COMBINING MODERATE PULSED ELECTRIC FIELDS WITH TEMPERATURE AND WITH ORGANIC ACIDS TO INACTIVATE ESCHERICHIA COLI SUSPENSIONS

The aim of this work was to study the efficiency of inactivation of Escherichia coli cells in aqueous suspensions using combined moderate pulsed electric field (PEF) and thermal treatments. The inactivation kinetics of E. coli cells in aqueous suspensions (1 wt%) was monitored using conductometric technique. The electric field strength E was within 5-7.5 kV/cm, the effective PEF treatment time was within 0-0.75 s, the pulse duration ti was within 0.3-1 ms, the medium temperature was 30-50°C, and the time of thermal treatment tT was within 0-7000 s. The organic acid concentration was within 0-0.5 g/L.The damage of E. coli was accompanied by release of intracellular components. The synergy between the PEF and thermal treatments in E. coli inactivation was clearly demonstrated. The damage efficiency was noticeably improved by addition of organic acids, especially lactic acid

Optimization of cyclopropane fatty acids production in Yarrowia lipolytica

International audienceCyclopropane fatty acids, which can be simply converted to methylated fatty acids, are good unusual fatty acid candidates for long‐term resistance to oxidization and low‐temperature fluidity useful for oleochemistry and biofuels. Cyclopropane fatty acids are present in low amounts in plants or bacteria. In order to develop a process for large‐scale biolipid production, we expressed 10 cyclopropane fatty acid synthases from various organisms in the oleaginous yeast Yarrowia lipolytica, a model yeast for lipid metabolism and naturally capable of producing large amounts of lipids.The Escherichia coli cyclopropane fatty acid synthase expression in Y. lipolytica allows the production of two classes of cyclopropane fatty acids, a C17:0 cyclopropanated form and a C19:0 cyclopropanated form, whereas others produce only the C17:0 form. Expression optimization and fed‐batch fermentation set‐up enable us to reach a specific productivity of 0.032 g·L−1·hr−1 with a genetically modified strain containing cyclopropane fatty acid up to 45% of the total lipid content corresponding to a titre of 2.3 ± 0.2 g/L and a yield of 56.2 ± 4.4 mg/g

The ECORBIO project in a nutshell and its major achievements

ECORBIO is the acronym for Evaluation of CORrosion issues in advanced BIOrefineries. Advanced biorefining according to IEA task 42 corresponds to sustainable transformation of biomass into a marketable portfolio of products comprising food, feed, biomolecules, biomaterials and energy vectors (see fig.1) . To our knowledge, the ECORBIO project is the first initiative undertaken at EU level focusing on potential corrosion problems inside these new and versatile production systems. The 3 years long research project has been financially supported by CR Picardie (now integrated in the new Region Nord-Pas-de-Calais-Picardie, according to recently redefined French administrative Regions) from 2012 to 2015 as a winning proposal submitted by INERIS (acting as coordinator) and 5 key regional partners (UTC-TIMR/ESCOM, UPJV (through GEC FRE CNRS3580 Unit, LEREM, CETIM and MAGUIN SAS) grouping 2 academic laboratories, 3 technical centres and one industrial partner involved in biorefining as equipment and biorefinery process units supplier. The consortium has developed a multidirectional approach entailing analytical and experimental works, bibliographical review, database setting, exchanges with stakeholders. Key objectives of the project was to identify whether or not corrosion was a issue in modern biorefining, analyze past and current research contributing to put corrosion under control and success obtained so far in the matter, and bring proper contribution to advance new knowledge. As a general introduction to the CORABIO workshop, the purpose of this communication is to remind the delegates of some key contextual facts about corrosion concerns, to provide a first overview of workplan and findings of the project, including a first overview of major learning regarding the various tasks undertaken, lessons from bibliometric indicators, major feedback from incidents, potential corrosive environments induced by key materials like carboxylic acids and ionic liquids, evaluation of the corrosion protocol “C1” recently supporting according to GHS (Global Harmonised System) the classification of substances that must be labelled as “corrosive to metal” substances or mixtures and other experimental developments. Major findings are subject to dedicated talks or posters which are included as specific items in the ECORBIO project

Study of the corrosion of metals in liquids found in biorefineries and in ionic liquids

Biorefineries of the future should be an essential tool for the bio-sourced economy. Understanding the corrosion phenomena in these new installations is essential due to economical and environmental potential aspects. Developing fast running screening tests to evaluate the corrosion rates of various compounds (organic acids or ionic liquids) potentially contributing to corrosive environments on various metals used in adavanced biorefinery pieces of equipment could be strategic to reduce investment and operational maintenance costs and also, increase safety and limit environmental impact from non controlled emissions. This study showed that the regulatory test Cl from CLP is not really adapted to the tested products. It showed that the classification of a product could be different due to experimental duration choice. The innovating IO-LI-TEC screening method could be adapted to study the corrosivity of ionic liquids. It was showed that the influence of impurities was significant. The use of the classical amperometry studies could be helpful to study the behavior of different metals in products from biorefineries

Corrosive properties of liquid fractions issued from lignocellulosic biomass pretreatment with ionic liquids

The use of Ionic Liquids (ILs) in the lignocellulosic biomass pretreatment necessary to 2nd generation bioethanol production has gained considerable attention in recent years [1]. Owing to an imminent scale-up phase, the study of corrosive properties of ILs is necessary to anticipate future problems, which could be encountered at industrial scale, especially considering that annual direct cost worldwide for corrosion is over 3% of the world's Gross Domestic Product [2]. Thus prevention and reduction of corrosion in lignocellulose pretreatment, as more globally in major processes of advanced biorefining [3] is of great scientific, technological and economical interest. Consequently the purpose of the present work was to study the corrosive properties of liquid fractions issued from pretreatment of various lignocellulosic biomasses: model cellulose, oak sawdust or spruce sawdust. Liquid fractions were collected at two steps: 1) after lignocellulosic biomass pretreatment with 2 ILs: 1-ethyl-3- methylimidazolium acetate or 1-ethyl-3-methylimidazolium methylphosphonate, and 2) precipitation using water or ethanol as an anti-solvent. The corrosive behavior of the fractions collected was determined by mass loss of S235 carbon steel and corrosion pit observation of 316L stainless steel, with a rectangular form (1 x 4 x 0.1 cm) during 7 days at 100°C. The morphology and the elemental composition of the corroded metal surfaces resulting of exposition to the pretraitment liquid fractions, were analyzed by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDX). Our results showed that corrosion rates for S235 carbon steel varied from fairly low to 400 μm/year depending on the nature of the liquid fraction, whereas corrosion pit was not observed in 316L stainless steel, regardless of the liquid fraction used. Micrographies of S235 carbon steel specimens, revealed the formation of a passivation layer when [Emim]+[Methylphosphonate]- is used for pretreatment contrary to the used of [Emim]+[Acetate]-. In addition, biomass nature (cellulose, oak sawdust or spruce sawdust) and anti-solvent (water or ethanol) used for regeneration step (precipitation) influenced the morphology and the elemental composition at the surface of metal specimens with both [Emim]+[Acetate]- and [Emim]+[Methylphosphonate]- ILs. We are grateful to the European Union/FEDER and Conseil Regional de Picardie (CRP) for funding this project (ECORBIO). Europe is engaged in Picardy with the European Fund of Regional Development (FEDER)

Material behavior study in corrosive environments reflecting biorefineries and biogas installations

Many studies present biorefineries as strategic tools for the future bioeconomy. The development of new processes in integrated biorefineries and related (although so far limited to 1G biorefineries) experience in the domain would militate for accessing updated knowledge to put corrosion economic impact under control and thus optimize CAPEX and OPEX of such production facilities. To identify biorefinery induced specific corrosion issues innovative experimental approaches are proposed in the ECORBIO project. We proposed to measure in laboratory the effects of industrial products such as organics acids and by-products (molasses, vinasses, condensates, digestates) on steel and stainless steel samples, in corrosive environments reflecting as far as we know biorefineries and biogas installations. Corrosion tests on selected S235, 3CR12, 316L metal samples were carried out in corrosive environments reflected by liquid and vapour phases of solutions of succinic acid, citric acid, lactic acid and acetic acid. Sulfuric acid and water are chos~n as references solutions in the study. Laboratory reflux apparatus was used in the order to stabilize the system to 100°C. Anaerobic fermentation tests on S235, 3CR12, 316L were also carried out in digestates with or without glycerol. An incubator apparatus was used in the order to stabilize system to 32 °C and 160 rpm. Corrosion kinetics was assessed in a first approach by visuals observations of samples and by mass loss data analysis. S235 steel samples are the most damaged and have the greatest mass loss (Fig.1 and 2). During the corrosion tests, 3CR12 steels have damages and mass loss higher than 316L steels, which are practically unchanged (Fig.1 and 2). By contrast, during anaerobic fermentation tests, 3CR12 steel samples show substantially more resistance to corrosion in the test environment than for 316L steel (Fig.1 and 2). Thereafter, metal concentrations in aggressive solutions will be assessed and related to mass loss, in the order to establish a metals extracting model

Learning on potential corrosive environments in advanced biorefineries

Advanced biorefining is a versatile concept that promotes the sustainable production of a portfolio of biobased products including biomolecules, biomaterials, bioenergy and energy vectors from various biomass resources and residues. Early development of so-called 1G (first generation) biorefineries that were essentially concentrating on mass production of biodiesel or bioethanol has shown a number of limitations in the related value chains in terms of sustainability issues. Among those issues, a number of corrosion problems have been reported and identified, at least partially understood and sometimes solved. We can quote for example the corrosion of some metallic components of engines due to heat driven conversion of ethanol into acidic species before combustion, the high temperature corrosion in biomass burning furnaces due to the presence of alcali salts as well as stress corrosion cracking in ethanol carbon steel tanks and in pipelines. However no global assessment of corrosion issues in the biorefineries of the future has been performed so far, hence leaving significant interrogation where research efforts have to be deployed to accompany their sustainable implementation. This paper first offers a first overview of the topic from results obtained from the ECORBIO project (for Evaluation of CORrosion in BIOrefineries of the future), the main aim of which is to cover this gap by delivering useful information to process managers, engineering companies and investors for evaluation of corrosion in bioprocesses. The project (Oct 2012 to March 2016) lies on a diversity of scientific approaches comprising: a) literature review b) analysis of accident statistics, exchanges with stakeholders c) testing with existing and purpose developed procedures with a focus on 'biocorrosion', organic acids and ionic liquids, d) learning on a case study in relation with 2G ethanol one pot process . Preliminary results exposed in this paper comprise: a) the analysis of the corrosive environment potentially developed by key microbial products such as organic acids (lactic acid, acetic acid, succinic acid, citric acid....) with sulphuric and distilled water as reference substances for three different grades of steels ; b) corrosive potencies of some imidazolium and phosphonium based ionic liquids that may play a role e.g. in lignocellulosic biomass defragmentation and/or in cellulose dissolution c) first lessons from experience in biorefining and from more general statistics d) first learnings on the pertinence of the C1 test protocol that is used to state whether or not a given substance (e.g. a process juice) is 'corrosive to metals' as an identified dangerous physico-chemical intrinsic property, according to the recently implemented CLP Regulation in the EU (also included in the Globally Harmonised System at UN level)

Overview of ECORBIO project (10/2012 - 09/2015) evaluation of corrosion issues in biorefineries of the future

Biorefinery is an industrial complex allowing for the valorisation of biomass components from all origins into sustainable molecules, fuels and energy vectors. Biorefinery is therefore a key and versatile industrial concept underpinning advanced and future bioeconomy. Thus the choice of material used to manufacture equipments in these biorefineries is strategic. Indeed, it must be processed taking into account the competitiveness and sustainable development but the decision maker is also confronted with several uncertainty factors (markets? which inputs? Actual versus nominal rate? Legislation? ... ). Due account of regular or local corrosion issues will keep an essential aspect for successful environmental safety, economic sustainability and aging management of metallic material and related key equipment. As a matter of facts, all sectors combined, the toll paid in terms of economic losses caused by corrosion regularly rises up to several percentage points of GDP in industrial countries. The objectives of project ECORBIO are: a) to draw up an initial assessment of the nature and sectorial importance of metallic corrosion; b) to identify and understand the influencing factors of corrosion and c) to provide a first practical contribution to the analysis of the corrosion in biorefineries. First, an analysis of the state of the art (including spinoffs European projects as Aquafit4use) on corrosion in industrial installation will be done and related information were consolidated into a first database. This database multi-tabbed implemented under EXCEL (version 1) has inventoried and described 17 corrosion phenomena, and has listed corrosion potential of tens of chemicals against various metals. Then, we used various experimental and analytical approaches relying on industrial, scientific and technical partnerships bringing actual value. In particular, the effects of industrial products such as organics acids and by-products (molasses, vinasses, condensates, digestates) on steel and stainless steel samples were carried out in the order to study the materials behaviour in corrosive environments reflecting biorefineries and biogas installations. We have also started to explore the relevance of regulatory test C 1 for biorefineries sector in the order to classify the corrosive power of industrial products on steel and stainless steel samples. Subsequently, the ionic liquids corrosive effect on steel and stainless steel samples will be assessed by method IO-LI-TEC 2011 and other pertinen

Corrosive properties of liquid fractions issued from lignocellulosic biomass pretreatment with imidazolium-based ionic liquids : towards a scale up of biorefinery strategy

One of the main challenges of the 21st century is to meet the increasing demand for energy requirements by means of a more sustainable energy supply. The use of ionic liquids (ILs) in the lignocellulosic biomass pretreatment necessary to 2nd generation bioethanol production has gained considerable attention in recent years[1],[2]. Indeed ILs present several advantages including high thermal stability and low volatility, which distinguish them from conventional instable and toxic pretreatments, operating at severe conditions[3],[4]. Owing to an imminent scale-up phase, it is necessary to anticipate future problems which could be encountered at industrial scale. Since the annual direct cost of corrosion worldwide is over 3% of the world's Gross Domestic Product[5], prevention and reduction of corrosion in biorefineries of the future is of great scientific and technological interest and of upmost economic importance. However very few reports concerning the evaluation of corrosion due to ILs in biorefineries are available. Consequently the purpose of the present work was to study the corrosive properties of liquid fractions issued from lignocellulosic biomass valorization into second generation bioethanol after each step of the process: pretreatment with imidazolium-derived ILs (2% w/v biomass-IL, 110°C, 40 min), cellulose regeneration, enzymatic saccharification to release fermentable sugars and alcoholic microbial fermentation. Two industrial metals were tested using mass loss techniques: S235 carbon steel and 316L stainless steel. Corrosion rates measured on 316L stainless steel after 7 days at 100°C were found negligible (below 1 μm/year) whereas rates for S235 carbon steel tested under identical conditions, varied until 400 μm/year depending on the nature of the liquid fraction. Our results indicated that IL anionic moiety played an important role in the IL corrosive properties, as EmimMethylphosphonate (31-390 μm/year) was more corrosive than EmimAcetate (0-100 μm/year), depending on liquid fraction nature. Lignocellulosic biomass components dissolved on ILs after pretreatment did not increase the corrosive power. In contrast, the addition of an anti-solvent (water or ethanol) for the regeneration step seemed to increase the corrosion. Both enzymatic saccharification and microbial fermentation steps did not influence significantly the corrosive properties of the liquid fractions