Non-edible Lignocellulosic Biomass Research Articles

A study on critical associations of media components on enhanced cellulase production from wild Trichoderma viride and cellulase immobilization on iron-oxide magnetic nanoparticles

Aim: The current study is a preliminary step towards enhancing the cellulase productivity in wild Trichoderma viride which will enable robust valorization of non-edible lignocellulosic biomass through co-generative enzymatic saccharification, specifically concentrating on influence of individual media components on biomass growth and cellulase productivity. Further, cellulase immobilization on iron-oxide magnetic nanoparticles was also achieved that can increase the shelf life of the enzyme. Methodology: The cellulase production in the wild Trichoderma viride was enhanced using media design and formulation. EDC {1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide} functionalized iron-oxide nanoparticles were chosen to act as carriers for cellulase immobilization. The binding efficiency and relative activity were measured in addition to optimal pH and temperature for cellulase bound iron-oxide nanoparticles. Further, the hydrolysis efficiency of immobilized cellulases was also measured after which it was subjected to consecutive hydrolytic cycles to calculate the recycle rate. Results: A maximum growth rate of 60 PCV (Packed cell volume) and total cellulase activity of 7.4 U ml-1 was obtained on media design and formulation. 82.5% binding efficiency was achieved on EDC functionalized iron-oxide magnetic nanoparticles which showed good stability at 5pH and 500C. There was 44.4% activity loss after 5 consecutive hydrolytic cycles which showed steady decline with increased cycle number and finally at the end of the 10th hydrolytic cycle, 22.2% of total relative activity was retained. Interpretation: Unprecedented total cellulase activity from a wild strain was obtained through media design. The stability of cellulases was further enhanced using iron-oxide magnetic nanoparticle immobilization. Key words: Cellulases, Immobilization, Iron-oxide magnetic nanoparticles, Submerged fermentation, Trichoderma viride

From lignocellulosic biomass to chemical precursors: Simultaneous valorization of furfural and levulinic acid over mesoporous acid catalysts

This paper analyses the furfural and levulinic acid aldol condensation over mesoporous acid materials. This process is a promising route to obtain chemical feedstock and biofuel precursors from two of the most available bio-platform molecules produced from nonedible lignocellulosic biomass. Different acid solids were tested (ion-exchange resins, MCM, γ-Al2O3), obtaining the best results with alumina (γ-Al2O3). This material reaches a feasible equilibrium between sustainability (heterogeneous, available, and cheap catalysis, soft temperatures), activity (45 % of levulinic acid conversion, C10s yield of 44 %) and stability (no deactivation observed after four cycles). These results significantly improve those reported in the literature using microporous materials since the adsorption is significantly limited, as demonstrated by the good carbon balance (>95 %), the kinetic model and spent catalyst characterization.

Review on valorization of lignocellulosic biomass for green plastics production: Sustainable and cleaner approaches

Environmental problems associated with world's largest energy source namely fossil fuels are well known. In addition, petroleum and other nonrenewable energy sources are running out and will be depleted soon. However, many polymers are derived from petroleum. In the face of international movement away from oil-based polymers such as, general purpose polystyrene, polypropylene, polyethylene, terephthalate, high density and low density polyethylene, polycarbonate, polyvinyl chloride, and towards a safe and sustainable future, major research labs in the world are trying to uncover the big breakthrough, particularly via utilizing natural/renewable agro-residues as a substrate for green biopolymers. Considering, non-edible lignocellulosic biomass (LCB) as a feedstock for bio-polymers production as it does not interfere with food security, generate no tailpipe emissions, and also lead to reduction in stubble burning. Among possible organic sources of biopolymers, micro- and macro- algae, provides a wide variety of proteins, lipids, polyphenols, and polysachharides which are currently employed for pharmaceutical, packaging, food, and biomedical applications. Current review summarizes the key insights on microbial biopolymer production from LCB and algal biomass by means of circular bioeconomy. Biobased approach will not only reduce the process cost but also generates economy for farmers globally and promotes innovation in domestic manufacturing.

Advances in catalytic valorization of cellulose into value-added chemicals and fuels over heterogeneous catalysts

The valorization of lignocellulose has received increasing attention due to the diminishing of conventional fossil energy (coal, petroleum, and natural gas). Lignocellulosic biomass is the most important form of biomass, which is naturally abundant, widely distributed, easily accessible, and renewable in earth. Upgrading the nonedible lignocellulosic biomass into various fine-chemicals and liquid fuels is of great importance to the sustainable development of mankind and society. Heterogeneous catalysts have played a significant role in the transformation of lignocellulose, owing to their easy recovery, environmentally friendly, and stability feature. This review focuses on the conversion of lignocellulosic biomass into alcohols, acids, furan derivatives, ethylene glycol, and liquid hydrocarbon fuels using heterogeneous catalysts. A brief outlook is supplied at the end of this review to emphasize the challenges and prospective with respective to this interesting and important field.

Advancement of fermentable sugars from fresh elephant ear plant weed for efficient bioethanol production.

Bioethanol is considered one of the most promising next-generation automotive fuels, as it is carbon neutral and can be produced from renewable resources, like lignocellulosic materials. The present research investigation aimed to utilize the elephant ear plant, a hazardous plant (weed) also considered an invasive species, as a font of non-edible lignocellulosic biomass for bioethanol production. The freshly collected elephant ear plant (leaves and stalk) was chopped into small pieces (1–2 cm) and then homogenized to a paste using a mechanical grinder. The sample pretreatment was done by flying ash for three different time durations (T1 = 0 min, T2 = 15 min, and T3 = 30 min) with 3 replications. All treatment samples were measured for total sugar and reducing sugar content. The concentration of reducing sugar archived was T1 = 0.771 ± 0.1 mg/mL, T2 = 0.907 ± 0.032 mg/mL, and T3 = 0.895 ± 0.039 mg/mL, respectively. The results revealed that the chemical composition was different among treatments. The hydrolysis was performed using cellulase enzymes at 35 °C for the hydrolysis process. The hydrolysate was inoculated with 1% of S. cerevisiae and maintained at room temperature without oxygen for 120 h. Bioethanol concentration was measured by using an ebulliometer. The efficient ethanol percentage was 1.052 ± 0.03 mg/mL achieved after the fermentation. Therefore, the elephant ear plant invasive weed could be an efficient feedstock plant for future bioethanol production.

CHEMICAL VALORIZATION OF CELLULOSE FROM LIGNOCELLULOSIC BIOMASS: A STEP TOWARDS SUSTAINABLE DEVELOPMENT

"The potential of non-edible lignocellulosic biomass paves the path to sustainable economy. A large number of valueadded products have been synthesized by the fractionation of the major components of biomass, i.e. cellulose, hemicelluloses and lignin. Cellulose, the most abundant biopolymer on earth, serves as a starting material for the synthesis of various platform chemicals, such as sorbitol, 5- hydroxylmethylfurfural (HMF), dimethylfuran and levulinic acid. Hydrogels and aerogels fabricated from cellulose, modified cellulose or nanocellulose have proved valuable in a wide range of such as biomedical, food and technological applications. Cellulose-based polymers or bioplastics also emerged as an alternative to fossil fuel-based polymers. In this review, chemical paths to valorize plant cellulose for producing various value-added products have been discussed. The major challenge for valorization is the development of novel and green synthesis methods with simultaneous focus on an integrated approach."

One-pot hydrogenolysis of cellulose to bioethanol over Pd-Cu-WOx/SiO2 catalysts

The chemo-catalytic production of ethanol from nonedible lignocellulosic biomass is essential for mitigating energy shortage. In this work, we developed a multifunctional Pd-Cu-WOx/SiO2 catalyst for the one-pot aqueous-phase conversion of cornstalk-derived cellulose to ethanol with a yield of 42.5C% at 300 °C and 4 MPa H2. Kinetic studies demonstrated that the transformation of cellulose to ethanol followed a number of consecutive steps namely, cellulose hydrolysis to glucose with H+ in hot water (k1), glucose conversion to glycolaldehyde over W species (k2), glycolaldehyde hydrogenation to ethylene glycerol (EG) over Pd (k3), and EG hydrogenolysis to ethanol over Cu (k4, rate-determining step). The individual rates were well balanced on Pd, Cu, and WOx species to achieve an ethanol formation rate of 0.163 g·gCat.−1h−1. The addition of Au to Cu-WOx species led to a relatively low k3 and thus the formation of a substantial amount of humins, while the Ru introduction catalyzed the over-hydrogenolysis of ethanol to methane and ethane with a high rate, thereby lowering the selectivity to ethanol. The characterization results showed that both the electronic properties of Cu+ species and the Cu+/Cu0 ratio on the Pd-Cu-WOx/SiO2 catalyst contributed to a specific CO bond cleavage, especially for EG hydrogenolysis to ethanol during the cellulose conversion.

Two-Step One-Pot Reductive Amination of Furanic Aldehydes Using CuAlOx Catalyst in a Flow Reactor.

Aminomethylhydroxymethylfuran derivatives are well known compounds which are used in the pharmaceutical industry. Reductive amination of 5-hydroxymethylfurfural (HMF) derived from available non-edible lignocellulosic biomass is an attractive method for the synthesis of this class of compounds. In the present study, the synthesis of N-substituted 5-(hydroxymethyl)-2-furfuryl amines and 5-(acetoxymethyl)-2-furfuryl amines was performed by two-step process, which includes the condensation of furanic aldehydes (HMF and 5-acetoxymethylfurfural) with primary amines in methanol on the first step and the reduction of obtained imines with hydrogen in a flow reactor over CuAlOx catalyst derived from layered double hydroxide on the second step. This process does not require isolation and purification of intermediate imines and can be used to synthesize a number of aminomethylhydroxymethylfurans in good to excellent yield.

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.

Investigating the interactions between lignocellulosic biomass and synthetic polymers during co-pyrolysis by simultaneous thermal and spectroscopic methods

The aim of this study was to investigate the effects of synthetic polymers during co-pyrolysis. To this end, a non-edible lignocellulosic biomass, walnut shells, and three synthetic polymers that were obtained from a recycling plant (PET, PS and PVC) were co-pyrolyzed in pairs using a thermogravimetric analysis (TGA) device coupled online with a mass spectrometer (MS) and an FT-IR spectrometer. The simultaneous usage of the combined techniques allowed collection of information about the pyrolysis and co-pyrolysis processes, as well as identification of the gases that evolved. During dynamic experiments, different heating rates were used and the characteristic temperatures, kinetic parameters, and evolved gases of co-pyrolysis of each pair of the materials were compared to those obtained from the pyrolysis of the individual materials. In order to calculate the activation energy and elucidate the reaction chemistry, four models which use iso-conversional approaches, namely Friedman, Kissinger–Akahira–Sunose, Starink, and Flynn–Wall–Ozawa, were applied to the TGA data and the same trends of results were observed in all models. The activation energy values of the pyrolysis and co-pyrolysis showed fluctuations related to the conversion points which indicated the complex nature of the samples, or interactions occurred during the process. Moreover, PET, PS, and PVC blending resulted in synergy with the biomass depending on the nature of the polymer, and volatile products including methyl, water, methoxy, carbon dioxide, water, benzene, acetaldehyde, styrene, and hydrochloric acid were monitored to obtain their evolution profiles related to decomposition range.

Significance and Challenges of Biomass as a Suitable Feedstock for Bioenergy and Biochemical Production: A Review

Fossil fuels have been a major contributor to greenhouse gases, the amounts of which could be reduced if biofuels such as bioethanol and biodiesel were used for transportation. One of the most promising biofuels is ethyl alcohol. In 2015, the world production of ethanol was 25.6 billion gallons and the USA, Brazil, China, the European Union, and 28 other countries have set targets for blending ethanol with gasoline. The two major bio-source materials used for ethanol production are corn and sugarcane. For 1st generation biofuels, sugarcane and corn feedstocks are not able to fulfill the current demand for alcohol. Non-edible lignocellulosic biomass is an alternative bio-source for creating 2nd generation biofuels and algae biomass for 3rd and 4th generation biofuels. This review discusses the significance of biomass for the different generations of biofuels, and biochemical and thermochemical processes, and the significance of biorefinery products.

Characterization of non-edible lignocellulosic biomass in terms of their candidacy towards alternative renewable fuels

Lignocellulosic biomass off late are considered as potential feedstock for biofuel production to meet the world energy demand. For designing the process to convert biomass into an alternative source of energy, it is essential to determine the characteristics of these lignocellulosic biomass. The aim of the present study is to determine the physicochemical characterization of selected non-edible and waste lignocellulosic biomass and utilization of these biomass in the best possible way for the production of fuels and chemicals. Physical and chemical characterization of lignocellulosic and waste biomass were carried out by thermogravimetric analysis (TGA), heating value, crystallinity index, CHNS/O analysis, FTIR, compositional analysis, EDX analysis, and extractives analysis. Further, XRF analysis was used to confirm the presence of inorganic elements in ash. TGA confirmed that maximum degradation (active pyrolytic zone) of these biomass occurred in the temperature range of 200–500 °C. These biomass were further characterized by finding out the structural constituents along with oil percentage and amount of mineral matters. The physical analysis confirmed that these biomass are suitable feedstock for pyrolysis due to the presence of lower amount of sulfur, nitrogen, moisture, and ash and higher amount of volatile matters. A higher percentage of extractives (30–57%) further reaffirmed that all these seeds could be utilized for producing fuels and valuable chemicals.

Using a low melting solvent mixture to extract value from wood biomass.

Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals.

Biodiesel production from non-edible lignocellulosic biomass of Cassia fistula L. fruit pulp using oleaginous yeast Rhodosporidium kratochvilovae HIMPA1

This study explored biodiesel production from a low cost, abundant, non-edible lignocellulosic biomass from aqueous extract of Cassia fistula L. (CAE) fruit pulp. The CAE was utilized as substrate for cultivating novel oleaginous yeast Rhodosporidium kratochvilovae HIMPA1. This oleaginous yeast accumulates high amount of triacylglycerides as large intracellular lipid droplets (4.35±0.54μm) using CAE as sole nutritional source. Total lipids (4.86±0.54g/l) with lipid content of 53.18% (w/w) were produced by R. kratochvilovae HIMPA1 on CAE. The FAME profile obtained revealed palmitic acid (C16:0) 43.06%, stearic acid (C18:0) 28.74%, and oleic acid (C18:1) 17.34% as major fatty acids. High saturated fatty acids content (72.58%) can be blended with high PUFA feedstocks to make it an industrially viable renewable energy product.

(Invited) Electrochemical Upgrading of Bio-Oil

Biomass is a potential renewable source for liquid fuels and most commodity chemicals. Non-edible lignocellulosic biomass residue such as agricultural and forest wastes can be converted to liquid fuels via bio-oil production by fast pyrolysis. A variety of challenges related to unwanted characteristics of bio-oil need to be overcome for practical use of this approach. One such challenge is the high oxygen content (35 – 40 wt%) of bio-oil. The conventional approach to remove oxygen is the hydro-deoxygenation process that uses high pressure hydrogen. Typical bio-oil is biphasic and only the organic phase is processed in subsequent upgrading steps, leaving behind valuable carbon-containing material in the aqueous phase. Ceramatec and its partners, Pacific Northwest National Laboratory (PNNL), Technology Holding LLC, and Drexel University, are investigating an electrochemical process to remove oxygen from bio-oil components without the use of hydrogen. Model compounds have been tested using an oxygen ion conducting ceramic membrane based electrochemical cells operated in the temperature range of 500 – 600 °C. Under an applied electric potential, only oxygen ions are transported through the membrane. In addition to direct removal of oxygen from the oxygenated hydrocarbons, indirect removal of oxygen via reaction with hydrogen that is generated by the electrolysis of steam present in the feed is also expected to aid in the electrodeoxygenation (EDox) process. Feasibility tests were performed using water soluble model compounds, guaiacol that has two oxygen containing functional groups, a phenolic (−OH) and methoxy (−OCH3) groups and syringol that has a phenolic and two methoxy groups. These compounds are produced by pyrolysis of lignin. The selected model compound is co-fed with steam without using external hydrogen in the feed. A button cell configuration was used as the test vehicle with a nickel-cermet cathode and a ferrite-cobaltite perovskite anode. The results show that the EDox process produces a variety of compounds that have lower or no oxygenated functional groups. The liquid products were analyzed using GC-MS. Analysis shows that, on weight basis, a reduction of 25% and 47% of oxygen content occurred for guaiacol and syringol feed. Gas phase hydrocarbon products such as methane, ethane, propane, and propene were also identified but not included in estimating oxygen removal. A deoxygenation trial of aqueous phase from the pyrolysis of yellow pine oil received from PNNL was also performed. Based on the analysis of liquid products collected, over 24% of oxygen removal was accomplished. Test system modifications are planned to allow complete mass balance of the process. Electrode materials and test conditions will be modified to evaluate the effect on oxygen removal and product selectivity. Acknowledgment: This material is based upon work supported by the Department of Energy under Award Number DE-EE0006288. Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Simultaneous saccharification and fermentation of enzyme pretreated Lantana camara using S. cerevisiae

Lantana camara, an abundantly available non-edible lignocellulosic biomass has been found to be a potential feedstock for ethanol production. The substrate was first pretreated with laccase followed by simultaneous saccharification and fermentation using cellulase and Saccharomyces cerevisiae, respectively. Laccase was produced from Pleurotus sp. and carbohydratases (cellulase and xylanase) were produced from Trichoderma reesei Rut C30. Using pretreated substrate simultaneous saccharification and fermentation was optimized through central composite design-based response surface methodology. Maximum bioethanol concentration of 5.14% (v/v) was obtained at optimum process conditions of substrate concentration 17% (w/v), inoculum volume 9% (v/v), inoculum age 60 and 144h of incubation time. To enhance ethanol yield, S. cerevisiae was treated with ethyl methane sulfonate, a chemical mutagenic agent which induced mutagenesis. A maximum bioethanol concentration of 6.01% (v/v) was obtained using the mutated strain of S. cerevisiae (CM5).

Direct rate constant for the reaction of OH radicals with the biofuel molecule ethyl levulinate

Second generation (2G) biofuels are produced from non-edible lignocellulosic biomass providing sustainable alternatives for fossil fuels. The OH reaction rate constant has been determined for the 2G biofuel ethyl levulinate (CH3C(O)CH2CH2C(O)OCH2CH3, ELA) (1) for the first time. The direct reaction kinetic technique of pulsed laser photolysis (PLP) coupled with resonance fluorescence (RF) detection of OH radicals has been used to determine the rate constant value of k 1 = (3.43 ± 0.36) × 10−12 cm3 molecule−1 s−1 (298 K), where the error given designates 2σ accuracy. Implications for atmospheric chemistry have been discussed.

Catalytic routes for the conversion of biomass into liquid hydrocarbon transportation fuels

Concerns about diminishing fossil fuel reserves along with global warming effects caused by increasing levels of CO2 in the atmosphere are driving society toward the search for new renewable sources of energy that can substitute for coal, natural gas and petroleum in the current energy system. Lignocellulosic biomass is abundant, and it has the potential to significantly displace petroleum in the production of fuels for the transportation sector. Ethanol, the main biomass-derived fuel used today, has benefited from production by a well-established technology and by partial compatibility with the current transportation infrastructure, leading to the domination of the world biofuel market. However, ethanol suffers from important limitations as a fuel (e.g., low energy density, high solubility in water) than can be overcome by designing strategies to convert non-edible lignocellulosic biomass into liquid hydrocarbon fuels (LHF) chemically similar to those currently used in internal combustion engines. The present review describes the main routes available to carry out such deep chemical transformation (e.g., gasification, pyrolysis, and aqueous-phase catalytic processing), with particular emphasis on those pathways involving aqueous-phase catalytic reactions. These latter catalytic routes achieve the required transformations in biomass-derived molecules with controlled chemistry and high yields, but require pretreatment/hydrolysis steps to overcome the recalcitrance of lignocellulose. To be economically viable, these aqueous-phase routes should be carried out with a small number of reactors and with minimum utilization of external fossil fuel-based hydrogen sources, as illustrated in the examples presented here.