Potential For Biofuel Production Research Articles

Influence of Ca(OH)2 on ash melting behaviour of woody biomass

Woody biomass is a renewable source offering high potential for production of bio-fuels, -chemicals and -energy. During the outdoor storage of biomass biodegradation processes take place, which leads to mass reduction up to 30 wt%. To avoid these mass losses, the biomass was mixed with Ca(OH)2 in different ratios. To ensure, that this additive does not negatively influence further thermo-chemical conversion of biomass (e.g. by fluidized bed combustion), the spruce and poplar ash with and without additive was tested using ash melting microscopy. It was demonstrated that all the characteristic temperatures (DT, HT, FT) were significantly higher than the thermo-chemical conversion process temperatures in a fluidized bed. Thus it could be pointed out that the addition of Ca(OH)2 does not negatively influence ash melting behaviour, ash melting temperature respectively.

Seed germination and performance of sunflower seedlings submitted to produced water

ABSTRACT The use of produced water becomes an option in the irrigation of non-food crops with potential for biofuel production. However, its effects on different stages of plant development and mainly on seed germination should be known. The study was conducted to evaluate the performance of sunflower seedlings subjected to different types of produced water. An experimental design in a factorial scheme was adopted to evaluate 3 cultivars (Catissol 01, Embrapa 122 and IAC Iaramã) and 6 types of water (distilled water - control, public-supply water, water resulting from the water and oil separation process - WOS, filtration in sand filter - SAF, filtration in sand + charcoal filter - SCF, and filtration in sand + osmosis filter - SOF). In addition, the substrate was moistened with polyethylene glycol (PEG) solutions, simulating the osmotic potentials of the evaluated waters, and a sensitivity test was conducted with lettuce seeds under conditions similar to those adopted for sunflower. The cv. Catissol showed higher percentages of germination and vigor of seedlings, regardless of the water used. There was a trend of reduction in germination and vigor of seedlings with the use of produced water treated with the WOS, SAF and SCF systems. All water potentials simulated by PEG solutions reduced the germination and vigor of lettuce seeds, and the effect was more pronounced for the WOS system. SOF was the only one capable of making the produced water non-toxic to sunflower seeds and lettuce seedlings.

Effects of milling combined with extremely low-liquid ammonia (ELLA) pretreatment to enhance enzymatic hydrolysis of corn stover

Lignocellulosic biomass is one of the largest carbohydrate sources and has huge potential for biofuels production. However, the problem with lignocellulosic feedstock is that it has useful sugars locked in by lignin, hemicellulose, and cellulose. Some kind of pretreatment; therefore is needed to make carbohydrate accessible which later can be fermented to produce ethanol. The results from this research indicated that the yields of glucan (93%) and xylan (82.8%) were improved by using milling combined with ELLA pretreatment. The optimal enzymatic hydrolysis efficiencies were obtained under 10 min for ball milling time, pretreatment at 1 h, temperature at 150°C, S/L = 0.5 and ammonia loading at 0.25 g-NH3/g-biomass. This method reduced the pretreatment time and short milling time and thus has potential of reducing the energy consumption and promising the application in the large scale.

The Empirical Research of The Potential, Awareness and Current State of Agricultural Waste Use to Ensure Energy Autonomy of Agricultural Enterprises of Ukraine

Today, the issues of waste management are complex, because they relate to various aspects – resource conservation, environmental safety of mankind, ensuring competitiveness at micro, macro and mega-levels. The study is devoted to the analysis of the potential, awareness and current state of use of agricultural waste to ensure energy autonomy of agricultural enterprises of Ukraine on the basis of the experimental study, conducted by the authors using a mixed method. The main tool in the study was the survey developed by the authors, which was filled out by the owners of agricultural enterprises in Ukraine. The development of the survey was accompanied by the authors' hypotheses regarding the need for energy autonomy of agrarian enterprises; main sources of information on opportunities and state support for energy use of waste; potential and current state of bioproduction in agrarian formations. Authors acknowledged that both the crop and livestock industries lead to the generation of waste that has the potential to produce biofuels (solid – pellets, briquettes; gaseous – biogas). The study confirmed that the costs for providing agrarian enterprises themselves with fuel and energy resources in Ukraine are quite high, and the bioenergy potential of waste to replace traditional energy resources is practically not used. Further studies will cover a range of questions regarding the extension of the geography of the survey to the whole territory of Ukraine, the specification of hypotheses based on the preliminary questionnaire, the hypothesis testing and the correlation between different indicators of the agrarian waste potential for biofuel production and the efficiency of substitution of traditional energy with biofuels.

Microalgal Cultivation in Secondary Effluents: Enhancement of Algal Biomass, Nutrient Removal, and Lipid Productivity

The growth performance, nutrient removal, lipid accumulation and morphological changes of Cyanobacterium aponinum OUC1 and Scenedesmus obliquus which were cultured in secondary effluents from two wastewater treatment plants: Tuandao Wastewater Treatment Plant (ETD) and Licun River Wastewater Treatment Plant (ELR) were investigated. The results showed that both C. aponinum OUC1 and S. obliquus have superior growth performances in both undiluted effluents, while the better of them was that in ETD effluent, with cell densities of C. aponinum OUC1 and S. obliquus increased by 159% and 66% over that of BG11 (control), respectively. Regarding nutrient removal, S. obliquus could completely remove inorganic phosphorus, and decrease ammonia nitrogen in ETD effluent by 81%. In addition, both C. aponinum OUC1 and S. obliquus cultivated in ETD exhibited extraordinary potential for biofuel production, increasing lipid productivities by 133% and 89% of that cultivated in ELR, respectively. As to ultrastructural changes, the differences in the lipoidal globules and glycogen granules of S. obliquus and C. aponinum OUC1 among the ETD and ELR treatments were mostly related to phosphorus limitations. The findings from this research reveal the probability using the secondary effluents as cultivation media to enhance algal biomass, nutrient removal and lipid productivity.

Improving ‘Lipid Productivity’ in Microalgae by Bilateral Enhancement of Biomass and Lipid Contents: A Review

Microalgae have received widespread interest owing to their potential in biofuel production. However, economical microalgal biomass production is conditioned by enhancing the lipid accumulation without decreasing growth rate or by increasing both simultaneously. While extensive investigation has been performed on promoting the economic feasibility of microalgal-based biofuel production that aims to increase the productivity of microalgae species, only a handful of them deal with increasing lipid productivity (based on lipid contents and growth rate) in the feedstock production process. The purpose of this review is to provide an overview of the recent advances and novel approaches in promoting lipid productivity (depends on biomass and lipid contents) in feedstock production from strain selection to after-harvesting stages. The current study comprises two parts. In the first part, bilateral improving biomass/lipid production will be investigated in upstream measures, including strain selection, genetic engineering, and cultivation stages. In the second part, the enhancement of lipid productivity will be discussed in the downstream measure included in the harvesting and after-harvesting stages. An integrated approach involving the strategies for increasing lipid productivity in up- and down-stream measures can be a breakthrough approach that would promote the commercialization of market-driven microalgae-derived biofuel production.

Correlations between the compressive strength of the hydrochar pellets and the chemical components: Evolution and densification mechanism

Hydrochars of cotton stalk (CS) at the hydrothermal temperature of 180−280 °C and the retention time of 0−120 min were used for the purpose of developing fuel pellets. Subsequently, the physical properties and combustion characteristics of the hydrochar pellets were evaluated to assess the solid biofuel production potential. Then, the hydrochar samples were analyzed by FTIR, TGA, XRD, and SEM, aiming to investigate the evolution mechanism of the chemical compositions (hemicellulose, cellulose, and lignin) with the increasing hydrothermal temperatures and their effects on the compressive strength of the hydrochar pellets. The results indicated that the hydrochar pellets exhibited higher fixed carbon contents, elevated heating values, enhanced physical properties, and more stable combustion characteristics than the raw biomass pellets. Moreover, the skeleton structure of the crystalline cellulose was the critical factor affecting the compressive strength of the hydrochar pellets. In parallel, lignin was observed to be beneficial for fabricating solid bridges and also exhibited a substantial influence on the bonding performance. However, the crystalline cellulose completely decomposed into amorphous carbon, and the high carbonization degree of the lignin caused it to lose its bonding capacity, which led to a sharp decrease in the compressive strength of the hydrochar pellets pretreated at 280 °C to 2.9 MPa, lower than the CS pellets (4.2 MPa). Finally, the pictorial depiction of the chemical components’ structural characteristics exhibited in the hydrothermal carbonization process was displayed along with their influences on the hydrochar densification process.

Direct Fermentation of Oil Palm (Elaeis guineensis) Trunk Sap to Bioethanol by Saccharomyces cerevisiae

Oil palm agricultural biomass has a great potential for biofuel production due to its abundance and less pretreatment needed. In this study, bioethanol production from oil palm trunks sap was carried out by using yeast Saccharomyces cerevisiae. The suitability of the oil palm trunk sap for bioethanol production was tested by investigating the relationship between the oil palm trunk sap concentration and ethanol produced. The fermentation was conducted in static condition and without pH adjustment using 60, 80, and 100% oil palm trunk sap concentration. Results showed that the highest bioethanol production rate was achieved for 100% oil palm trunk sap (1.033 g/L.h), followed by 80% (0.744 g/L.h), and 60% (0.645 g/L.h). These results were influenced by the presence of sugars in the initial sap, suggesting that high substrate concentration does not inhibit bioethanol production. Therefore, the oil palm trunks sap showed significant potential as a renewable feedstock for the production of bioethanol without dilution.

Combining expansion in pulp capacity with production of sustainable biofuels – Techno-economic and greenhouse gas emissions assessment of drop-in fuels from black liquor part-streams

Drop-in biofuels from forest by-products such as black liquor can help deliver deep reductions in transport greenhouse gas emissions by replacing fossil fuels in our vehicle fleet. Black liquor is produced at pulp mills that can increase their pulping capacity by upgrading some of it to drop-in biofuels but this is not well-studied. We evaluate the techno-economic and greenhouse gas performance of five drop-in biofuel pathways based on BL lignin separation with hydrotreatment or black liquor gasification with catalytic synthesis. We also assess how integrated biofuel production impacts different types of pulp mills and a petroleum refinery by using energy and material balances assembled from experimental data supplemented by expert input. Our results indicate that drop-in biofuels from black liquor part-streams can be produced for ~80 EUR2017/MWh, which puts black liquor on the same footing (or better) as comparable forest residue-based alternatives. The best pathways in both production routes have comparable costs and their principal biofuel products (petrol for black liquor gasification and diesel for lignin hydrotreatment) complement each other. All pathways surpass European Union’s sustainability criteria for greenhouse gas savings from new plants. Supplementing black liquor with pyrolysis oil or electrolysis hydrogen can improve biofuel production potentials and feedstock diversity, but better economic performance does not accompany these benefits. Fossil hydrogen represents the cheaper option for lignin hydrotreatment by some margin, but greenhouse gas savings from renewable hydrogen are nearly twice as great. Research on lignin upgrading in industrial conditions is recommended for reducing the presently significant performance uncertainties.

Characteristics, composition and functional properties of seeds, seed cake and seed oil from different Brassica carinata genotypes

Carinata (Brassica carinata) is an oilseed crop with potential in biofuel production and livestock feed. The present research was conducted to evaluate twenty Brassica carinata genotypes used in breeding programs to develop commercial production of Brassica carinata with low levels of erucic acid. The following characters were evaluated: oil contents, fatty acid profiles, physicochemical characteristics of oils, as well as the content of protein, total phenolic compounds, and the antiradical activity of Brassica carinata defatted seed cake. The oil analysis indicated desirable quality, including low percentages of free fatty acids (FFA), high amounts of unsaponifiable matter (USM), and low values for primary and secondary oxidation products that were under the regulated limits. The oil contents of the samples varied between 27.0 and 39.2%. A total of 16 fatty acid compositions were identified in different samples. As compared to the commercial canola oil, it was observed that Brassica carinata 14C genotype had quite similar fatty acid composition. Total phenolics and protein contents of Brassica carinata cake extract varied from 43.2 to 132 mg/100 g and from 24.6 to 35.4%, respectively. It can be noted that Brassica carinata genotype 14C with low erucic acid (EA) and high oleic acid contents consider as an edible oil cultivar. Regarding EA, the genotypes 3C, 10C, and 17C with low EA content could be recommended as a basis for further breeding programs. Brassica carinata cake from different genotypes might be a valuable source of natural antioxidants due to their antioxidant capacities and free radical scavenging potential.

An assessment of feasibility and potential of gaseous biofuel production from agricultural/animal wastes: a case study

The increased wastes in the agricultural sector is a domino effect of population growth and the growing demand for food that have put pressure on the agricultural and livestock farming sectors for more production. Biomass is currently a major source for replacing fossil fuels driven by their future depletion and current environmental impacts as a result of their unbridled consumption. Anaerobic digestion of biomass is a known technology effective in producing gaseous biofuels. The study comprehensively reviews the potential of producing gaseous biofuels from agricultural residues including sugarcane, apple, sugarbeet, wheat, potato, rice, barley, alfalfa, grapes, corn, and dates and also from animal wastes including livestock and poultry manure and slaughterhouse wastes (e.g., blood and rumen) in Khuzestan Province, as the hub of Iranian agriculture. These wastes are a known concern of farmers and cannot be put to proper use. One of the best ways to use the above-mentioned wastes is to turn them into biofuels such as biogas. The study results revealed that agricultural wastes could produce over 830 million m3 of biogas, 400 million liters of biobutanol, and 345 million m3 of biohydrogen. The livestock farming sector of Khuzestan is also capable of producing 6 million tons of livestock feces and 0.34 million tons of chicken manure that can be the feedstock for producing 380 million m3 of gaseous biofuel. In addition, slaughterhouse wastes are also another source that can produce around 1030 million m3 of biogas. According to the results, by managing wastes both from the agricultural and livestock sectors in this province, the potential of biogas production can be used for generation of more than 4 TW/year of electricity. The findings of the present investigation could assist policy-makers in making decisions aimed at taking advantage of these renewable resources.

In Silico Study of the Structure and Ligand Interactions of Alcohol Dehydrogenase from Cyanobacterium Synechocystis Sp. PCC 6803 as a Key Enzyme for Biofuel Production.

Alcohol dehydrogenase is one of the most critical enzymes in the production of ethanol and butanol. Synechocystis sp. PCC 6803 is a model cyanobacterium organism that is able to produce alcohols through its autotrophic energy production system. In spite of the high potential for biofuel production by this bacteria, the structure of its alcohol dehydrogenase has not been subjected to in-depth studies. The current study was aimed to analyze the molecular model for alcohol dehydrogenase of Synechocystis sp. PCC 6803 and scrutinize the interactions of different chemicals, including substrates and coenzymes. Also, the phylogenetic tree was provided to investigate the relation between different sources. The results indicated that alcohol dehydrogenase of Synechocystis sp. PCC 6803 has a different sequence compared with other Alcohol dehydrogenases (ADHs) of cyanobacterial family members. Verification of the homology model using Ramachandran plot by PROCHECK indicated that all of the residues are in favored or allowed regions of the plot. This enzyme has two Zn ions in its structure which is very similar to the other Zn-dependent ADHs. Docking studies suggest that this enzyme could have more active sites for different substrates. In addition, this enzyme has more affinity to NADH as a cofactor and sinapaldehyde as a substrate compared with the other cofactor and substrates.

Cultivation of microalgae for biofuel production: coupling with sugarcane-processing factories

BackgroundDespite their potential as biofuel resources, large-scale production of biofuels from microalgae is still uncertain primarily due to a lack of feasibility of the process and that it proves to be capital and energy intensive. Therefore, an integration of microalgal cultivation with other processes for achieving an inexpensive nutrient and energy use is an important issue. In the present study, the potential of the flue gas and the wastewater of a sugar factory to support microalgae growth for biofuel and bio-fertilizer production is evaluated.MethodsThe study was carried out by following a case study approach; an Ethiopian sugarcane-processing factory, Metahara sugar and ethanol production factory, was selected for this purpose. Conceptual microalgal biofuel production was integrated with the real sugarcane-processing factory, and the process was evaluated with regard to the product outputs and energy requirements.ResultsThe integrated process model shows that three products, biodiesel, upgraded biogas, and bio-fertilizer with production capacities of 188 tons/year, 1,974,882 m3/year and 42 tons/year, respectively, were produced. For the production of these products, the electricity and thermal energy demand of the integrated process amounted to 1822.13 and 3244.99 MWh/year, respectively. A sensitivity analysis shows that the oil content of the algae, the nitrogen content of the waste, the oil extraction efficiency, and the transesterification efficiency are the main factors which affect the biodiesel production capacity of the integrated process.ConclusionsThis case study approach investigated the potential of a future possible bio-refinery and environmental pollution reduction concept by integrating microalgae biomass production with sugarcane-processing factory wastes and by-products. It was found that the factory wastes and by-products have a significant potential for a viable biofuel production from microalgae.

A comprehensive characterization of non-edible lignocellulosic biomass to elucidate their biofuel production potential

It is very requisite to demonstrate the characterization of lignocellulosic biomass for converting into renewable fuels and valuable chemicals. In this work, the physicochemical and thermochemical characterization of some non-edible oil seeds such as Putranjiva (Putranjiva roxburghii), Amaltas (Cassia fistula), and Siris (Albizia lebbeck) were carried out by extractive analysis via Soxhlet solvent extraction, compositional analysis, proximate analysis, elemental (CHNSO) analysis, heating value, bulk density, crystallinity index via XRD, functional groups via FTIR, mineral content via EDX, slagging and fouling indices via XRF, and degradation profile via TGA. It was noticed that all seeds consist of a maximum percentage of extractives such as Putranjiva 50.55%, Amaltas 18.22%, and Siris 22.8%. The results showed that these seeds have a higher cellulose content compared with hemicellulose and lignin. Further, it was confirmed from the Van Krevelen diagram, CHO index, as well as devolatilization index. Also, from the kinetic analysis, the activation energy (Ea) obtained of these seeds was in the order of PR > AL > CF. The chemical features and thermal degradation behaviour reaffirmed that these non-edible oilseeds have good energy potential for reproducibility of biofuel and green chemicals production.

Adriatic cyanobacteria potential for cogeneration biofuel production with oil refinery wastewater remediation

Among cyanobacteria isolated from Northern Adriatic five strains were able to grow on oil refinery wastewater. Based on the sequencing of the internal transcribed spacer (ITS region) and morphological features strains were identified as Synechococcus sp. MK568070, Phormidium lucidum MK568072, Neolyngbia sp. MK568073, Pseudanabaena sp. MK568071 and Spirulina subsalsa MK573248. Selected marine cyanobacteria were tested over a range of ammonium (NH4+) concentrations simulating oil refinery effluent conditions. Three strains demonstrated high growth potential in a range 0.8–2.0 mM NH4+. Maximum biomass concentrations in stationary phase were in a range 176–590 mg/l, whereas total lipid yields were in a range 7.63–21.40% of dry weight. Although all species satisfy the criteria for biodiesel production the average degree of unsaturation was lowest in Synechococcus sp. MK568070 and Neolyngbia sp. MK568073. High proportion of polyunsaturated alpha-linolenic acid found in Spirulina subsalsa MK573248 opens up considerations for nutritional, aquaculture or other biotechnology applications of that species.

Field and simulation‐based assessment of vetivergrass bioenergy feedstock production potential in Texas

AbstractVetivergrass [Chrysopogon zizanioides (L.) Roberty] is a multi‐purpose crop that has an untapped potential for biofuel production. We conducted a field study at Temple, TX, to determine plant growth characteristics that make vetivergrass an ideal candidate bioenergy feedstock crop. Overall, the high biomass yield (avg. 18.4 ± 0.7 Mg ha−1) can be attributed to the high leaf area index (LAI, avg. 12.7 ± 2.5) and crop growth rates that ranged from 2.7 ± 0.1 to 15.7 ± 0.1 g m−2 d−1. Plant tissue N and P concentrations ranged from 0.59–1.66% and 0.06–0.15%, respectively. Surprisingly, the radiation use efficiency (RUE, avg. 2.2 ± 0.1 g MJ−1) was not high relative to other highly productive grasses. Biomass yield was highly correlated to plant height (avg. 2.1 ± 0.1 m) and LAI (Pearson, r = 0.96 and 0.77, respectively). Data from the field experiment provided plant coefficients that were used to develop an Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) vetivergrass model to assess dryland and irrigated interannual and spatial biomass yields across Texas. ALMANAC simulated dryland and irrigated yields ranged from 0.8–39.3 (avg. 17.2) Mg ha−1 and 9.1–47.0 (avg. 25.4) Mg ha−1, respectively. There was huge spatial variation in dryland and irrigated yields, with CV values of 20 and 15%, respectively. Similarly, dryland and irrigated inter‐annual yields respectively had CV values of 25 and 17%. State‐wide simulation model assessments complement field studies, and furthermore allow bioenergy companies and investors to better estimate biofuel feedstock potential for new crops such as vetivergrass.

Studies on the Attached Cultivation of Filamentous Oleaginous Microalga Tribonema minus

Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus (hereafter T. minus ) has shown a remarkable potential for biofuel production in terms of its high lipid content. However, the strain has only been cultivated in suspended cultivation systems including open pond and closed photobioreactors. Here, we attempted to study the attached cultivation of T. minus , which might be helpful for its scale-up cultivation and industrial applications. As the results, the optimal conditions for T. minus growth in the attached biofilm are 200 μmol photons m −2 s −1 of light intensity and 5% of CO 2 , and the maximum biomass density of 223 g m −2 has been achieved under the light intensity. The non-woven fabric as substratum was found as the best substratum in thin layer attached bioreactor, on which the average biomass productivity of T. minus is about (9.73 ± 2.19) g m −2 d −1 . Furthermore, two attached bioreactor systems, rotary drum and rotation disc, were designed following the light dilution strategy and introduced into T. minus cultivation. The highest footprint areal biomass productivity of these two systems is 33 and 47.1 g m −2 d −1 , respectively, much higher than that in suspended cultivation system. The results shows that T. minus can be cultured with attached cultivation method to improve its biomass productivity.

A comparative study of seed reserve accumulation in five Styrax species with potential for biofuel production

Carbon competition between starch and oil biosynthesis during seed development of Styrax tonkinensis has been reported, but reserve dynamics indicate an absence of significant carbon competition in other Styrax species. The accumulation of different storage reserves during seed development can be competitive. Carbon competition (i.e., carbon flow into starch instead of oil) has been reported in Styrax tonkinensis (Pierre) Craib ex Hartwich. In this study, developmental patterns in morphology and the accumulation of major biochemical fractions of five other Styrax species (S. calvescens Perkins, S. dasyantha Perk., S. faberi Perk., S. japonicus Sieb. et Zucc., and S. odoratissimus Champ. ex Benth.) were analyzed over 50 days. In all species, kernel fresh matter and dry matter increased during development, while the percent water content trended downwards to lower than 40% at the last sampling date. The time to maturity varied with species, as did the evolution of oil, fatty acids composition, sugar, starch, and protein. Contents of these major reserve fractions per kernel increased with development and were strongly correlated with each other. Final oil concentration ranged from 489 to 548 mg g−1, and the proportions of major fatty acids (palmitic, oleic and linoleic acid) were similar across species (11–15%, 39–41% and 43–47%, respectively). In contrast, starch concentrations never exceeded 7–45 mg g−1, depending on species and developmental stage. Final protein concentration ranged from 165 to 237 mg g−1. A slowdown in the speed of oil accumulation midway during development may occur in S. faberi but was not present in the other species. None of the five Styrax species examined here presented evidence for significant carbon competition between starch and oil accumulation.

Upgrading of microalgal consortia with CO2 from fermentation of wheat straw for the phycoremediation of domestic wastewater

Algae have been considered as a best feedstock for combating CO2. In the present study, two mixed microalgal cultures i.e. MAC1 and MAC2 were evaluated in batch mode with an extraneous supply of CO2 from the fermentation of wheat straw. Both the mixed cultures displayed promising CO2 sequestration potentials of 287 and 263 mg L−1d−1, respectively. The removal efficiencies in terms of ammonium, phosphate, chemical oxygen demand, and nitrate were found to be 87%, 78%, 68% and 65%, respectively. Enriching the tolerance of the microalgal consortia to CO2 supply and wastewater as the nutrient source significantly enhanced the lipid production for both the microalgae consortia. Lipid contents of MAC1 and MAC2 were observed to be 12.29 & 11.37%, respectively while the biomass yield from both the consortia was 0.36 g L-1. Total chlorophyll and protein contents of MAC1 and MAC2 were 14.27 & 12.28 µgmL−1 and 0.13 & 0.15 mgmL−1, respectively. Both the consortia found to have significant potential for CO2 sequestration, wastewater remediation and biofuel production.

Spectroscopic/Microscopic Elucidation for Chemical Changes During Acid Pretreatment on Arundo donax

The Arundo donax is a typical fast-growing species from the family Gramineae, which is widely cultivated in China. With a huge yield of A. donax in China, this plant offers great potential for biofuels production. The different types of organization of cell and the tissue in the A. donax could influence the efficiency of enzymatic hydrolysis. In this study, A. donax was subjected to 0.5% (w/w) sulfuric acid (H2SO4) for pretreatment at 140°C for 10 min, 20 min, 40 min, and 60 min, respectively. The changes in microstructure, chemical composition, topochemical properties were comprehensively analyzed. Using a series of spectroscopic and microscopic techniques including Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), polarized light microscopy (PLM), and confocal Raman microscopy (CRM) to obtain the correlative structural and chemical information. Analysis results of chemical composition, FT-IR spectra and XRD indicated that with increasing reaction time, more hemicellulose and lignin would be removed. Correspondingly, there was an obvious increase of the cellulose relative crystallinity via extending reaction time. Results of the PLM observations showed that the birefringence gradually dimmed due to the diminishing of the cellulose component. Furthermore, the CRM mapping images showed the lignin component in compound middle lamellar (CML) was difficult to remove relatively as compared with that in secondary walls. These results indicated that the combination of spectroscopic and microscopic elucidation could give an insightful understanding of chemical changes in cellular level during pretreatment.