Biorefinery Scheme Research Articles

Bio-oil based biorefinery strategy for the production of succinic acid

BackgroundSuccinic acid is one of the key platform chemicals which can be produced via biotechnology process instead of petrochemical process. Biomass derived bio-oil have been investigated intensively as an alternative of diesel and gasoline fuels. Bio-oil could be fractionized into organic phase and aqueous phase parts. The organic phase bio-oil can be easily upgraded to transport fuel. The aqueous phase bio-oil (AP-bio-oil) is of low value. There is no report for its usage or upgrading via biological methods. In this paper, the use of AP-bio-oil for the production of succinic acid was investigated.ResultsThe transgenic E. coli strain could grow in modified M9 medium containing 20 v/v% AP-bio-oil with an increase in OD from 0.25 to 1.09. And 0.38 g/L succinic acid was produced. With the presence of 4 g/L glucose in the medium, succinic acid concentration increased from 1.4 to 2.4 g/L by addition of 20 v/v% AP-bio-oil. When enzymatic hydrolysate of corn stover was used as carbon source, 10.3 g/L succinic acid was produced. The obtained succinic acid concentration increased to 11.5 g/L when 12.5 v/v% AP-bio-oil was added. However, it decreased to 8 g/L when 50 v/v% AP-bio-oil was added. GC-MS analysis revealed that some low molecular carbon compounds in the AP-bio-oil were utilized by E. coli.ConclusionsThe results indicate that AP-bio-oil can be used by E. coli for cell growth and succinic acid production.

Metrics for evaluating the forest biorefinery supply chain performance

For sustainable decision-making regarding biorefinery strategies, different criteria, i.e. economic, environmental, social, should be considered. However, the economic criteria typically do not consider market volatility, whereas today's market involves price and demand volatilities. Biorefinery strategies must be flexible to be robust to market volatility. Therefore, relevant metrics must be developed to quantify the system's performance against volatility. This paper presents metrics of flexibility and robustness which analyze the performance of the supply chain in a dynamic environment, providing additional information along with economic metrics. In this paper, the link between the two metrics, and how profitability and robustness change with flexibility are discussed. The results reveal that, although profitability does not always increase with more flexibility and there is an optimum level of flexibility, the system's robustness is improved by increasing flexibility. Moreover, a “conditional value-at-risk” parameter is introduced to show what patterns of sale lead to highest profit and robustnestness.

Effect of metal–support interaction on the selective hydrodeoxygenation of anisole to aromatics over Ni-based catalysts

Hydrodeoxygenation (HDO) of anisole has been often investigated in connection with biofuel production by bio-oil upgrading, because this molecule is representative of the methoxyphenyl components generated by flash pyrolysis of lignocellulose biomass. In the present work a series of Ni-containing (20wt% loading) catalysts based on carriers as diverse as SBA-15, Al-SBA-15, γ-Al2O3, microporous carbon, TiO2 and CeO2 were selected in order to investigate the possible influence of metal–support interactions on the selectivity of anisole HDO toward aromatic products. Both, supports and catalysts were extensively characterized by N2 adsorption–desorption isotherms, X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR) and ammonium programmed desorption (NH3-TPD). Subsequently, the catalysts were tested for the hydrodeoxygenation of anisole in a continuous flow high pressure reactor. Under low hydrogen pressure (3bars) and moderate temperature (290–310°C) and space velocity (20.4 and 81.6h−1), these catalysts show a very high HDO activity that, for most of them approaches to 100%. Differences in product distribution among the catalysts are attributed not only to variations in the dispersion of the active phase, but also to the influence of the support properties in tuning its reactivity. In particular, acidity of the support is very relevant because strong acid sites may contribute the hydrogenolysis of anisole, while metallic sites will further hydrogenate intermediate compounds to yield cyclohexane. Therefore, the selective production of aromatics, from biomass derived feedstock in a biorefinery scheme can be promoted by an adequate selection of the catalysts characteristics. In this respect, a maximum yield of 64% of benzene was obtained in this study over Ni/C catalysts.

Synergistic benefits of ionic liquid and alkaline pretreatments of poplar wood. Part 1: Effect of integrated pretreatment on enzymatic hydrolysis

An environmentally friendly pretreatment process was developed to fractionate hemicelluloses and lignin from poplar wood by ionic liquid (IL) pretreatment coupled with mild alkaline extraction. Hemicellulosic and lignin fractions were obtained in high yields, amounting to 59.3% and 74.4%, respectively, which can served as raw materials for production of value-added products. The yield of glucose for the integrated pretreated poplar wood was 99.2%, while it was just 19.2% for the untreated material. The synergistic benefits of the removal of lignin and hemicelluloses, the increase of the cellulose surface area, and the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase resulted in the high glucose yield for the integrated pretreated substrate. Therefore, the IL based biorefining strategy proposed can integrate biofuels production into a biorefinery scheme in which the major components of poplar wood can be converted into value-added products.

Systematic screening of biorefinery technologies at the early stage of design

Improving technology readiness and government support have helped some forestry companies to continue to develop their biorefinery strategies over the past few years, including that for ethanol production in some cases. These developing technologies have been proven at various scales, and data required for their evaluation are typically scarce and uncertain. How can forestry companies select the “best” technology among the many options available to them, given this complex and uncertain landscape? The objective of this paper is to demonstrate the use of an early stage design tool for screening biorefinery technologies, using ethanol production as an example. A set of multidisciplinary criteria are defined that can be interpreted by a stakeholder panel, and calculated based on publically-available data. Then, the criteria are interpreted and weighed using multi-criteria decision-making (MCDM) analysis in order to make a global evaluation of technologies relative to each other, and identify those that should not be further considered.

DEVELOPMENT OF MICROORGANISMS FOR CELLULOSE-BIOFUEL CONSOLIDATED BIOPROCESSINGS: METABOLIC ENGINEERS' TRICKS

Cellulose waste biomass is the most abundant and attractive substrate for “biorefinery strategies” that are aimed to produce high-value products (e.g. solvents, fuels, building blocks) by economically and environmentally sustainable fermentation processes. However, cellulose is highly recalcitrant to biodegradation and its conversion by biotechnological strategies currently requires economically inefficient multistep industrial processes. The need for dedicated cellulase production continues to be a major constraint to cost-effective processing of cellulosic biomass.Research efforts have been aimed at developing recombinant microorganisms with suitable characteristics for single step biomass fermentation (consolidated bioprocessing, CBP). Two paradigms have been applied for such, so far unsuccessful, attempts: a) “native cellulolytic strategies”, aimed at conferring high-value product properties to natural cellulolytic microorganisms; b) “recombinant cellulolytic strategies”, aimed to confer cellulolytic ability to microorganisms exhibiting high product yields and titers.By starting from the description of natural enzyme systems for plant biomass degradation and natural metabolic pathways for some of the most valuable product (i.e. butanol, ethanol, and hydrogen) biosynthesis, this review describes state-of-the-art bottlenecks and solutions for the development of recombinant microbial strains for cellulosic biofuel CBP by metabolic engineering. Complexed cellulases (i.e. cellulosomes) benefit from stronger proximity effects and show enhanced synergy on insoluble substrates (i.e. crystalline cellulose) with respect to free enzymes. For this reason, special attention was held on strategies involving cellulosome/designer cellulosome-bearing recombinant microorganisms.

Techno-economic analysis for a sugarcane biorefinery: Colombian case

In this paper a techno-economic analysis for a sugarcane biorefinery is presented for the Colombian case. It is shown two scenarios for different conversion pathways as function of feedstock distribution and technologies for sugar, fuel ethanol, PHB, anthocyanins and electricity production. These scenarios are compared with the Colombian base case which simultaneously produce sugar, fuel ethanol and electricity. A simulation procedure was used in order to evaluate biorefinery schemes for all the scenarios, using Aspen Plus software, that include productivity analysis, energy calculations and economic evaluation for each process configuration. The results showed that the configuration with the best economic, environmental and social performance is the one that considers fuel ethanol and PHB production from combined cane bagasse and molasses. This result served as the basis to draw recommendations on technological and economic feasibility as well as social aspects for the implementation of such type of biorefinery in Colombia.

Towards sustainable production of clean energy carriers from biomass resources

A great fraction of the world’s energy requirements are presently met through the unfettered use of fossil-derived fuels. However, due to the anticipated demise of these energy sources and the environmental and socioeconomic concerns associated with their use, a recent paradigm shift is to displace conventional fuels with renewable energy sources. Among various alternatives, biomasses have garnered tremendous interests as potential feedstock for clean energy production. While numerous biorefinery schemes and conversion technologies exist for the transformation of biomass into usable energy forms, they are not cost-efficient and economically viable to compete with the existing petroleum-refinery technologies. In particular, the recalcitrant nature of several feedstock presents a major technological obstacle for their processing and transformation. Providentially, the synergistic integration of various biochemical and bioprocessing technologies is aiding in the establishment of future biomass energy programs. This article reviews the state of the art and future challenges in the recent development of biomass and associated transformation technologies for clean production of biofuels.

History and future of world's most advanced biorefinery in operation

Running a biomass biorefinery based on lignocellulosic feedstock is challenging both from a processing point of view as well as from a market point of view. Continuous process and product development is needed to meet the dynamics in the markets. Borregaard in Sarpsborg Norway is one of the most advanced biorefineries in operation today and has more than 40 years experience of running such a biorefinery. Based on this experience and presence in many markets, new strategies for converting lignocellulosic biomass to biochemicals and biofuels in a sustainable and profitable way has been implemented. The company is loyal to the biorefinery strategy of making the maximum amount of valuable products out of the biomass. Examples of potential new product lines are microfibrillar cellulose (MFC), water soluble specialty lignins from other sources than wood, lignocellulosic ethanol, proteins and sugar based chemicals. Both experience from the long history of running a biorefinery as well as the main development routes for future new bioproducts is analyzed and discussed.

Solvent‐Free Catalytic Depolymerization of Cellulose to Water‐Soluble Oligosaccharides

The use of cellulose is hampered by difficulties with breaking up the biopolymer into soluble products. Herein, we show that the impregnation of cellulosic substrates with catalytic amounts of a strong acid (e.g., H(2)SO(4), HCl) is a highly effective strategy for minimizing the contact problem commonly experienced in mechanically assisted, solid-state reactions. Milling the acid-impregnated cellulose fully converts the substrate into water-soluble oligosaccharides within 2 h. In aqueous solution, soluble products are easily hydrolyzed at 130 °C in 1 h, leading to 91 % conversion of the glucan fraction of α-cellulose into glucose, and 96 % of the xylans into xylose. Minor products are glucose dimers (8 %), 5-hydroxymethylfurfural (1 %) and furfural (4 %). Milling practical feedstocks (e.g., wood, sugarcane bagasse, and switchgrass) also results to water-soluble products (oligosaccharides and lignin fragments). The integrated approach (solid-state depolymerization in combination with liquid-phase hydrolysis) could well hold the key to a highly efficient "entry process" in biorefinery schemes.

Potential of hydrothermal treatments in lignocellulose biorefineries

AbstractThe aqueous fractionation of native lignocellulosic materials with hot, compressed water (also known as hydrothermal processing or autohydrolysis) has been proposed as a fractionation method for biorefineries, as it enables the simultaneous removal of water‐soluble extractives and the solubilization of hemicelluloses, yielding a solid phase enriched in lignin and cellulose. When the operation is carried out under favorable conditions, the liquid phase from autohydrolysis contains valuable products derived from hemicelluloses, including oligosaccharides that keep the major structural features of the polymer (including substitution by acetyl groups). Post‐hydrolysis of oligosaccharides in media catalyzed by acids or enzymes yields fermentable media containing hemicellulosic sugars; whereas harsh acid hydrolysis conditions result in the production of levulinic acid. Subsequent delignification of autohydrolyzed solids enables the separation of the three major lignocellulose components (hemicelluloses, cellulose, and lignin). As an alternative way for using autohydrolyzed solids, they can be used as substrates for the enzymatic hydrolysis of cellulose, leaving lignin as a solid by‐product. The sustainable manufacture of materials, fuels and chemicals from the biorefinery schemes cited above is discussed. Particular attention is paid to hemicellulose‐derived products. © 2011 Society of Chemical Industry and John Wiley & Sons Ltd

Steam Reforming of Bio-Oil Aqueous Fractions for Syngas Production and Energy

The biorefinery concept has been proposed as a route map to convert biomass into fuels and chemicals, maximizing economic and environmental benefits while minimizing pollution. A biorefinery strategy based on fast pyrolysis is proposed following a two-stage process, where biomass is first subjected to fast pyrolysis, optimized to collect up to 75% (per unit weight of biomass) of a liquid fraction called bio-oil. This bio-oil or its fractions can be upgraded in a second step to different chemicals, to a syngas and/or to energy. In particular, the catalytic steam reforming of the aqueous fraction of bio-oil obtained by fractionation with water is one of the most attractive possibilities for bio-oil upgrading, yielding a H2-rich syngas with low CO content. From the results obtained, it can be concluded that the best alternative for the catalytic steam reforming process is hydrogen production through further purification of the gas obtained.

Production of xylo-oligosaccharides from Miscanthus x giganteus by autohydrolysis

Xylo-oligosaccharides were obtained from Miscanthus x giganteus. The process was designed as a biorefinery scheme, which seeks the separation of the three main components: cellulose, hemicelluloses, and lignin. To extract the hemicelluloses, particularly xylans, in an efficient way, Miscanthus was subjected to autohydrolysis. The system was evaluated for the effects of temperature (160 to 200oC) and reaction time (15 to 60 min) on various parameters, reflecting the changes undergone during the process. The results showed that autohydrolysis is a suitable method for obtaining high yields of xylo-oligosaccharides, reaching values close to 65% of the dissolved xylans (based on the initial amount of potential xylose). Analysis of the process by using the severity factor (RO) allowed for the identification of a set of time-temperature values for which the fractionation was optimal.

A physicochemical–biotechnological approach for an integrated valorization of olive mill wastewater

An integrated physicochemical–biotechnological approach for a multipurpose valorization of olive mill wastewaters was studied. More than 60% of the wastewater natural polyphenols were recovered through a solid phase extraction procedure, by employing Amberlite XAD16 resin as the adsorbent and ethanol as the biocompatible desorbing phase. Thereafter, the dephenolized effluent was fed to a mesophilic anaerobic acidogenic packed-bed biofilm reactor for the bioconversion of the organic leftover into volatile fatty acids (VFAs). A VFAs concentration of 19gCODL−1 was obtained, representing more than 70% of the COD occurring in the anaerobic effluent. The biotechnological process was assessed by means of bio-molecular analyses, which showed that the reactor packed bed was mostly colonized by bacteria of the Firmicutes phylogenetic group. The biorefinery scheme developed in this study allowed the obtainment of 1.59g of polyphenols per liter of wastewater treated and 2.72gCODL−1day−1 of VFAs.

A techno-economic analysis of biodiesel biorefineries: Assessment of integrated designs for the co-production of fuels and chemicals

In this work we explore the concept of integrated biorefineries, and we examine alternative schemes for the co-production of biofuels (biodiesel) and chemicals (succinic acid). Four different biorefinery schemes considering the different uses of crude glycerine from the biodiesel process are simulated and compared: (i) the disposal of crude glycerine as a waste, (ii) the purification (through distillation) of crude glycerine to 80%, (iii) the purification of glycerine to 95%. and (iv) the production of succinic acid from glycerine through fermentation. For the latter, we consider the bioprocess that converts the glycerol to succinate, and a downstream separation process that purifies and crystallises our product to the final succinic acid crystals. To apply complex kinetics for the fermentation we have linked Aspen Plus (2006.5) with Matlab (R2007b), where we have used the experimentally-based unstructured model from Vlysidis et al., 2009 and 2010. We first determine the operating parameters of the fermentor that have a significant effect on the economics of this scenario, i.e. the cycle time of the batch fermentation and the water flowrate entering the bioreactor. Subsequently, we perform single- and multi-objective optimisation to maximise the profit and/or to minimise the environmental impact of the overall process. We then analyse and compare the economics of the four different biorefinery schemes by using well-known profitability and/or emission criteria. Furthermore, we carry out sensitivity analysis that takes into consideration price variations for the most important materials and we extract firm conclusions about the profitability of each scenario. It is found that succinic acid co-production can enhance the profit of the overall biorefinery by 60% for a 20 years plant lifetime. These results indicate the importance of glycerol when it is utilised as a key renewable building block for the production of commodity chemicals.

ChemInform Abstract: Recent Advances in the Catalytic Conversion of Cellulose

AbstractReview: ca. 130 refs.

Editorial: Interdisciplinary, International, Inspiring!

Editorial: Interdisciplinary, International, Inspiring!

Biorefinery of Energy Crop Cardoon(Cynara cardunculus l.)-Hydrolytic Xylose Production as Entry Point to Complex Fractionation Scheme

Response surface methodology (RSM) was employed for statistical modeling and optimization of low temperature dilute sulfuric acid hydrolysis of hemicellulose fraction of energy agro-crop cardoon (Cynara cardunculus L.), as an entry point to complex biorefinery scheme. The 23 central composite rotatable design (CCRD) was used to assess the effect of the principal independent process variables (reaction time, temperature and acid concentration) on efficiency and selectivity of heteroxylan conversion to xylose. The second-order polynomial model was fitted to experimental data to find optimal reaction conditions of xylan-to-xylose hydrolysis by multiple regression analysis. The effect of acid concentration (linear and quadratic) was found as a more significant (p=0.001-0.007) for monomeric xylose recovery in solution. The maximal xylose yield of ca. 86% (18.08 g /100 g biomass) was achieved after cardoon hydrolysis at 138.5oC in 1.28% sulfuric acid solution for 52 min, vs. 87% predicted by model. The resulting xyloseenriched substrate revealed low concentration of toxic substances (1.04% furfural, 0.33% 5-hydroxymethylfurfural, 2.03% glucose), providing required quality for subsequent xylose (bio)conversion to final products (e.g. to xylitol). The enzymatic saccharification/digestibility of insoluble residue after hemicellulose removal was improved in four times, resulting in cellulose conversion to fermentable glucose by 76% vs. 19% for unhydrolyzed cardoon.

Selected Process Alternatives for Biomass Refining: A Review

The role of biorefineries in the production of energy and chemicals from biomass of lignocellulosic nature is reviewed. Special attention is devoted to biorefinery schemes dealing with the fractionation of lignocellulosic raw materials by chemical treatments. The potential of hydrothermal treatments as the first stage of future biorefineries is discussed. Special attention is devoted to the low-volume, high-added value products that can be solubilized by this type of technology.

Editorial- Valorization of Agroforest Crops for Biomass Utilization

Editorial- Valorization of Agroforest Crops for Biomass Utilization