering and Exact Sciences College of Agricultural and Veterinarian Sciences São Paulo State University (FCAV/UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal FAPESP: process 2011/16932-4

The electrochemical reduction of carbon dioxide (CO2) to chemicals is gaining great attention as a pragmatic solution for greenhouse gas mitigation and for the utilization of CO2 to produce useful fuels and chemical feedstocks using intermittent renewable energy sources. In recent years, strategies to design electrocatalysts for CO2 reduction to ethanol, a valuable liquid fuel, have been increasingly reported. The mechanistic understanding providing insights into steps of the reduction process has allowed for further development of highly efficient and selective catalysts. Several significant breakthroughs have been made; however, the door toward industrial-scale production of ethanol from CO2 is still wide open as most electrocatalytic systems reported so far are still suffering from low energy efficiency, inferior stability, and discouraging selectivity. Inspired by recent advances in the field, we herein provide a review of fundamental and material advances of the electrochemical CO2 reduction to ethanol. First, we discuss the pathways and the effects of reaction-environment factors on the formation of ethanol from both theoretical and spectroscopic points of view. We then give an overview of different strategies to design electrocatalysts for this reaction. Finally, we discuss the remaining challenges and propose promising future research directions, with the aim to bring this technology closer to practical applications.

The discovery of oxide-derived copper catalysts for CO2 electroreduction is an outstanding advance in the field of electrocatalysis. Their low overpotentials and improved selectivity towards C2 products make them unique. However, the structure of the active sites responsible for these improvements remains unclear. Herein, by means of a computational model including thermodynamic, kinetic, solvent and cation effects, we outline the atomic structure of the active sites responsible for ethanol evolution in OD-Cu catalysts. We also point out the specific features that determine selectivity and pinpoint the design criteria that should be fulfilled to enhance the catalysts’ selectivity toward ethanol. Specifically, we propose that square, four-atom Cu islands are the active sites of OD-Cu for CORR to ethanol, as they display favorable *CO dimerization and ethanol selectivity by virtue of their square, undercoordinated structure. This work has been supported by Spanish MICIUN’s RTI2018-095460-B-I00 and Marı́a de Maeztu MDM-2017-0767 grants and, in part, by Generalitat de Catalunya 2017SGR13 grant and by COST Action 18234, supported by the COST (the European Cooperation in Science and Technology). F.C.-V. thanks the Spanish MICIUN for a Ramón y Cajal research contract (RYC-2015-18996), and F.I. acknowledges additional support from the 2015 ICREA Academia Award for Excellence in University Research. O.P. thanks the Spanish MICIUN for an FPI PhD grant (PRE2018-083811). F.V. thanks the Spanish MICIUN for a Ramón y Cajal research contract (RYC-2012-10129). We are thankful to Red Española de Supercomputación (RES) for supercomputing time at SCAYLE (projects QS-2019-3-0018, QS-2019-2-0023, and QCM-2019-1-0034). The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences. F.C.-V. thanks Dr. Ioannis Katsounaros for insightful discussions. Patricia Verdugo is gratefully acknowledged for her help with the design of the table of contents figure.

The design of catalysts with controlled selectivity at will, also known as catalytic plasticity, is a very attractive approach for the recycling of carbon dioxide (CO2). In this work, we study how catalytically active hydroxyapatite (HAp) and brushite (Bru) interact synergistically, allowing the production of formic acid or acetic acid depending on the HAp/Bru ratio in the catalyst. Raman, wide angle X-ray scattering, X-ray photoelectron spectroscopy, scanning electron microscopy and electrochemical impedance spectroscopy studies, combined with an exhaustive revision of the crystalline structure of the catalyst at the atomic level, allowed to discern how the Bru phase can be generated and stabilized at high temperatures. Results clearly indicate that the presence of OH– groups to maintain the crystalline structural integrity in conjunction with Ca2+ ions less bonded to the lattice fixate carbon into C1, C2 and C3 molecules from CO2 and allow the evolution from formic to acetic acid and acetone. In this way, the plasticity of the HAp-Bru system is demonstrated, representing a promising green alternative to the conventional metal-based electrocatalysts used for CO2 fixation. Thus, the fact that no electric voltage is necessary for the CO2 reduction has a very favorable impact in the final energetic net balance of the carbon fixation reaction.

Background Low-cost raw materials such as lignocellulosic materials have been utilized in second-generation ethanol production process. However, the sequential and slow conversion of xylose into target products remains one of the main challenges for realizing efficient industrial lignocellulosic biorefinery. Results By applying different constant potentials to different microbial electrolysis cells with xylose as the sole carbon source, we analyzed the output of metabolites, microbial community structures, electron flow, and carbon flow in the process of xylose electro-fermentation by domesticated activated sludge. The bioreactors produced currents when applying positive potentials. The peak currents of the + 0.242 V, + 0.542 V and + 0.842 V reactors were 0.96 × 10–6 A, 3.36 × 10–6 A and 6.43 × 10–6 A, respectively. The application of potentials promoted the xylose consumption, and the maximum consumption rate in the + 0.542 V reactor was 95.5%, which was 34.8 times that of the reactor without applied potential. The potential application also promoted the production of ethanol and acetate. The maximum ethanol yield (0.652 mol mol−1 xylose) was obtained in the + 0.842 V reactor. The maximum acetate concentration (1,874 µmol L−1) was observed in the + 0.842 V reactor. The optimal potential for ethanol production was + 0.842 V with the maximum ethanol yield and energy saving. The application of positive potential caused the microorganisms to carry out ethanol fermentation, and the application of negative potential forced the microorganisms to carry out acetic fermentation. The potential application changed the diversity and community structure of microorganisms in the reactors, and the two most significantly changed families were Paenibacillaceae and Bacillaceae. Conclusion The constructed microbial electrolysis cells with different potentials obtained better production yield and selectivity compared with the reactor without applied potential. Our work provides strategies for the subsequent fermentation processes with different needs.

The fourth generation of bioethanol production is on a lookout for non-lignocellulosic biomass waste. One such candidate is chitin, the second most abundant biopolymer on earth. However, the crystalline nature of chitin hinders its application potential for bioethanol production. This limitation can be circumvented by hydrolysing this polymer into oligomers using chitinases. We used this hypothesis and isolated a Bacillus haynesii, a marine bacterium that utilizes colloidal chitin as a substrate and produces chitin oligosaccharides. Further, we utilized Mucor circinelloides to produce bioethanol using the chitin oligosaccharides in the shake flask. We investigated the effect of inoculum age, filling volume, different substrates, and substrate concentration on bioethanol production using Mucor circinelloides from Bacillus haynesii-produced chitin oligosaccharides. Bacillus haynesii demonstrated a maximum chitinase activity of 3.08 U/mL with specific activity of 96 U/mg at the 90th h. Chitin oligosaccharides produced by Bacillus haynesii were confirmed using mass spectrometry. Bioethanol concentration was determined using dichromate oxidation assay as well as gas chromatography. The research resulted in 7.4 g/L of ethanol from 30 g/L of chitin oligosaccharides, with a maximum ethanol yield of 0.25 g of ethanol/g substrate at the 55th h with 48 h inoculum in 80 mL of fermentation medium. Results suggest that chitin oligosaccharides from Bacillus haynesii are an effective and renewable substrate for bioethanol production.

Highlights • The ethanol yield increased by 34.87% after optimal ultrasonic irradiation. • Transcriptomics and metabolomics together revealed high yield mechanisms of ethanol. • Sonication treatment changed the expression of coding gene of ethanol synthetase. • Ultrasonic irradiation decreased the expression of organic acid in yeast., This study reports an enhancement of ethanol yield in Saccharomyces cerevisiae with low-intensity ultrasonic irradiation using fixed mode frequency generated by a self-developed six-frequencies (20, 23, 25, 28, 33, 40 kHz) ultrasonic device in our group. After sonication treatment, the ethanol production potential was determined. Under the optimal conditions of ultrasonic treatment (ultrasonic frequency 28 kHz, power density 180 W/L, and treatment time 24 h), the maximum ethanol yield increased by 34.87% compared to the control. Transcriptome sequencing showed that the ultrasonic treatment had expressional regulations on genes involved in pyruvate metabolism, glycolysis, pentose phosphate pathway, glucose transport, and reducing power production. The quantitative real-time polymerase chain reaction (qRT-PCR) further confirmed the changes in gene expression (up- or down-regulation). Metabolomics revealed that ultrasonic treatments increased intracellular glucose and nicotinamide adenine dinucleotide (NADH) contents, which are key metabolites for ethanol synthesis. Besides, ultrasonic treatments decreased the acetate and its derivatives resulting in lowered reverse consumption of pyruvate and thus promoted ethanol synthesis. These changes in gene expression and metabolites content might be the main reason why the ethanol yield in Saccharomyces cerevisiae increased after ultrasonic irradiation.

The search for a balance between the energy-related challenges of the future and providing nutritional security has resulted in the development of a market for biofuels of successive generations. The larger their portion in biofuel production, the less the prices of agricultural products will increase. The use of algae, cyanobacteria and aquatic plants in the production of liquid fuels is an alternative. The aim of this study was to determine the effect of thermal hydrolysis on degradation of polysaccharides contained in biomass of cyanobacteria Arthrospira platensis and to assess the effectiveness of ethanol production from preconditioned biomass. The study is aimed at the selection of the most advantageous parameters of thermochemical hydrolysis to reach the experiment variant with the best effects, degree of polysaccharide degradation and effectiveness of alcohol fermentation. The experiment was divided into two stages; in stage I, the possibility of obtaining fermentable sugars by hydrothermal and chemical treatment of the substrate was tested. Stage II involved an assessment of the effectiveness of the pretreatment methods to produce bioethanol in alcohol fermentation. Yeast used in industrial ethanol production—Saccharomyces cerevisiae As4—was used in the alcohol fermentation. The results have shown that the temperature of 150 °C was the most beneficial for the process of thermohydrolysis, and the mash in the microwave-heated sample contained the highest concentration of alcohol (0.97 g/l), which is 98% more than in the control mash and 37% more than in the conventionally heated sample.

This study evaluated the effects of three chemical pretreatments of biomass sorghum (BS): dilute alkaline (PTA1 and PTA2), dilute acid (PTB1 and PTB2) and alkaline hydrogen peroxide (PTC1 and PTC2) in the enzymatic hydrolysis and ethanol production. Among the six investigated conditions, the pretreatment with 7.36% H2O2 (PTC2) was the most efficient in the lignin removal and preservation of the polysaccharide fraction. After the enzymatic hydrolysis, increases in the glucose and xylose concentrations were observed in the pretreated BS hydrolysates, mainly in PTB1 and PTC1. All the hydrolysates obtained low concentrations of inhibitors. In the alcoholic fermentations with Pichia stiptis, the greatest ethanol yield was obtained in PTB1 hydrolysate (3.84 g L-1), corresponding to 16.15% of yield. The highest ethanol yield in PTB1 hydrolysate can be justified by the maximum concentration of xylose obtained in this hydrolysate, demonstrating the potential of P. stiptis in the fermentation of pentose to ethanol. The results indicated that biomass sorghum is an alternative lignocellulose source with potential for the production of second generation ethanol, opening up prospects for additional studies.

Orientador: Gonçalo Amarante Guimarães Pereira Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos Resumo: O Brasil é uma das principais potências no campo da produção de biocombustíveis com o bioetanol como seu principal produto. O bioetanol brasileiro é produzido principalmente pela fermentação da cana-de-açúcar e é conhecido como etanol de primeira geração (1G). Recentemente, materiais lignocelulósicos também estão sendo usados como matéria-prima, originando o etanol de segunda geração (2G). O bioetanol é considerado um produto de baixo valor agregado, portanto, baixos custos de produção são essenciais para que seja economicamente viável. Considerando os processos 1G e 2G, várias etapas e condições ainda podem ser aprimoradas. Na produção de etanol 1G, por exemplo, muitas vezes é detectada a presença de micro-organismos indesejáveis que levam a perdas severas e, em alguns casos, ao fechamento temporário da usina. Atualmente, a principal estratégia adotada para superar esse problema é o uso profilático de antibióticos. No entanto, a crescente preocupação relacionada à seleção de bactérias resistentes, juntamente com as questões ambientais e seu elevado custo, levaram a uma busca por agentes anti-microbianos alternativos. Na produção de etanol 2G, um dos principais desafios é a eficiente fermentação da xilose pela levedura S. cerevisiae. A xilose isomerase (XI) é uma enzima chave para conversão da biomassa lignocelulósica em etanol. No entanto, a maioria dos genes XI não são funcionais quando expressos em S. cerevisiae. No trabalho apresentado, os problemas que ocorrem na 1G e 2G são abordados. O Capítulo I tem como objetivo demonstrar que a XI de Propionibacterium acidipropionici se torna funcional em S. cerevisiae quando co-expressa com um complexo bacteriano de chaperoninas adquirindo uma capacidade elevada de converter xilose em etanol. No capítulo II é proposto um desenvolvimento de leveduras geneticamente modificadas capazes de controlar o crescimento bacteriano em fermentações etanólicas Abstract: Brazil is one of the main potencies in the field of biofuels production with bioethanol as its major product. Brazilian bioethanol is mostly produced by fermentation of sugarcane and is known as first-generation ethanol (1G). Recently, lignocellulosic materials are also being used as a feedstock, originating the second-generation ethanol (2G). Bioethanol is considered a low value-added product, therefore low production costs are essential for it to be economically viable. Considering 1G and 2G processes, several steps and conditions can still be improved. In 1G ethanol production for instance it is often detected the presence of unwanted microorganisms that lead to severe losses and in some cases temporary closure of the ethanol plant. Currently, the main strategy adopted to overcome this problem is the prophylactic use of antibiotics. Nevertheless, the crescent concern related to selection of resistant strains of bacteria, along with environmental issues and its elevated cost, have led to a search for alternative antimicrobial agents. In 2G ethanol production, one of the main challenges is efficient xylose fermentation by the yeast S. cerevisiae. Xylose isomerase (XI) is a key enzyme 2G biomass conversion. However, most XI genes are not functional when expressed in S. cerevisiae. In the presented work both 1G and 2G problems are addressed. Chapter I aims to demonstrate that XI from Propionibacterium acidipropionici becomes functional in S. cerevisiae when co-expressed with a bacterial chaperonin complex and has an elevated ability of converting xylose to ethanol. In chapter II is proposed a development of genetically modified yeast capable of controlling the bacterial growth in ethanolic fermentations Doutorado Bioenergia Doutora em Ciências CAPES

Corn is a valuable agricultural commodity in the United States and in the world. The causal agent of Stewart's wilt disease in corn, Pantoea stewartii subsp. stewartii, is a bacterial phytopathogen that is vectored into the plant by the corn flea beetle, Chaetocnema pulicaria. After entering the apoplast of the leaf, the bacteria cause water soaking symptoms before traveling to the plant xylem to form a dense biofilm, thereby blocking water transport and inducing necrosis and wilt. This results in reduced crop yield and may even lead to death of the corn plant. To better understand the in planta requirements of this pathogen, a whole transcriptome study was performed via RNA-Seq to determine genes differentially expressed in the bacteria while inside the corn. It was found that nutrient transporters and stress response genes were upregulated specifically when the bacteria are in their host plant, suggesting a response to nutrient availability and host defense in the xylem. Further elucidation of the genes required for the P. stewartii in planta lifestyle was performed via a reverse genetics approach where in-frame gene deletions and the corresponding complementation strains were constructed for genes that had shown a fitness defect in corn based on a previously published Tn-Seq study: genes encoding seven transcription factors, nsrR, iscR, lrp, nac, DSJ_00125, DSJ_03645, and DSJ_18135, as well as a hypothetical protein DSJ_21690. Investigation of the physiological role of these genes was performed using in planta virulence and competition assays for all strains. An in planta qRT-PCR analysis of bacterial gene transcription was also completed for the strains with deletions in nsrR and iscR. In vitro assays were performed on all strains to determine their capsule production and motility phenotypes. Taken together, it was seen that iscR is important for colonization capabilities in planta, both NsrR and IscR act as regulators, and lrp is important for full disease capabilities, perhaps due to reduced capsule and motility phenotypes. These findings lay the groundwork for finding potential disease intervention strategies not only against P. stewartii, but also other xylem-dwelling bacterial phytopathogens. In addition to exploring ways to enhance crop yield, an additional research area was on repurposing a byproduct of corn ethanol production, syrup. It was hypothesized that this corn-based syrup could be utilized as a carbon source to grown bacteria. In turn, the resulting bacterial biomass could then be added as a fish feed supplement in aquaculture. Syrup was tested as a growth medium for individual soil bacterial isolates as well as a full mixed bacterial community consortium to determine which bacteria could grow most efficiently, both in rate and yield. It was found that the highest growth rate and yield was from Bacillus species, some of which may have probiotic benefits to fish. Ultimately, the collective outcomes from these projects in basic research about a bacterial corn pathogen and applied research about beneficial microbes grown on a corn-based substrate are expected to improve scientific endeavors as well as agricultural practices. Doctor of Philosophy Corn is a top agricultural commodity in the United States, as a food for human consumption, a primary nutrient source used in animal feed, and a substrate consumed during biofuel production. These various corn-based industries are impacted by bacteria in multiple ways; in some cases, bacteria may cause disease that reduces crop yield, but other bacteria serve beneficial roles that enhance health. This dissertation research describes studies about the bacterium that causes Stewart's wilt disease in corn, Panteoa stewartii subsp. stewartii. In an initial experiment, the genes that P. stewartii expresses at the highest levels when it grows inside the corn plant were identified. These genes were deduced to be important for the ability of the bacterium to live successfully in this environment. This work was followed up with a more specific approach that examined the role of certain genes that were predicted to be master regulators of the expression of other genes in the ability of the P. stewartii to colonize the plant and/or cause disease. By identifying key bacterial genes, disease intervention strategies to combat Stewart's wilt and other similar bacterial plant pathogen diseases might become possible. Protecting corn yields is important for ethanol production. The final study of this dissertation examined the ability of bacteria to grow on a byproduct of ethanol production called syrup. The goal was to then use the biomass of these beneficial microbes as a food source for animals being produced in aquaculture facilities. Among the species tested, the highest growth rate and yield was from Bacillus subtilis, a safe-to-eat bacterium that has known beneficial health properties when consumed by fish. Overall, the research studies that were completed for this dissertation have the potential to improve agricultural practices by decreasing corn disease leading to increased corn yield and developing new downstream corn-based animal feed products.

Objective The alphaproteobacterium Zymomonas mobilis is an efficient ethanol producer, and Z. mobilis-based biorefinery shows great potential for biofuel production. Serial co-cultivation is an emerging approach that promotes inter-species interactions which can improve or rewire the metabolic features in industrially useful microorganisms by inducing frequent mutations. We applied this method to assess if it improves or rewires the desirable physiological features of Z. mobilis, especially ethanol production. Results We performed serial co-culture of Z. mobilis with the baker’s yeast, Saccharomyces cerevisiae. We observed filamentation of Z. mobilis cells in the co-culture, indicating that the Z. mobilis cells were exposed to stress due to the presence of a competitor. After 50 times of serial transfers, we characterized the generated Z. mobilis strains, showing that long term co-culture did not drive significant changes in either the growth or profile of excreted metabolites in the generated strains. In line with this, whole genome sequencing of the generated Z. mobilis strains revealed only minor genetic variations from the parental strain. 50 generations of Z. mobilis monoculture did not induce morphological changes or any significant genetic variations. The result indicates that the method needs to be carefully optimized for Z. mobilis strain improvement. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Ethanol is among the largest fermentation product used worldwide, accounting for more than $$90\%$$ of all biofuel produced in the last decade. However current production methods of ethanol are unable to meet the requirements of increasing global demand, because of low yields on glucose sources. In this work, we present an in silico multi-objective optimization and analyses of eight genome-scale metabolic networks for the overproduction of ethanol within the engineered cell. We introduce MOME (multi-objective metabolic engineering) algorithm, that models both gene knockouts and enzymes up and down regulation using the Redirector framework. In a multi-step approach, MOME tackles the multi-objective optimization of biomass and ethanol production in the engineered strain; and performs genetic design and clustering analyses on the optimization results. We find in silico E. coli Pareto optimal strains with a knockout cost of 14 characterized by an ethanol production up to $$ 19.74 \, \hbox {mmol} \, \hbox {gDW}^{-1} \, \hbox {h}^{-1} $$ ( $$+\,832.88 \% $$ with respect to wild-type) and biomass production of $$0.02 \, \hbox {h}^{-1}$$ ( $$-\,98.06 \% $$ ). The analyses on E. coli highlighted a single knockout strategy producing $$16.49 \, \hbox {mmol} \, \hbox {gDW}^{-1} \, \hbox {h}^{-1} $$ ( $$+\,679.29 \%$$ ) ethanol, with biomass equals to $$0.23 \, \hbox {h}^{-1}$$ ( $$-\,77.45 \% $$ ). We also discuss results obtained by applying MOME to metabolic models of: (i) S. aureus; (ii) S. enterica; (iii) Y. pestis; (iv) S. cerevisiae; (v) C. reinhardtii; (vi) Y. lipolytica. We finally present a set of simulations in which constrains over essential genes and minimum allowable biomass were included. A bound over the maximum allowable biomass was also added, along with other settings representing rich media compositions. In the same conditions the maximum improvement in ethanol production is $$+\,195.24\%$$ .

Mango fruits (Mangifera indica L.) are highly perishable, causing postharvest losses and producing agroindustrial waste. In the present work, native yeasts were used to evaluate ethanol production in overripe mango pulp. The two isolated strains showed similar sequences in the 18S rDNA region corresponding to Kluyveromyces marxianus, being different to the data reported in the NCBI database. Values of up to 5% ethanol (w/v) were obtained at the end of fermentation, showing a productivity of 4g/l/day, a yield of up to 49% of ethanol and a process efficiency of 80%. These results represent a viable option for using the surplus production and all the fruits that have suffered mechanical injury that are not marketable and are considered as agroindustrial waste, thus achieving greater income and less postharvest losses. Las frutas de mango (Mangifera indica L.) son altamente perecederas, lo cual causa pérdidas poscosecha y produce desechos agroindustriales. En el presente trabajo, se utilizaron 2 levaduras nativas para evaluar la producción de etanol en pulpa de mango senescente. Las 2 cepas aisladas mostraron similitud en la región 18S ADNr, correspondiente a Kluyveromyces marxianus, la cual es diferente a lo reportado en la base de datos del NCBI. Se obtuvieron valores de hasta el 6% de etanol (v/v) al final de la fermentación, con una productividad de hasta 4g/l/día, un rendimiento de hasta 49% de etanol y una eficiencia en el proceso fermentativo del 80%. Esto representa una opción viable para utilizar excedentes de producción o frutos que han sufrido daño mecánico y no son comercializables, al lograr más ingresos y menos pérdida poscosecha.

Background: An effective single culture that have high glycerol consumption and hydrogen and ethanol co-production yield is still in demand. Local isolate glycerol consumer Escherichia coli SS1was found to produce lower hydrogen under optimized ethanol production condition. Molecular approach was proposed to improve hydrogen yield of E. coli SS1 while maintaining the ethanol yield, particularly at acidic condition. Hence, the effect of additional copy of native hydrogenase gene hycE and recombinant clostridial hydrogenase gene hydA on hydrogen production by E. coli SS1 at low pH was investigated. Results: The E. coli recombinant with additional copy of hycE and clostridial hydA were subjected to fermentation using 10 g/L (108.7 mmol/L) of glycerol at initial pH 5.8. The recombinant hycE and recombinant hydA showed 41% and 20% higher hydrogen yield compared to wild-type (0.46 ± 0.01 mol/mol glycerol), respectively. The ethanol yield of recombinant hycE (0.50 ± 0.02 mol/mol glycerol) was about 30% lower than wild-type SS1, whereas ethanol yield of recombinant hydA (0.68 ± 0.09 mol/mol glycerol) was comparable to wild-type SS1. Conclusions: Both hycE and hydA could improve hydrogen yield at initial pH 5.8. The recombinant hydA could retain ethanol yield in spite of high hydrogen yield, suggesting clostridial hydA had an advantage over hycE gene in hydrogen and ethanol co-production under acidic condition. This study could serve as a useful guidance for future development of effective strain co-producing hydrogen and ethanol co-production. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri",sans-serif; mso-bidi-font-family:"Times New Roman";}

The methylotrophic yeast Pichia pastoris (syn. Komagataella phaffii) is a successful host widely used in recombinant protein production. The widespread use of a methanol-regulated alcohol oxidase 1 (AOX1) promoter for recombinant protein production has directed studies particularly about methanol metabolism in this yeast. Although there is comprehensive knowledge about methanol metabolism, there are other mechanisms in P. pastoris that have not been investigated yet, such as ethanol metabolism. The gene responsible for the consumption of ethanol ADH2 (XM_002491337, known as ADH3) was identified and characterized in our previous study. In this study, the ADH genes (XM_002489969, XM_002491163, XM_002493969) in P. pastoris genome were investigated to determine their roles in ethanol production by gene disruption analysis. We report that the ADH900 (XM_002491163) is the main gene responsible for ethanol production in P. pastoris. The ADH2 gene, previously identified as the only gene responsible for ethanol consumption, also plays a minor role in ethanol production in the absence of the ADH900 gene. The investigation of the carbon source regulation mechanism has also revealed that the ADH2 gene exhibit similar expression behaviours with ADH900 on glucose, glycerol, and methanol, however, it is strongly induced by ethanol.

Plastic composited corn silk was developed as a biotic/abiotic carrier for Zymomonas mobilis biofilm formation for the purpose of ethanol production. Furthermore, we explored the use of rice straw hydrolysate as substrate in both multistage continuous culture and repeated batch processes and compared the ethanol production efficiency by two strains of Z. mobilis. Biofilm formed by bacterial strains Z. mobilis ZM4 and TISTR551 were detected, and its proficiencies were compared under various conditions by scanning electron microscopy (SEM) and crystal violet assays. The greatest biofilm formed by both strains was found on day five after the inoculation. Z. mobilis strain ZM4 grown in repeated batch biofilm reactors produced higher yields of ethanol than TISTR551 grown under the same conditions, while TISTR551 produced higher yields of ethanol in the multistage continuous process. The yields were highly maintained, with no significant differences (p < 0.05) among the three consecutive repeated batches. These experiments highlight exciting uses for agricultural byproducts in the production of ethanol using Z. mobilis biofilm reactors.

Yeasts are important microorganisms used for ethanol production; however, they are not equally efficient in the amount of ethanol production under different environmental conditions. It is, therefore, necessary to screen for elite strains to utilize them for commercial production of these commodities. In this study, yeasts were isolated from different Ethiopian traditional fermented alcoholic beverages (teji, tella, shamiata and areqe tinisis), milk and ergo, teff and maize dough, soil and compost, flowers, and fruits to evaluate their potential use for ethanol fermentation process. Isolates were screened for efficient ethanol production and the selected ones were identified using phenotypic and genetic characters using D1/D2 region of LSU rDNA sequence analysis. The yeast isolates were evaluated based on their growth and fermentation of different carbon sources. Response surface methodology (RSM) was applied to optimize temperature, pH and incubation time using central composite design (CCD) in Design-Expert 7.0.0. A total of 211 yeasts colonies were isolated of which 60% were ethanologenic yeasts (ethanol producers) and 40% were non-ethanol producers. The yeast population detected from various sources was in the range of 105CFU from traditional foods and beverages to that of 103CFU from fruits and soil samples. The data also showed that the number of colony types (diversity) did not correlate with population density. The highly fermentative isolates were taxonomically characterized into four genera, of which 65% of the isolates (ETP37, ETP50; ETP53, ETP89, ETP94) were categorized under Saccharomyces cerevisiae, and the remaining were Pichia fermentans ETP22, Kluyveromyces marxianus ETP87, and Candida humilis ETP122. The S. cerevisiae isolates produced ethanol (7.6-9.0 g/L) similar with K. marxianus ETP87 producing 7.97 g/L; comparable to the ethanol produced from commercial baker's yeast (8.43 g/L) from 20 g/L dextrose; whereas C. humilis ETP122 and P. fermentans ETP22 produced 5.37 g/L and 6.43 g/L ethanol, respectively. S. cerevisiae ETP53, K. marxianus ETP87, P. fermentans ETP22 and C. humilis ETP122 tolerated 10% extraneous ethanol but the percentage of ethanol tolerance considerably decreased upon 15%. S. cerevisiae ETP53 produced ethanol optimally at pH 5.0, 60 h, and 34oC. pH 4.8, temperature 36oC, and 65 h of time were optimal growth conditions of ethanol fermentation by K. marxianus ETP87. The ethanol fermentation conditions of P. fermentans ETP22 was similar to S. cerevisiae ETP53 though the ethanol titer of S. cerevisiae ETP53 was higher than P. fermentans ETP22. Therefore, S. cerevisiae ETP53, K. marxianus and P. fermentans ETP22 are good candidates for ethanol production., Highlights • Among 211 yeast isolates, 126 were able to ferment dextrose. • Saccharomyces cerevisiae, Pichia fermentans, Kluyveromyces marxianus, and Candida humilis were isolated from traditional alcoholic drinks, compost, ergo, and enjera dough, respectively. • Kluyveromyces marxianus ETP87 can be used to produce ethanol from whey. • Saccharomyces cerevisiae, Kluyveromyces marxianus and Pichia fermentans are good candidate for ethanol production.

In this study, the ability of hydrodynamic cavitation pretreatment (HC) to increase ethanol yields at dry mill corn ethanol plants was investigated at pilot scale. Experiments were conducted at four HC energy densities, with and without jet cooking pretreatment and at a range of alpha-amylase (AA) doses. Corn slurries treated with HC had reduced particle sizes and significantly higher soluble saccharides. After simultaneous saccharification and fermentation (SSF), ethanol yields were 2.6% greater than in uncavitated controls. Jet cooking alone decreased ethanol yield compared to cavitated and control treatments. HC combined with jet cooking resulted in ethanol yields similar to controls. At alpha-amylase dosages 60% lower than those used at commercial scale plants (0.40% w enzyme/w dry corn), there was only a slight, insignificant reduction in ethanol yield. The net energy yield of HC was 47 kWh in additional ethanol for each kWh used for HC. In conclusion, HC improved the solubilization of saccharides and ethanol yield from corn, and had a positive net energy yield, thereby improving the efficiency of dry mill corn ethanol production from both an economic and environmental standpoint.

We developed the intensive multiple sequential batch simultaneous saccharification and cultivation of the selected thermotolerant yeast strain for single-step ethanol production. The selection and high-cell-density inoculum production of thermotolerant yeast able to produce ethanol under the optimal conditions for single-step ethanol fermentation has become a necessity. In this study, the newly isolated Kluyveromyces marxianus SS106 could tolerate high temperatures (35&ndash, 45 &deg, C) and grow under a wide range of pH values (3.0&ndash, 5.5), which are the optimum conditions of raw cassava starch hydrolyzing enzyme used in single-step ethanol fermentation. The high-cell-density concentration of K. marxianus SS106 was produced by a single batch and an intensive multiple sequential batch process in a 5-L stirred tank bioreactor using the simultaneous saccharification and cultivation (SSC) method. The single SSC process yielded the yeast cell biomass at a concentration of 39.30 g/L with a productivity of 3.28 g/L/h and a specific growth rate of 0.49 h&minus, 1. However, the yeast cell density concentration was higher in the intensive multiple sequential batch SSC than in the single batch process. This process yielded yeast cell biomass at concentrations of 36.09&ndash, 45.82 g/L with productivities of 3.01&ndash, 3.82 g/L/h and specific growth rates of 0.29&ndash, 0.44 h&minus, 1 in the first six batch cycle. The results suggested that the intensive multiple sequential batch simultaneous saccharification and cultivation of K. marxianus SS106 would be a promising process for high-cell-density yeast production for use as the inoculum in single-step ethanol fermentation. Furthermore, we also experimented with single-step ethanol production from raw cassava starch by K. marxianus SS106 in a 5-L stirred tank fermenter. This produced ethanol at a concentration of 61.72 g/L with a productivity of 0.86 g/L/h.

วารสารวิชาการและวิจัย มทร.พระนคร สาขาวิทยาศาสตร์และเทคโนโลยี, 13, 1, 116-126

Современное состояние научно-технологического развития и инновационная деятельность российских предприятий вызывают острую необходимость ускоренной интеграции цифровых технологий в производство, что послужило предпосылкой к проведению настоящего исследования. Предложенный онтологический подход к формализации знаний предметной области спиртового производства обеспечивает информационную поддержку предоставления комплексного взгляда на предприятие., The current state of scientific and technological development and the innovation activity of Russian enterprises gives rise to the urgent need for accelerated integration of digital technologies into production, which was a prerequisite for conducting this research. The proposed ontological approach to the formalization of knowledge of the subject area of alcohol production provides information support for the provision of a comprehensive look at the enterprise

Побочным продуктом спиртового производства является барда, которая эффективно применяется как кормопродукт в сухом виде. Проводятся исследования по получению из барды пищевой добавки на основе клетчатки, обогащенной аминокислотами, витаминами и микроэлементами. Получены данные по применению этой добавки в хлебопечении, By product of ethanol production is grain stillage which is effectively applied as fodder in a dry form. Researches on receiving from grain stillage of nutritional supplement composed of the cellulose enriched with amino acids, vitamins and microelements are conducted. Data on use of this supplement in bread baking are obtained

Ethanol was produced from oil palm frond juice (OPFJ) by using Saccharomyces cerevisiae yeast cells. Experiments were operated in a batch mode by varying the oil palm age between 3-4, 4-7, 7-10, 10-20 and 20-25 years. Experimental results showed that OPFJ at 3-4 years gave the highest concentrations of glucose and ethanol as 31.26 and 11.50 g/l. Ethanol yield was 0.39 g-ethanol/g-glucose, which estimated as 76.47% of the theoretical yield (0.51 g-ethanol/g-glucose). Additionally, the Monod and modified Gompertz equations were used to describe the kinetics of substrate utilizationand product formation. The values of the kinetic parameters in Monod and modified Gompertz equations of OPFJ extracted from oil palm aged 3-4 years were evaluated: maximum specific growth rate ( μ max ) was 0.29 g/g-VSS.hr, saturation concentration ( K s ) 47.05 g/l, maximum ethanol concentration ( P m ) 11.50 g/l, maximum ethanol production rate ( r p,m ) 0.24 g./l.hr and lag phase 0.12 hr. Both models fitted well to the experimental data, which had the high regression coefficient values (R 2 >0.95).

There is a carbon sequestration benefit to the ethanol manufacturing process if the CO2 that is created in the fermentation process in an ethanol plant is geologically stored by an enhanced oil recovery (EOR) project. In order to recover one barrel of oil using CO2-EOR, an equal or greater amount of CO2 must be sequestered in order to recover the oil (∼1.0–2.5 tonnes of CO2 are stored for each tonne of CO2 emissions resulting from combustion of the recovered oil). The oil produced from a CO2-EOR sequestration project is therefore either carbon neutral or carbon negative if the CO2 is sourced from the fermentation emissions from an ethanol plant. The 40.3 million metric tonnes of CO2 fermentation emissions vented during the production of 53.4 million liters of ethanol per year in the U.S. could result in production of 40–100 million barrels of carbon negative oil annually. A carbon value chain (CVC) based on carbon credits could incentivize the construction of a CCS infrastructure in the United States that begins with the capture of corn ethanol CO2 fermentation emissions. Utilization of biofuel fermentation emissions worldwide in bio-CO2-EOR sequestration projects would help achieve global CO2 emission reduction goals.

The mining industry in the Zambian Copperbelt has polluted the environment with heavy metals, the effects of which are a source of concern to host communities. It is globally known that remediation of polluted mine environments is expensive, and can be as high as US$48 000 or more per hectare, depending on the severity of contamination, using traditional physical and chemical approaches. These methods also often leave significant liabilities for host communities. This paper reviews available opportunities for mining companies in the Zambian Copperbelt to use integrated phytomining and production of ethanol, and its co-products, to minimize the costs for remediating polluted mine environments. The benefits of using this approach are manifold and include additional income streams from extracted metals and ethanol, creation of additional jobs for mine host communities, assured livelihoods for mine host communities even beyond mine closure, reclaimed land for food production and other activities, and improved corporate image for mining companies.

Science & Technology Asia, 23, 1, 57-66

The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. Two hundred and thirty-four yeast isolates from Greater Mekong Subregion (GMS) countries, i.e., Thailand, The Lao People's Democratic Republic (Lao PDR) and Vietnam were obtained. Five thermotolerant yeasts, designated Saccharomyces cerevisiae KKU-VN8, KKU-VN20, and KKU-VN27, Pichia kudriavzevii KKU-TH33 and P. kudriavzevii KKU-TH43, demonstrated high temperature and ethanol tolerance levels up to 45 °C and 13% (v/v), respectively. All five strains produced higher ethanol concentrations and exhibited greater productivities and yields than the industrial strain S. cerevisiae TISTR5606 during high-temperature fermentation at 40 °C and 43 °C. S. cerevisiae KKU-VN8 demonstrated the best performance for ethanol production from glucose at 37 °C with an ethanol concentration of 72.69 g/L, a productivity of 1.59 g/L/h and a theoretical ethanol yield of 86.27%. The optimal conditions for ethanol production of S. cerevisiae KKU-VN8 from sweet sorghum juice (SSJ) at 40 °C were achieved using the Box–Behnken experimental design (BBD). The maximal ethanol concentration obtained during fermentation was 89.32 g/L, with a productivity of 2.48 g/L/h and a theoretical ethanol yield of 96.32%. Thus, the newly isolated thermotolerant S. cerevisiae KKU-VN8 exhibits a great potential for commercial-scale ethanol production in the future.

With the limited fossil fuel resources and aggravating energy crisis, coupled with the concern about the climate change caused by greenhouse gases, many people hope that renewable fuels will be developed as an alternative to fossil fuels, with special attention being paid to bioethanol.1,2 Compared to fossil fuels, biofuels emit less ozone, benzene, carbon dioxide and other harmful pollutants. For a long time, bioethanol has been raising world-wide attention and many researchers are searching for alternative biomass sources for the production of bioethanol, such as corn,4 wood,5 sugarcane6 switch grass,7 rice straw,8 corn straw9 and wheat straw.10 Today, about 30 % of the corn currently grown is used for ethanol production, and more corn is needed to meet the increasing demand for bioethanol.11 The higher amounts of corn turned to biofuel production could have devastating effects on food supply around the world and cause conflicts in the food vs. fuel dilemma. Ethanol production from lignocellulose is a promising alternative but the current technologies for lignocellulose fermentation have to overcome the cost of the complex processes needed to release simple sugars from recalcitrant polysaccharides.12 With limited land area, pretreatment technical difficulties and low conversion rate, much more needs to be done in bioethanol production from lignocellulose. And the increasing need for energy consumption is expected to continue as the world’s population is expected to increase. In order to meet the expected increasing demand for bioethanol, there is a need to find alternative biomass sources, particularly those that do not rely on using large amounts of agricultural land. Marine algae are attractive renewable energy resources due to their abundance, high photosynthetic efficiency and production rate. Algae contain a low concentration of lignin and sugars can be easily released by simple operations such as milling or crushing, so seaweeds are proposed as one of the most promising biomass materials for ethanol production.13 Marine algae are classified into three groups by their colors: green, brown, and red. Brown algae, as the second most abundant marine biomass, have several key features of an ideal feedstock for biofuel production. They do not require arable land, fertilizer, or fresh water, they are of The Isolation and Performance Studies of an Alginate Degrading and Ethanol Producing Strain

The fractionation of agroindustrial and forest residues is a premise of the biorefinery concept. Thus, the present study focuses on pretreatments (hydrothermal and alkaline) and detoxification processes in order to transform green coconut fiber (GCF) into cellulose-rich material, dye biosorbent, bioactive phenolic compounds, lignin and arabinoxylan. The adsorption onto Amberlite XAD-7HP resin allowed the best recovery of phenolic compounds from hydrothermal pretreatment liquor, which presented potent antioxidant activities such as inhibition of hydroxyl and superoxide radicals of 77.05% and 76.88%, respectively. Acid precipitation was effective to recover 41.23% of the initial lignin content from alkaline pretreatment liquor. The detoxified hydrothermal pretreatment liquor was used as an additional source of glucose, increasing the final concentration of ethanol by 79.6% in simultaneous saccharification and fermentation of delignified GCF. Using delignified GCF as biosorbent, made it possible to obtain a static adsorption capacity of 200 mg of methylene blue dye per gram of biosorbent and good recyclability in dynamic experiments. Therefore, the proposed methodology guarantees a practical way of manufacturing value-added products from lignocellulosic materials.

Three typical waste furniture boards (fiberboard, chipboard, and blockboard) were pretreated with phosphoric acid and hydrogen peroxide (PHP). The fractionation process of these feedstocks was attempted in order to harvest the cellulose-rich fraction for enzymatic hydrolysis and bioethanol conversion, further, lignin recovery was also considered in this process. The results indicated that 78.9&ndash, 91.2% of the cellulose was recovered in the cellulose-rich fraction. The decreased crystallinity, which promoted the water retention capacity and enzyme accessibility, contributed greatly to the excellent hydrolysis performance of the cellulose-rich fraction. Therefore, rather high cellulose&ndash, glucose conversions of 83.3&ndash, 98.0% were achieved by hydrolyzing the pretreated furniture boards, which allowed for harvesting 208&ndash, 241 g of glucose from 1.0 kg of feedstocks. Correspondingly, 8.1&ndash, 10.4 g/L of ethanol were obtained after 120 h of simultaneous saccharification and fermentation. The harvested lignin exhibited abundant carboxyl &ndash, OH groups (0.61&ndash, 0.67 mmol g&minus, 1). In addition, approximately 15&ndash, 26 g of harvested oligosaccharides were integrated during PHP pretreatment. It was shown that PHP pretreatment is feasible for these highly recalcitrant biomass board materials, which can diversify the bioproducts used in the integrated biorefinery concept.

A two step, included process producing ethanol from oil palm fronts (OPF) by two-stage simultaneous saccharification and Saccharomyces cerevisiae fermentation followed by anaerobic digestion of its effluent to produce methane was investigated. OPF was soaked in dilute sulfuric acid, hydrogen peroxide and water consequently pretreated by microwave for preparing of cellulose and followed by simultaneous saccharification and fermentation. The result indicated OPF soaking in water gave a maximal ethanol yield was 0.32 g-ethanol/g-glucose which was 62.75% of the ethanol theoretical yield (0.51g-ethanol/g-glucose). The effluent from the ethanol production process was used to produce methane with the yield of 514 ml CH4/g VS added. Therefore, soaking in water and microwave co-pretreatment could helpful due to its low toxicity and low corrosion compare to sulfuric acid and hydrogen peroxide which improves the efficiency of enzymatic hydrolysis. The maximum energy output of the process (745 kWh/ ton of OPF) was about 72% of the energy contributed by cellulose fraction, contained in the oil palm frond.

Lactobacillus vini was recently described as a contaminant in industrial ethanol fermentations and its co-occurrence with Dekkera bruxellensis was noted. We investigated the growth characteristics of L. vini in cocultivation together with either Saccharomyces cerevisiae or D. bruxellensis. Lower cell numbers of both the yeasts and L. vini as well as a decrease in ethanol and lactate formation in mixed batch cultures compared with pure cultures were noted. L. vini formed cell aggregates (flocs) in all cultivation media with different shapes in Man-Rogosa-Sharpe and yeast extract-peptone-dextrose media. Flocs' size and proportion of cells bound to flocs increased with increasing ethanol concentration. In coculture, formation of lactic acid bacteria-yeast cell aggregates consisting of a bacterial core with an outer layer of yeast cells was observed. L. vini-D. bruxellensis flocs had a bigger surface, due to cells protruding from the pseudomycelium. The involvement of mannose residues in the flocculation between L. vini and yeasts was tested. The presence of mannose induced deflocculation in a concentration-dependent manner. Less mannose was required for the deflocculation of D. bruxellensis as compared with S. cerevisiae.

Ethanol production from lignocellulosic raw materials will generate multiple streams, since only a certain fraction of the material can be converted into sugars and then fermented to ethanol. This requires a ‘poly-generation’ approach, where by-products also must have high value (e.g. lignin, sugars from hemicellulose). To reach the large scale required for profitability, it is proposed that the best way is to integrate the new processes with existing industries, preferably those that already operate biomass-to-materials or biomass-to-fuels plants. One of the largest industry branches in this respect is the pulp and paper industry. Production of second generation ethanol (or other products) via sugars from lignocellulosic materials includes a relatively costly pre-treatment of the raw material in order to separate the lignin from the cellulose. This separation of the wood components already takes place in the chemical pulp mill, and the long proven technology in pulp production known as soda cooking (pre-treatment under alkaline conditions) is further evaluated in this study. It can be directly integrated into the recovery of chemicals and energy in the pulp mill. The pre-treatment of the lignocellulosic material studied in this work is alkaline and sulphur-free, and results in a technically pure cellulose to be fed to the hydrolysis stage, which makes it different compared to most of the other processes that aim to produce ethanol from lignocelluloses. The process chain from enzymatic hydrolysis to ethanol is very similar to that being used today for grain ethanol.The aim of this study was to define the conditions in alkaline pre-treatment stage for the separation of wood to a carbohydrate fraction for hydrolysis and ethanol production, and to a lignin fraction for the production of lignin products. Aspen (Populus tremula) and pine (Pinus sylvestris) wood from Nordic mills were studied. The reference case was alkaline pre-treatment according to the well-known soda pulping technique. The pulps of alkaline pre-treated aspen could be enzymatically hydrolysed very efficiently and fermented to ethanol with high yields (82–88% ethanol yield from theoretical maximum). It should be possible to use raw material of lower quality and cost than wood from the pulp industry. However, it can then be important to be able to take out non-process elements (NPEs) that otherwise accumulate in the process. This can be done by introducing an acidic prehydolysis stage prior to the alkaline fractionation. The content of Mg and Mn ions in the wood was possible to reduce by 85–90% and Ba and Ca ions by 75–80%. Potassium was virtually completely removed during the acidic pre-treatment stage.

This study aims to assess water footprint of ethanol production from molasses in Kanchanaburi and Suphanburi Provinces of Thailand, based on the water footprint concept methodology.The water footprint of ethanol from molasses can be calculated into three parts: sugar cane, molasses, and ethanol production. The green, blue, and grey water footprints of ethanol production from molasses in the Kanchanaburi Province are 849.7, 209.6, and 45.0 (m3/ton), respectively, whereas those of ethanol in the Suphanburi Province are 708.3, 102.9, and 64.8 (m3/ton), respectively. Study results depend on several factors such as climate, soil, and planting date. These are related and effective to the size of water footprint. Especially, if schedule of planting and harvest date are different, which causes the volume of rainfall to be different; these affect the size of water footprints. A limitation of calculation of grey water footprint from crop process has been based on a consideration rate of nitrogen only. Both provinces in the study area have their respective amount of the grey water footprint of molasses, and ethanol production is zero. The wastewater in molasses and ethanol production have a very high temperature and BOD, whereas the grey water footprint in this study is zero because the wastewater may be stored in pond, or it may be reused in area of factory and does not have a direct discharge into the water system. However, there is a risk for soil and ground water pollution.

In the coming years, a range of technological solutions aimed at reducing CO 2 emissions should be developed. The objective of this paper is to study the technical feasibility of CO 2 recycling into ethanol using solid oxide electrolysis cells (SOEC) technology, simulate the whole process using Aspen Plus™ software and make an economic assessment and a carbon footprint. The results of the economic analysis demonstrated that the ethanol production plant can deliver ethanol at a cost of $1.1/kg, assuming an internal rate of return on investment of 8%. Main challenges for this process are improvement of ethanol synthesis reaction catalysts and the SOEC performance.

Abundant, low prices and a highly reduced nature make glycerol to be an ideal feedstock for the production of reduced biochemicals and biofuels. Escherichia coli has been paid much attention as the platform of microbial cell factories due to its high growth rate (giving higher metabolite production rate) and the capability of utilizing a wide range of carbon sources. However, one of the drawbacks of using E. coli as a platform is its mixed metabolite formation under anaerobic conditions. In the present study, it was shown that ethanol could be exclusively produced from glycerol by the wild type E. coli, while d-lactic acid could be exclusively produced from glucose by pflA.cra mutant, where the glucose uptake rate could be increased by this mutant as compared to the wild type strain. It was also shown that the growth rate is significantly reduced in pflA.cra mutant for the case of using glycerol as a carbon source due to redox imbalance. The metabolic regulation mechanisms behind the fermentation characteristic were clarified to some extent.

Bioethanol is becoming increasingly important in energy supply and economic development. However, the low yield of bioethanol and the insufficiency of high-efficient genetic manipulation approaches limit its application. In this study, a novel transcription activator-like effector nuclease (TALEN) vector containing the left and right arms of TALEN was electroporated into Saccharomyces cerevisiae strain As2.4 to sequence the alcohol dehydrogenase gene ADH2 and the hygromycin-resistant gene hyg. Western blot analysis using anti-FLAG monoclonal antibody proved the successful expression of TALE proteins in As2.4 strains. qPCR and sequencing demonstrated the accurate knockout of the 17 bp target gene with 80% efficiency. The TALEN vector and ADH2 PCR product were electroporated into ΔADH2 to complement the ADH2 gene (ADH2 (+) As2.4). LC-MS and GC were employed to detect ethanol yields in the native As2.4, ΔADH2 As2.4, and ADH2 (+) As2.4 strains. Results showed that ethanol production was improved by 52.4 ± 5.3% through the disruption of ADH2 in As2.4. The bioethanol yield of ADH2 (+) As2.4 was nearly the same as that of native As2.4. This study is the first to report on the disruption of a target gene in S. cerevisiae by employing Fast TALEN technology to improve bioethanol yield. This work provides a novel approach for the disruption of a target gene in S. cerevisiae with high efficiency and specificity, thereby promoting the improvement of bioethanol production in S. cerevisiae by metabolic engineering.

Background Development of more sustainable biofuel production processes is ongoing, and technology to run these processes at a high dry matter content, also called high-gravity conditions, is one option. This paper presents the results of a life cycle assessment (LCA) of such a technology currently in development for the production of bio-ethanol from spruce wood chips. Results The cradle-to-gate LCA used lab results from a set of 30 experiments (or process configurations) in which the main process variable was the detoxification strategy applied to the pretreated feedstock material. The results of the assessment show that a process configuration, in which washing of the pretreated slurry is the detoxification strategy, leads to the lowest environmental impact of the process. Enzyme production and use are the main contributors to the environmental impact in all process configurations, and strategies to significantly reduce this contribution are enzyme recycling and on-site enzyme production. Furthermore, a strong linear correlation between the ethanol yield of a configuration and its environmental impact is demonstrated, and the selected environmental impacts show a very strong cross-correlation (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r^2>0.9$$\end{document}r2>0.9 in all cases) which may be used to reduce the number of impact categories considered from four to one (in this case, global warming potential). Lastly, a comparison with results of an LCA of ethanol production under high-gravity conditions using wheat straw shows that the environmental performance does not significantly differ when using spruce wood chips. For this comparison, it is shown that eutrophication potential also needs to be considered due to the fertilizer use in wheat cultivation. Conclusions The LCA points out the environmental hotspots in the ethanol production process, and thus provides input to the further development of the high-gravity technology. Reducing the number of impact categories based only on cross-correlations should be done with caution. Knowledge of the analyzed system provides further input to the choice of impact categories. Electronic supplementary material The online version of this article (doi:10.1186/s13068-016-0468-3) contains supplementary material, which is available to authorized users.

By applying metabolic control analysis and inhibitor titration we determined the degree of control (flux control coefficient) of pyruvate:ferredoxin oxidoreductase (PFOR) and bifunctional aldehyde–alcohol dehydrogenase (ADHE) over the fluxes of fermentative glycolysis of Entamoeba histolytica subjected to aerobic conditions. The flux-control coefficients towards ethanol and acetate formation determined for PFOR titrated with diphenyleneiodonium were 0.07 and 0.09, whereas for ADHE titrated with disulfiram were 0.33 and −0.19, respectively. ADHE inhibition induced significant accumulation of glycolytic intermediates and lower ATP content. These results indicate that ADHE exerts significant flux-control on the carbon end-product formation of amoebas subjected to aerobic conditions.

Eucalyptus globulus woodchips were subjected to steam explosion under a variety of operational conditions in order to evaluate their effect on a subsequent enzymatic hydrolysis. Steam explosion enhanced the enzymatic hydrolysis of the solid fraction. The application of a laccase-mediator system (LMS) before the enzymatic hydrolysis increased the glucose yield from 24.7 to 27.1%, probably as a result of the detoxification of the substrate. However, when xylanase was used to boost the LMS treatment, the hydrolysis rates did not improve. In order to assess the total amount of sugars obtainable from E. globulus, the liquid fraction obtained from the steam explosion was subjected to hydrolysis too. The enzymatic hydrolysis of the liquid fraction was more efficient than the acid hydrolysis, breaking down 82.7% of the xylooligosaccharide backbone into its monomeric constituent, xylose. The overall yield was 210. g of sugars per kg of raw material. © 2012 Elsevier Ltd.

The development of a yeast that converts raw starch to ethanol in one step (called consolidated bioprocessing) could yield large cost reductions in the bioethanol industry. The aim of this study was to develop an efficient amylolytic Saccharomyces cerevisiae strain suitable for industrial bioethanol production. A native and codon-optimized variant of the Aspergillus awamori glucoamylase gene were expressed in the S. cerevisiae Y294 laboratory strain. Codon optimization resulted to be effective and the synthetic sequence sGAI was then δ-integrated into a S. cerevisiae strain with promising industrial fermentative traits. The mitotically stable recombinant strains showed high enzymatic capabilities both on soluble and raw starch (2425 and 1140 nkat/g dry cell weight, respectively). On raw corn starch, the engineered yeasts exhibited improved fermentative performance with an ethanol yield of 0.42 (g/g), corresponding to 75 % of the theoretical maximum yield.

Fusarium spp. are significantly important plant pathogens, and some of them are ethanol-producing strains. During infection and/or ethanol production, Fusarium requires a plenty of energy that is mainly provided by mitochondria. Here we report the first mitogenome from a selected Fusarium oxysporum strain mh2-2 that produces ethanol from glucose and xylose. The size of this mitogenome, 46 kb, is different from the size of any reported Fusarium mitogenome. Our results provide insight into the functions and evolution of mitochondrial genes and genomes.

During anoxia, cytoplasmic pH regulation is crucial. Mechanisms of pH regulation were studied in the coleoptile of rice exposed to anoxia and pH 3.5, resulting in H(+) influx. Germinating rice seedlings survived a combination of anoxia and exposure to pH 3.5 for at least 4 d, although development was retarded and net K(+) efflux was continuous. Further experiments used excised coleoptile tips (7-10 mm) in anoxia at pH 6.5 or 3.5, either without or with 0.2 mM NO(3)(-), which distinguished two processes involved in pH regulation. Net H(+) influx (μmol g(-1) fresh weight h(-1)) for coleoptiles with NO(3)(-) was ∼1.55 over the first 24 h, being about twice that in the absence of NO(3)(-), but then decreased to 0.5-0.9 as net NO(3)(-) uptake declined from ∼1.3 to 0.5, indicating reduced uptake via H(+)-NO(3)(-) symports. NO(3)(-) reduction presumably functioned as a biochemical pHstat. A second biochemical pHstat consisted of malate and succinate, and their concentrations decreased substantially with time after exposure to pH 3.5. In anoxic coleoptiles, K(+) balancing the organic anions was effluxed to the medium as organic anions declined, and this efflux rate was independent of NO(3)(-) supply. Thus, biochemical pHstats and reduced net H(+) influx across the plasma membrane are important features contributing to pH regulation in anoxia-tolerant rice coleoptiles at pH 3.5.

application/pdf, Kluyveromyces marxianus KD-15, called flex yeast, is a strain that is insensitive to catabolite repression and has the capacity to produce ethanol efficiently from a mixture of beet molasses and whey powder. When a fermentation test was conducted in 50 mL of a medium containing 200 mg mL-1 of sugar as sugar beet thick juice diluted with an arbitrary amount of crude whey, strain KD-15 produced over 99 mg mL-1 ethanol in all the media tested, and ethanol formation decreased in proportion to the volume of whey by K. marxianus NBRC 1963, the parental strain of KD-15, and Saccharomyces cerevisiae NBRC 0224, the reference strain for conventional ethanol production. Fermentation of thick juice diluted with whey alone by strain KD-15 at 30 °C initially proceeded slower than that at 33 °C to 37 °C but finally bore the highest level of ethanol. The maximum ethanol concentration obtained in 1.5 L of a medium using a 2-L fermentor was elevated by aeration of 15 to 50 mL min-1 and reduced by that in excess of 100 mL min-1. Under optimized conditions in 72 h, strain KD-15 converted all of the sugars derived from thick juice and whey to ethanol at 102 mg mL-1, corresponding to 92.9% of the theoretical yield.

Ethanol was produced from the hydrolysate collected as the water-soluble (WS) portion after hot-compressed water (HCW) treatment of Japanese beech. The process involved saccharification with β-xylosidase followed by isomerization with xylose isomerase and fermentation with Saccharomyces cerevisiae. Several process schemes were compared to investigate the effect of process integration of saccharification, isomerization, and fermentation. Higher ethanol yields were obtained for the processes that integrated isomerization and fermentation or saccharification and isomerization. Integration of isomerization and fermentation was effective in converting xylose into ethanol. Similarly, integration of saccharification and isomerization was effective in converting xylooligosaccharides into xylulose. It is presumed that the saccharification reaction toward xylose and the isomerization reaction toward xylulose were linked and therefore each reaction was enhanced.

Ethanol was produced from the hydrolysate collected as a water-soluble (WS) portion and a residue after hot-compressed water (HCW) treatment of Japanese beech with and without fractionation. Simultaneous saccharifi cation with β-xylosidase and isomerization with xylose isomerase followed by fermentation with Saccharomyces cerevisiae were applied to the WS portion; simultaneous saccharifi cation with cellulase and fermentation with S. cerevisiae was applied to the residue. Integration of the processes for the WS portion and the residue was investigated to improve the conversion effi ciency throughout the whole process. The ethanol yield in the integrated process without fractionation was comparable with that for the process with fractionation. Ethanol yields were improved for both of the processes by modifying the operation pattern in which cellulase was added prior to fermentation of the residue.