Ethanol Production Research Papers - Academia.edu (original) (raw)

Wine production is a very old finding and it is defined as an alcoholic beverage obtained from grape juice using yeast as a fermenting organism [1]. With the progress of biotechnology many changes were brought in traditional wine making procedures [2]. In the mid of 19th century application of immobilized enzymes was developed and this technique was introduced and applied in the field of analysis and industrial production of biomolecules [3]. In recent years, cell immobilization techniques have become increasingly important and are being successfully applied in industrial processes such as the production of alcohols (ethanol, butanol and isopropanol), organic acids (including malic, citric, lactic and gluconic acids), enzymes (cellulase, amylase, lipase and others) and biotransformation of steroids for hormone production, wastewater treatment, and food applications (beer and wine) [4]. Cell immobilization in alcoholic fermentation is a rapidly expanding research area because of its beneficial technical and economic advantages compared to the conventional free cell system [3,5]. The host for yeast immobilization for wine making is always biologically inert [6]. In alcoholic fermentations, many investigators proposed wide variety of supports for immobilization of yeast cells like alginate and other inorganic materials [7-9]. Various supports have been proposed for potential use in main or secondary fermentations of wine, including inorganic supports such as, mineral kissiris [10] and Ca-alumina [11] since they are abundant and are of low cost there is a possibility of unlimited reuse. But none of them fulfilled the food-grade properties. Foodgrade natural supports such as, delignified cellulose materials [12], gluten pellets [13] and also fruit pieces like apple and quince [14,15] were successfully used as immobilization supports for wine production. However, for industrial wine production, it is important to identify a suitable support for cell immobilization that is of food grade, readily available, cost-effective and which may contribute to an overall improvement in the sensory characteristics of the final wine product.

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- Electron Microscopy, Saccharomyces cerevisiae, Ethanol Production, Watermelon
- by Tim Grant
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- Environmental Engineering, Climate Change, Bioenergy, Life Cycle Assessment

The energy input and output of three energy crop chains in Europe has been reviewed. The three chains are: bio-oil production from rape, soybean, or sun ower; ethanol production from cereal and sugar beet; and the use of herbaceous lignocellulosics as raw ÿber biomass. The energy input measurements are taken from the literature in terms of the average, minimum, and maximum for current agricultural practice. The bio-oil and ethanol chains are well deÿned and use e cient and mature technology, while the herbaceous lignocellulosic chains is still under development. The yield of bioenergy is limited by land and it is not directly correlated with inputs level; for maximum gain the inputs must be minimized. There is considerable margin for improvement in many areas with low yields. While the study does not address social and economic issues, it is clear that many of the species considered are multifunctional, and the maximizing of the economic opportunity will depend also on the exploitation of co-and by-products. ?

- by Gianpietro Venturi
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- Engineering, Technology, Ethanol Production, Energy Balance

Aims: The present investigation deals with the development of thermotolerant mutant strain of yeast for studying enhanced productivity of ethanol from molasses in a fully controlled bioreactor. Methods and Results: The parental culture of Saccharomyces cerevisiae ATCC 26602 was mutated using UV treatment. A single thermotolerant mutant was isolated after extensive screening and optimization, and grown on molasses medium in liquid cultures. The mutant was 1AE45-fold improved than its wild parent with respect to ethanol productivity (7AE2 g l )1 h )1 ), product yield (0AE44 g ethanol g )1 substrate utilized) and specific ethanol yield (19AE0 g ethanol g )1 cells). The improved ethanol productivity was directly correlated with titres of intracellular and extracellular invertase activities. The mutant supported higher volumetric and product yield of ethanol, significantly (P £ 0AE05) higher than the parental and other strains. The mutated cultures produced 1AE8-and 2AE6-fold more extracellular and intracellular invertase productivity, respectively, than that produced by its wild parent at 40°C. Thermodynamic studies revealed that the cell system exerted protection against thermal inactivation during formation of products. Conclusions: A mutant derivative of Sacchromyces cerevisiae with improved productivity of ethanol and invertases has been obtained, which showed concomitant improvement in thermostability of endogenous metabolism for formation of both ethanol and invertases. Significance and Impact of the Study: The results of the present study are of commercial value as the mutant can be used for ethanol production in parts of Pakistan where the temperature may go up to 40°C in April. Ethanol product yield coefficient and volumetric productivity, revealed the hyper-productivity of ethanol from molasses at 40°C, which is not appropriate for wild organism.

- by Muhammad Ferhan
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- Thermodynamics, Kinetics, Multidisciplinary, Entropy

The production of lignocellulolytic enzymes by eleven basidiomycetes species isolated from two ecosystems of Georgia was investigated for the first time under submerged (SF) and solid-state fermentation (SSF) of lignocellulosic by-products. Notable intergeneric and intrageneric differences were revealed with regard to the extent of hydrolase and oxidase activity. Several fungi produced laccase along with hydrolases in parallel with growth during the trophophase, showing that the synthesis of this enzyme is not connected with secondary metabolism. The lignocellulosic substrate type had the greatest impact on enzyme secretion. Some of the substrates significantly stimulated lignocellulolytic enzyme synthesis without supplementation of the culture medium with specific inducers. Exceptionally high carboxymethyl cellulase (CMCase, 122 U ml -1 ) and xylanase (195 U ml -1 ) activities were revealed in SF of mandarin peelings by Pseudotremella gibbosa IBB 22 and of residue after ethanol production (REP) by Fomes fomentarius IBB 38, respectively. The SSF of REP by T. pubescens IBB 11 ensured the highest level of laccase activity (24,690 U l -1 ), whereas the SSF of wheat bran and SF of mandarin peels provided the highest manganese peroxidase activity (570-620 U l -1 ) of Trichaptum biforme IBB 117. Moreover, the variation of lignocellulosic growth substrate provides an opportunity to obtain enzyme preparations containing different ratios of individual enzymes.

- by Nino Tsiklauri and +1
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- Environmental Engineering, Chemical Engineering, Technology, Biological Sciences

A circulating loop bioreactor (CLB) with cells immobilized in loofa sponge was constructed for simultaneous aerobic and anaerobic processes. The CLB consists of an aerated riser and a non-aerated downcomer column connected at the top and bottom by cylindrical pipes. Ethanol production from raw cassava starch was investigated in the CLB. Aspergillus awamori IAM 2389 and Saccharomyces cerevisiae IR2 immobilized on loofa sponge were placed, respectively, in the aerated riser column and non-aerated downcomer column. Both aamylase and glucoamylase activities increased as the aeration rate was increased. Ethanol yield and productivity increased with an increase in the aeration rate up to 0.5 vvm, but decreased at higher aeration rates. The CLB was operated at an aeration rate of 0.5 vvm for more than 600 h, resulting in an average ethanol productivity and yield from raw cassava starch of 0.5 g-ethanol l-1 h-1 and 0.45 g ethanol/g starch, respectively. In order to increase ethanol productivity, it was necessary to increase the dissolved oxygen (DO) concentration in the riser column and decrease the DO concentration in the downcomer column. However, increasing the aeration rate resulted in increases in the DO concentration in both the riser and the downcomer columns. At high aeration rate, there was no significant difference in the DO concentration in the riser and downcomer columns. The aeration rate was therefore uncoupled from the liquid circulation by attaching a timecontrolled valve in the upper connecting pipe. By optimizing the time and frequency of valve opening, and operation at high aeration rate, it was possible to maintain a very high DO concentration in the riser column and a low DO concentration in the downcomer column. Under these conditions, ethanol productivity increased by more than 100%, to 1.17 g l-1 h-1 .

- by Noel Roble
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- Chemistry, Productivity, Starch, Medicine

Using standard laboratory equipment, thermochemically pretreated oat straw was enzymatically saccharified and fermented to ethanol, and after removal of ethanol the remaining material was subjected to biogas digestion. A detailed mass balance calculation shows that, for steam explosion pretreatment, this combined ethanol fermentation and biogas digestion converts 85-87% of the higher heating value (HHV) of holocellulose (cellulose and hemicellulose) in the oat straw into biofuel energy. The energy (HHV) yield of the produced ethanol and methane was 9.5-9.8 MJ/(kg dry oat straw), which is 28-34% higher than direct biogas digestion that yielded 7.3-7.4 MJ/(kg dry oat straw). The rate of biogas formation from the fermentation residues was also higher than from the corresponding pretreated but unfermented oat straw, indicating that the biogas digestion could be terminated after only 24 days. This suggests that the ethanol process acts as an additional pretreatment for the biogas process.

- by Volkmar Passoth and +3
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- Renewable Energy, Energy, Bioenergy, Biogas

A study of the comparative kinetics of standard S. uvarum ATCC 26602 with S. cerevisiae Y-10 (an isolate) and a highly flocculent strain of S. uvarum in batch mode has shown that both the isolate and the highly flocculent S. uvarum strain... more

- by Digambar Gokhale
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- Engineering, Technology, Kinetics, Biological Sciences

The objective of this work was to evaluate the feasibility of ethanol production by fermentation of coffee husks by Saccharomyces cerevisiae. Batch fermentation studies were performed employing whole and ground coffee husks, and aqueous extract from ground coffee husks. It was observed that fermentation yield decreased with an increase in yeast concentration. The best results were obtained for the following conditions: whole coffee husks, 3 g yeast/l substrate, temperature of 30°C. Under these conditions ethanol production was 8.49 ± 0.29 g/100 g dry basis (13.6 ± 0.5 g ethanol/l), a satisfactory value in comparison to literature data for other residues such as corn stalks, barley straw and hydrolyzed wheat stillage (5-11 g ethanol/l). Such results indicate that coffee husks present excellent potential for residue-based ethanol production.

- by Evelyn Oliveira
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- Engineering, Technology, Production, Coffee

Background, aim, and scope Algae biomass has great promise as a sustainable alternative to conventional transportation fuels. In this study, a well-to-pump life cycle assessment (LCA) was performed to investigate the overall sustainability and net energy balance of an algal biodiesel process. The goal of this LCA was to provide baseline information for the algae biodiesel process. Materials and methods The functional unit was 1,000 MJ of energy from algal biodiesel using existing technology. Systematic boundary identification was performed using relative mass, energy, and economic value method using a 5% cutoff value. Primary data for this study were obtained from The USLCI database and the Greenhouse Gases, Regulated Emissions and Energy use in Transportation model. Carbohydrates in coproducts from algae biodiesel production were assumed to displace corn as a feedstock for ethanol production.

- by Jashank Joshi
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- Environmental Engineering, Life Cycle Assessment, GHG Emissions, Natural Gas

Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production. Results The effects of biomass loading, hydrogen peroxide loading, residence time, and pH control were tested in combination with subsequent digestion with a commercial enzyme preparation, optimized mixtures of four commercial ...

- by Mike Cotta
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- Chemical Engineering, Bioinformatics, Chemistry, Biomass

Bioconversion of cereal straw to bioethanol is becoming an attractive alternative to conventional fuel ethanol production from grains. In this work, the best operational conditions for steam-explosion pretreatment of wheat straw for ethanol production by a simultaneous saccharification and fermentation process were studied, using diluted acid [H 2 SO 4 0.9 % (w/w)] and water as preimpregnation agents. Acid-or water-impregnated biomass was steam-exploded at different temperatures (160-200°C) and residence times (5, 10, and 20 min). Composition of solid and filtrate obtained after pretreatment, enzymatic digestibility and ethanol production of pretreated wheat straw at different experimental conditions was analyzed. The best pretreatment conditions to obtain high conversion yield to ethanol (approx 80% of theoretical) of cellulose-rich residue after steam-explosion were 190°C and 10 min or 200°C and 5 min, in acid-impregnated straw. However, 180°C for 10 min in acid-impregnated biomass provided the highest ethanol yield referred to raw material (140 L/t wheat straw), and sugars recovery yield in the filtrate (300 g/kg wheat straw).

Xylanase is an enzyme in high demand for various industrial applications, such as those in the biofuel and pulp and paper Welds. In this study, xylanase-producing microbes were isolated from the gut of the wood-feeding termite at 50°C. The isolated microbe produced thermostable xylanase that was active over a broad range of temperatures (40-90°C) and pH (3.5-9.5), with optimum activity (4,170 § 23.5 U mg ¡1 ) at 60°C and pH 4.5. The enzyme was puriWed using a strong cation exchanger and gel Wltration chromatography, revealing that the protein has a molecular mass of 205 kDa and calculated pI of 5.38. The half-life of xylanase was 6 h at 60°C and 2 h at 90°C. The isolated thermostable xylanase diVered from other xylanases reported to date in terms of size, structure, and mode of action. The novelty of this enzyme lies in its high speciWc activity and stability at broad ranges of temperature and pH. These properties suggest that this enzyme could be utilized in bioethanol production as well as in the paper and pulp industry.

- by Sachin Kashanwal
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- Biotechnology, Bioenergy, Industrial Biotechnology, Biofuels

Severe hypoxia exposure and exhaustive exercise in goldfish both elicit a strong activation of substrate-level phosphorylation with the majority of the metabolic perturbations occurring in the white muscle. Approximately half of the muscle glycogen breakdown observed during severe hypoxia exposure was accounted for by ethanol production and loss to the environment, which limited the extent of muscle glycogen recovery when animals were returned to normoxic conditions. Ethanol production in goldfish is not solely a response to anoxia/hypoxia exposure however, as a transient increase in ethanol production was observed during the early stages of recovery from exhaustive exercise. These data suggest that ethanol production is a ubiquitous "anaerobic" end product, which accumulates whenever metabolic demands exceed mitochondrial oxidative potential. Exhaustive exercise and hypoxia exposure both caused a 7 to 8 μmol g − 1 wet mass increase in muscle [lactate] and the rates of recovery following these perturbations were similar. The rates of muscle PCr and pHi recovery after hypoxia exposure and exhaustive exercise were similar with levels returning to controls values within 0.5 h. Surprisingly, liver [glycogen] was not depleted during exposure to severe hypoxia, however, during recovery from both hypoxia and exercise dramatically different responses in liver [glycogen] were noted. During the early stages of recovery, liver [glycogen] transiently increased to high levels after exhaustive exercise, while during recovery from hypoxia there was a transient decrease in liver glycogen over the same time frame. Overall, this points to the liver playing a dramatically different role in facilitating recovery from exercise compared with hypoxia exposure.

- by Milica Mandic and +1
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- Skeletal muscle biology, Energy Metabolism, Biological Sciences, Environmental Sciences

RESUMO: A conservação da cana-de-açúcar na forma de silagem vem se destacando nos últimos anos em razão dos benefícios na operacionalidade. No entanto, quando ensilada sem aditivos a cana apresenta fermentação alcoólica com perda no valor nutritivo, resultante da atividade de leveduras. Considerando a hipótese que o uso da cal na ensilagem da cana pode inibir o desenvol- vimento das

- by Eduardo da Cunha
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- Sugar cane, Ethanol Production, Calcium Hydroxide, Alcoholic Fermentation

Maximum ethanol productions of two enological yeast strains (Sacc.haromyces cerevisiae K1 and 738-2) were compared during alcoholic fermentation under conditions where substrate was not a limiting factor. Although strain 738-2 seemed to exhibit the lowest sensitivity to ethanol, the strain Ki showed a higher production of ethanol, and a higher CO 2 production rate in presence of ethanol than the strain 738-2.

- by Jean-michel Salmon
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- Engineering, Technology, Biological Sciences, Saccharomyces cerevisiae

This article argues that, except in California, environmental justice considerations have not received sufficient attention in climate change policy debates. It explores the environmental justice implications of emerging domestic climate change policies and provides policymakers with specific suggestions on how to integrate environmental justice concerns. The article begins by introducing the environmental justice movement and its central principles, and then

- by Alice Kaswan
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- Environmental Law, Climate Change, Climate change policy, Sustainable Development

A comparative study of cellulose crystallinity based on the sample crystallinity and the cellulose content in plant fibres was performed for samples of different origin. Strong acid hydrolysis was found superior to agricultural fibre analysis and comprehensive plant fibre analysis for a consistent determination of the cellulose content. Crystallinity determinations were based on X-ray powder diffraction methods using sideloaded samples in reflection (Bragg-Brentano) mode. Rietveld refinements based on the recently published crystal structure of cellulose Ib followed by integration of the crystalline and amorphous (background) parts were performed. This was shown to be straightforward to use and in many ways advantageous to traditional crystallinity determinations using the Segal or the Ruland -Vonk methods. The determined cellulose crystallinities were 90 -100 g/100 g cellulose in plant-based fibres and 60 -70 g/100 g cellulose in wood based fibres. These findings are significant in relation to strong fibre composites and bio-ethanol production.

- by Anders Thygesen and +2
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- Materials Engineering, Rietveld refinement, Cellulose, Crystal structure

This paper addresses the agroenergy as a response to the self-confrontation with development and modernity side effects, in a risk society context. Brazil stands out in this scenario with a consolidated production of ethanol, and a recent program that encourages the biodiesel production. We argue, however, that such forms of production do not generate, necessarily, positive effects on rural development, neither socio-economically, neither environmentally. Nevertheless, agrofuel production experiences arise, headed by family farmers, which can be considered as a self-confrontation to side effects of the traditional Brazilian agroenergy model, based on large and modern monocultures. Through two initiatives in Rio Grande do Sul, we demonstrate how the family farmers make agrofuels in an integrated way with food, strengthening their agency capacity in promoting and driving rural development processes more sustainable. Thus, agroenergy arises as an alternative to diversify the family far...

- by Alexandra Michaelsen
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- Engineering, Socioeconomics, Bioenergy, Biodiesel

Terpenoids are the largest group of small-molecule natural products, with more than 60,000 compounds made from isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). As the most diverse group of small-molecule natural products, terpenoids play an important role in the pharmaceutical, food, and cosmetic industries. For decades, Escherichia coli (E. coli) and Saccharomyces cerevisiae (S. cerevisiae) were extensively studied to biosynthesize terpenoids, because they are both fully amenable to genetic modifications and have vast molecular resources. On the other hand, our literature survey (20 years) revealed that terpenoids are naturally more widespread in Bacillales. In the mid-1990s, an inherent methylerythritol phosphate (MEP) pathway was discovered in Bacillus subtilis (B. subtilis). Since B. subtilis is a generally recognized as safe (GRAS) organism and has long been used for the industrial production of proteins, attempts to biosynthesize terpenoids in th...

- by Linda Dijkshoorn
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- Engineering, Chemical Engineering, Chemistry, Biomedical Engineering

An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation-depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q EtOH) but not the ethanol yields (Y EtOH) in Saccharomyces cerevisiae. Within the same phenol functional group (aldehyde, ketone, and acid) the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P). Many pentose-utilizing strains Escherichia coli, Pichia stipititis, and Zymomonas mobilis produce ethanol in concentrated hemicellulose liquors but detoxification by overliming is needed. Thermoanaerobacter mathranii A3M3 can grow on pentoses and produce ethanol in hydrolysate without any need for detoxification.

- by Anne-belinda Bjerre
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- Chemistry, Technology, Biomass, Medicine
- by George Ziobro
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- Engineering, Technology, Biological Sciences, Ethanol Production

Water hyacinth biomass is a potential substrate for the production of ethanol which can be conveniently used as a gasoline additive as an octane booster and improve the vehicle emissions. The present study is focused on isolating and screening indigenous fungi for the hydrolysis of water hyacinth in the lignocellulosic conversion process. The initial cellulose activity was measured as I CMC (carboxymethyl cellulose) index which was found to be max at pH=5. Crude enzymes extracted after solid state fermentation (SSF) in an effort to reduce the cost of ethanol production, which needs lesser infrastructure and relatively less skilled manpower besides being able to use cheaper raw materials for enzyme production. The cellulytic and xylanytic activity was monitored using water hyacinth as substrate. Out of several isolates screened, best result was recorded up to 131.995 mg/g of reducing sugar and xylose yield up to 210.4 mg/g of WHB. Concentrated enzymatic hydrolysate of WHB containing reducing sugars and xylose was used for ethanol fermentation. The maximal ethanol yield was 2.217 g/l using Pichia stipitis, 2.163 g/l using Candida shehatae and 1.925 g/l using Saccharomyces cerevisae. Fungal isolate F6 provided the best yield as well as total extracellular enzyme production in comparison to other fungal strains, so identification of the fungal sample to its nearest species was undertaken. Fungal strain F6 (Alternaria alternate) was sequenced and the genomic DNA information was submitted to gene bank NCBI and an unique accession no JQ781696 was assigned.

- by Anamica Bhattacharya
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- Bioengineering, Biotechnology, Ethanol Production, Water Hyacinth
- by Art Ragauskas
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- Genetics, Biomass, Bioenergy, Energy Conversion

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The aims of this study were to investigate the bioethanol production of thick juice as intermediate from sugar beet processing in batch culture by free Saccharomyces cerevisiae cells and the effect of sugar concentration on ethanol yield and CO 2 weight loss rate. Thick juice and molasses of sugar beet from a domestic sugar factory were diluted with distilled water to give a total sugar concentration of 5, 10, 15, 20 and 25% (w w À1). Initial concentration of fermentable sugars of 20% (w w À1) in culture medium can be taken as optimal, enabling maximal ethanol yield (68%) and maximal CO 2 evolution rate was realized, amounting to more than 90 g L À1 h À1. The optimal concentration of fermentable sugar from thick juice for bioethanol production by free S. cerevisiae cells was 20% (w w À1) at 30 C, pH 5 and agitation rate 200 rpm gave maximum ethanol concentration of 12% (v v À1).

- by Jovana Grahovac
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- Engineering, Technology, Production, Biomass

Ethanol production has increased in the past decade as a result of growth in the dry grind industry. In the dry grind process, the first step is grinding of corn. The particle size of the resulting ground corn can affect the fermentation process and the particle size of dried distillers' grains with solubles (DDGS), a coproduct of dry grind processing. Few data are available that characterize particle size distributions of ground corn or DDGS. The objective was to determine particle size distributions of ground corn and DDGS. Samples of ground corn and DDGS were obtained from nine dry grind plants; particle size distribution, geometric mean diameter (d gw ) and geometric standard deviation (S gw ) were determined. The d gw of ground corn and of DDGS were not different among processing plants. The overall mean d gw of ground corn was not different from that of DDGS. Most of the ground corn (80 g/100 g) and DDGS (70 g/100 g) were recovered in the three largest particle size categories. The particle size distributions of ground corn were not correlated (r < 0.35) to particle size distributions of DDGS.

- by Vijay Singh
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- Ethanol Production, Transactions, Particle Size, Particle Size Distribution

In this study, the ethanol production by the mesophilic fungus Neurospora crassa from BG was studied and optimized concerning the induction of lignocellulose degrading enzymes and the production phase as well. The production of cellulolytic and hemicellulolytic enzymes was studied under solid-state cultivation (SSC). SSC in a laboratory horizontal bioreactor using the optimized medium, WS and BG in the ratio 1:1 and initial moisture level 61.5%, allowed the large scale production of the multienzymatic system. Similar yields with those from flasks experiments, as high as 1073, 56, 4.2, 1.6, 3.1, 5.7 and 0.52 U g À1 carbon source of xylanase, endoglucanase, cellobiohydrolase, b-glucosidase, a-L-arabinofuranosidase, acetyl esterase and feruloyl esterase, respectively, were obtained. Chromogenic (fluorogenic) 4-methylumbelliferyl substrates were used to characterize the major activities of the multienzyme component, after the separation by isoelectric focusing (IEF) electrophoresis. Alkali pre-treated BG was used for ethanol production. A yield of about 74 g of ethanol kg À1 dry BG (5, 6 g L À1 ) was obtained under optimum conditions (aeration 0.1 vvm, pre-treatment with 1 g NaOH 10 g À1 dry BG).

- by Evangelos Topakas
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- Biomass, Multidisciplinary, Neurospora crassa, Saccharomyces cerevisiae
- by Peter Petracek
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- Metabolism, Carbon Dioxide, Packaging, Postharvest Physiology
- by oscar sanchez
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- Process Synthesis, Ethanol Production, Biotechnology and Bioprocessing

Purpose Lignocellulosic ethanol has received special research interest, driven by concerns over high fuel prices, security of energy supplies, global climate change as well as the search of opportunities for rural economic development. A well-to-wheel analysis was conducted for ethanol obtained from black locust (Robinia pseudoacacia L.) by means of the life cycle assessment (LCA) methodology. This study assesses the environmental profile of using ethanol in mixtures E10 and E85 as transport fuel in comparison with conventional gasoline (CG). In addition, the best model of black locust cultivation was analysed under an environmental point of view. Methods The standard framework of LCA from International Standards Organisation was followed. To compare the environmental profiles, the study addressed the impact potentials taking into account the distance travelled by vehicles with the fuel tank full of CG. The product system includes all the processes involved from the black locust cultivation to the final use of fuels in a vehicle. The transport of all the chemicals and products is also included in the system boundaries. Results According to the results, fuel ethanol derived from black locust biomass may help to reduce the contributions to global warming, acidification, eutrophication and fossil fuels use specifically due to the low input production regime of the agricultural stage. These reductions would be increased with the increasing ratio of ethanol in the blend. Moreover, the use of lignin, biogas and other solid waste as fuel to meet the energy requirements of the plant, positively contribute to the environmental profile of cellulosic ethanol. On the contrary, ethanol blends are less environment friendly that CG in terms of photochemical oxidants formation. The cultivation of black locust following a low-input production regime, without agrochemicals application and extra irrigation is an important reason for the environmental improvement. Conclusions Efforts should be made to promote the production of black locust according to principles of sustainable cultivation. Moreover, technological development in ethanol production could help to improve the environmental profile in the life cycle of ethanol-based fuels. It could be interesting to develop a strategic planning which allows identifying the potential regions not only in Italy but also in other European countries in order to increase the black locust biomass yield. The cultivation of short rotation forestry and/or short rotation coppices under low-input regimes presents potential environmental benefits and advantages for the future of secondgeneration ethanol production in Europe.

- by Gumersindo Feijoo and +2
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- Environmental Engineering, Strategic Planning, Life Cycle Assessment, Economic Development

The dilute acid hydrolysis of grass and cellulose with phosphoric acid was undertaken in a microwave reactor system. The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemi-cellulose hydrolysis, due to a rapid hydrolysis reaction at moderate temperatures. The optimum conditions for grass hydrolysis were found to be 2.5% phosphoric acid at a temperature of 1758C. It was found that sugar degradation occurred at acid concentrations greater than 2.5% (v/v) and temperatures greater than 1758C. In a further series of experiments, the kinetics of dilute acid hydrolysis of cellulose was investigated varying phosphoric acid concentration and reaction temperatures. The experimental data indicate that the use of microwave technology can successfully facilitate dilute acid hydrolysis of cellulose allowing high yields of glucose in short reaction times. The optimum conditions gave a yield of 90% glucose. A pseudo-homogeneous consecutive first order reaction was assumed and the reaction rate constants were calculated as: k 1 ¼ 0.0813 s 21 ; k 2 ¼ 0.0075 s 21 , which compare favourably with reaction rate constants found in conventional non-microwave reaction systems. The kinetic analysis would indicate that the primary advantages of employing microwave heating were to: achieve a high rate constant at moderate temperatures: and to prevent 'hot spot' formation within the reactor, which would have cause localised degradation of glucose.

- by Mohammad Ahmad
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- Chemical Engineering, Kinetics, Bioenergy, Biofuels

- by Mohammad Ahmad
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- Chemical Engineering, Kinetics, Bioenergy, Biofuels
- by Giti Emtiazi and +2
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- Ethanol Production, Ethanol, Process biochemistry, Rice Straw
- by Mohammad Taherzadeh
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- Renewable Energy, Production, Biomass, Bioenergy

The growth inhibition of Moorella sp. HUC22-1 by undissociated acetic acid was analyzed using a non-competitive inhibition model coupled with a pH inhibition model. In the cells grown on H2 and CO2, the inhibition constant, K(p) of the undissociated acetic acid was 6.2 mM (164 mM as the total acetate at pH 6.2, pKa = 4.795, 55 degrees C), which was 1.5-fold higher than that obtained in cells grown on fructose. When a pH-controlled batch culture was performed using a fermentor at pH 6.2 with H2 and CO2, a maximum of 0.92 g/l of dry cell weight and 339 mM of acetate were produced after 220 h, which were 4.4- and 6.8-fold higher than those produced in the pH-uncontrolled batch culture, respectively. In order to reduce acetate inhibition in the culture medium, a repeated batch culture with cell recycling was performed at a constant pH with H2 and CO2. At a pH of 6.2, the total acetate production reached 840 mmol/l-reactor with 4.7 mmol/l-reactor of total ethanol production after 420 h. ...

- by Yutaka Nakashimada
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- Engineering, Technology, Hydrogen, Carbon Dioxide

This work was to evaluate the potentiality of crude beet molasses (CBM) for ethanol production by yeast fermentation and to examine some physiological parameters that might affect the fermentation efficiency. Twenty-two strains of yeasts were screened for their production of ethanol from CBM; Saccharomyces cerevisiae Y-7 was the strain with the best sugar-ethanol conversion (fermentation efficiency 83"3%) and thus selected for further studies. The atomic absorption analysis of BM ash showed the presence (in order of concentration) of Na +, Ca :+, K +, Mg 2+, Fe -'+, Zn 2+ , Cu2+, pc+ and Mn 2+. CBM was subjected to different treatments to reduce the elements content and to remove the muddy residue. The best results were obtained when CBM was treated with either H2SO 4 or CaL~(P04) 2 and heated to 90°C.

- by reda allam
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- Multidisciplinary, Saccharomyces cerevisiae, Ethanol Production

The batch fermentation process of sugar beet processing intermediates by free yeast cells is the most widely used method in the Autonomous Province of Vojvodina for producing ethanol as fuel. In this study a process and cost model was developed for producing ethanol from raw juice. The model can be used to calculate capital investment costs, unit production costs and operating costs for a plant producing 44 million l of 99.6% pure ethanol annually. In the sensitivity analysis the influence of sugar beet and yeast price, as well as the influence of recycled biomass on process economics, ethanol production costs and project feasibility was examined. The results of this study clearly demonstrate that the raw material costs have a significant influence on the expenses for producing ethanol. Also, the optimal percentage of recycled biomass turned out to be in the range from 50% to 70%.

In this paper, an experimental investigation, an analytical analysis and a numerical model of a typical four-point bending test on a honeycomb sandwich panel are proposed. The honeycomb core is modelled as a single solid layer of equivalent material properties. Analytical and numerical (finite element) homogenization approaches are used to compute the effective properties of the honeycomb core. A general kinematic model (unified formulation) has been adopted and used for the modelling of honeycomb sandwich panel submitted to the bending test. A comparative study of major classes of representative theories has been considered. Qualitative and quantitative assessments of displacement, stress have been presented and discussed.

- by Salim Belouettar
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- Engineering, Materials Engineering, Mechanical Engineering, Chemical Engineering

Bagasse, corn cob, and rice straw agricultural wastes were found to consist of 37, 39 and 34% cellulose and 24, 41 and 22% hemicellulose, respectively, on a dry solid (w/w) basis and thus have the potential to serve as a low cost foodstock for ethanol production. Hydrolysates produced by dilute-acid pretreatment followed by cellulase digestion were evaluated as substrates for ethanol fermentation bySaccharomyces cerevisiae. After pretreatment by 141 mM sulphuric acid, bagasse waste released glucose (134 mg/g) at a higher level than that from corn cob (75 mg/g) and rice straw (8 mg/g). Hydroxymethylfurfural (HMF) levels derived from acid pretreatment of bagasse (1.5 g/l), but not corn cob (0.8 g/l) or rice straw (0.1 g/l) attained levels likely to be toxic (1.5 g/l) forS. cerevisiae growth and ethanol fermentation rates. All three agricultural wastes released likely non-toxic levels of furfural (<0.5 g/l) and lactic acid (negligible for bagasse and rice straw and 0.7 g/l for corn cob). After cellulase saccharification of the dilute-acid pretreated agricultural wastes, the glucose content of corn cob hydrolysates (13 ± 0.17 g/l) was marginally higher than that of bagasse (12 ±0.27 g/l) or rice straw (11 ± 0.07 g/l), yet the ethanol conversion yield byS. cerevisiae on corn cob hydrolysate (0.45 ± 0.006 g/g) was lower than that attained with bagasse hydrolysate (0.49 ± 0.007 g/g). Synergistic adverse effects between furfural and HMF with weak acids, or other lignin derived products in the corn cob hydrolysate are proposed as the effective inhibitor (s) for ethanol fermentation byS. cerevisiae.

- by Ancharida Akaracharanya
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- Microbiology, Medical Microbiology, Saccharomyces cerevisiae, Rice

attributional and consequential approach Brazilian ethanol industrial ecology land use change renewable plastics sugarcane-based LDPE Supporting information is available on the JIE Web site Summary A potential strategy for tackling the negative environmental impact of conventional plastics is to produce them from renewable resources. However, such a strategy needs to be assessed quantitatively, by life cycle assessment (LCA) for example.

- by Anne-marie Tillman
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- Industrial Ecology, Life Cycle Assessment, Multidisciplinary, Land Use Change

Emissions of greenhouse gases such as CO2, CO, CH4 and NOX from fossil fuel use are implicated in climate change. The use of bioethanol is one means to reduce fossil fuel use and emissions of greenhouse gases. This study investigated research to produce ethanol from sugar beet and use as fuel in Turkey. The calculated demand for bioethanol amounted to

- by Ahmet Can Saral
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- Engineering, Technology, Climate Change, Bioenergy

The inhibitory effects of six lignocellulose degradation products on glucose fermentation by Saccharomyces cerevisiae and Zymomonas mobilis on xylose fermentation by Pichia stipitis and Candida shehatae were studied in batch cultures. Toxic compounds were added in varying concentrations and subsequent inhibitions on growth and ethanol production were quantified. Vanillin was shown to be a strong inhibitor of both growth and ethanol production by xylose fermenting yeasts and S. cerevisiae when it was added to the culture media at a concentration of 1 g l−1. Fermentative activities of Z. mobilis were greatly sensitive to the presence of hydroxybenzaldehyde (0.5 g l−1). Analysis of culture media extracts showed that some of the inhibitors, particularly vanillin and furaldehyde, could be assimilated by the tested microbial strains which resulted in the partial recovery in both growth and ethanol production processes on prolonged incubation.

Traditionally, the raw materials for beer production are barley, hops, water, and yeast, but most brewers use also different adjuncts. During the alcoholic fermentation, the contribution of aroma compounds from other ingredients to the final beer flavor depends on the wort composition, on the yeast strain, and mainly on the process conditions. In this context, banana can also be a raw material favorable to alcoholic fermentation being rich in carbohydrates and minerals and providing low acidity. In this work, the objective was to evaluate the performance of wort adjusted with banana juice in different concentrations. For this, static fermentations were conducted at 15°C at pilot scale (140 L of medium). The addition of banana that changed the concentration of all-malt wort from 10°P to 12 and 15°P were evaluated (°P is the weight of the extract or the sugar equivalent in 100 g solution, at 20°C). The results showed an increase in ethanol production, with approximately 0.4 g/g ethanol yield and 0.6 g/L h volumetric productivity after 84 h of processing when concentrated wort was used. Thus, it was concluded that banana can be used as an adjunct in brewing methods, helping in the development of new products as well as in obtaining concentrated worts.

- by Daniela Santos Silva
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- Technology, Production, Food Technology, Biological Sciences
- by Robert Letovsky and +1
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- Education, Energy efficiency, Models, Ethanol Production

Purpose -Over recent the past decades, integrated management systems (IMS) have emerged as one of the major tasks for practising managers and the academic community. In this context, this paper aims at identifying relevant practices related to an IMS in an organisation that belongs to the sugar cane and ethanol agricultural industrial sector in Brazil. Design/methodology/approach -A review of mainstream literature on IMS is conducted followed by case-based research used as the methodological approach. Data were gathered through a questionnaire as well as face-to-face semi-structured interviews. The analysis was done a posteriori to construct the case description and perform the analysis. Findings -Issues that motivated the IMS implementation were identified. The paper also highlights the difficulties experienced and benefits accrued during implementation. The existence of a previous quality management system facilitated the implementation of the IMS. Nevertheless, a longitudinal study is desirable to assess further results in the long term. Research limitations/implications -This work is limited to a single unit of analysis. Therefore, empirical replications in other samples are needed to validate current findings. Originality/value -This is one of the first known studies to investigate the implementation of an IMS in a manufacturing unit that produces sugar and ethanol.

- by Eduardo Satolo
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- Management, Agriculture, Multidisciplinary, Ethanol Production

Saccharum spontaneum is a wasteland weed consists of 45.10 ± 0.35% cellulose and 22.75 ± 0.28% of hemicellulose on dry solid (DS) basis. Aqueous ammonia delignified S. spontaneum yielded total reducing sugars, 53.91 ± 0.44 g/L (539.10 ± 0.55 mg/g of substrate) with a hydrolytic efficiency of 77.85 ± 0.45%. The enzymes required for hydrolysis were prepared from culture supernatants of Aspergillus oryzae MTCC 1846. A maximum of 0.85 ± 0.07 IU/mL of filter paperase (FPase), 1.25 ± 0.04 IU/mL of carboxy methyl cellulase (CMCase) and 55.56 ± 0.52 IU/mL of xylanase activity was obtained after 7 days of incubation at 28 ± 0.5°C using delignified S. spontaneum as carbon source under submerged fermentation conditions. Enzymatic hydrolysate of S. spontaneum was then tested for ethanol production under batch and repeated batch production system using ''in-situ" entrapped Saccharomyces cerevisiae VS 3 cells in S. spontaneum stalks (1 cm Â 1 cm) size. Immobilization was confirmed by the scanning electron microscopy (SEM). Batch fermentation of VS 3 free cells and immobilized cells showed ethanol production, 19.45 ± 0.55 g/L (yield, 0.410 ± 0.010 g/g) and 21.66 ± 0.62 g/L (yield, 0.434 ± 0.021 g/g), respectively. Immobilized VS 3 cells showed maximum ethanol production (22.85 ± 0.44 g/L, yield, 0.45 ± 0.04 g/g) up to 8th cycle during repeated batch fermentation followed by a gradual reduction in subsequent cycles of fermentation.

- by Anuj Chandel
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- Kinetics, Scanning Electron Microscopy, Multidisciplinary, Cellulase

The simultaneous enzymatic saccharification and fermentation (SSF) of corn meal using immobilized cells of Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. The yeast cells were immobilized in Ca-alginate by electrostatic droplet generation method. The process kinetics was assessed and determined and the effect of addition of various yeast activators (mineral salts: ZnSO 4 Á 7H 2 O and MgSO 4 Á 7H 2 O, and vitamins: Ca-pantothenate, biotin and myo-inositol) separately or mixed, was investigated. Taking into account high values of process parameters (such as ethanol concentration, ethanol yield, percentage of the theoretical ethanol yield, volumetric productivity and utilized glucose) and significant energy savings the SSF process was found to be superior compared to the SHF process. Further improvement in ethanol production was accomplished with the addition of mineral salts as yeast activators which contributed to the highest increase in ethanol production. In this case, the ethanol concentration of 10.23% (w/w), percentage of the theoretical ethanol yield of 98.08%, the ethanol yield of 0.55 g/g and the volumetric productivity of 2.13 g/lÁh were obtained.

- by Ljiljana Mojovic
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- Mechanical Engineering, Chemical Engineering, Kinetics, Biotechnology

Bio-ethanol is playing an important role in renewable energy for transport according to Thai government policy. This study aims to evaluate the energy efficiency and renewability of bio-ethanol system and identify the current significant environmental risks and availability of feedstocks in Thailand. Four of the seven existing ethanol plants contributing 53% of the total ethanol fuel production in Thailand have been assessed by the net energy balance method and Life Cycle Assessment (LCA). A renewability and net energy ratio portfolio has been used to indicate whether existing bio-ethanol production systems have net energy gain and could help reduce dependency on fossil energy. In addition, LCA has been conducted to identify and evaluate the environmental hotspots of 'cradle to gate' bio-ethanol production. The results show that there are significant differences of energy and environmental performance among the four existing production systems even for the same feedstock. The differences are dependent on many factors such as farming practices, feedstock transportion, fuel used in ethanol plants, operation practices and technology of ethanol conversion and waste management practices. Recommendations for improving the overall energy and environmental performance of the bio-ethanol system are suggested in order to direct the bio-ethanol industry in Thailand towards environmental sustainability.

- by Shabbir Gheewala and +1
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- Mechanical Engineering, Renewable Energy, Production, Energy
- by R. Agu
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- Engineering, Biological Sciences, Raw materials, Maize