Cheap Biomass Research Articles

In vitro reconstitution and characterisation of the oxidative d-xylose pathway for production of organic acids and alcohols

The oxidative d-xylose pathway, i.e. Dahms pathway, can be utilised to produce from cheap biomass raw material useful chemical intermediates. In vitro metabolic pathways offer a fast way to study the rate-limiting steps and find the most suitable enzymes for each reaction. We have constructed here in vitro multi-enzyme cascades leading from d-xylose or d-xylonolactone to ethylene glycol, glycolic acid and lactic acid, and use simple spectrophotometric assays for the read-out of the efficiency of these pathways. Based on our earlier results, we focussed particularly on the less studied xylonolactone ring opening (hydrolysis) reaction. The bacterial Caulobacter crescentus lactonase (Cc XylC), was shown to be a metal-dependent enzyme clearly improving the formation of d-xylonic acid at pH range from 6 to 8. The following dehydration reaction by the ILVD/EDD family d-xylonate dehydratase is a rate-limiting step in the pathway, and an effort was made to screen for novel enolase family d-xylonate dehydratases, however, no suitable replacing enzymes were found for this reaction. Concerning the oxidation of glycolaldehyde to glycolic acid, several enzyme candidates were also tested. Both Escherichia coli aldehyde dehydrogenase (Ec AldA) and Azospirillum brasilense α-ketoglutarate semialdehyde dehydrogenase (Ab AraE) proved to be suitable enzymes for this reaction.

Optimization of bonding parameters of laminated wood using a novel bio-based RPF adhesive

Adhesive is the key component and factor for the manufacture of glulam, affected both the properties and cost of glulam product. Bio-based resorcinol-phenol-formaldehyde (BRPF) resin was developed by partly replacing the expensive resorcinol and phenol with the cheap biomass derived pyrolysis oil. The press process parameters and the dosage of adhesive and corresponding curing agent were selected as the factors and extensively studied. BRPF resin was successfully used to bond the laminas to produce glulam, and the optimized process parameters for the cold-pressing adhesion of BRPF resin with pine wood were obtained as follows: the cold-pressing pressure 1.4 MPa, the cold-pressing time 9 h, the amount of adhesive coating 320 g/m2, and the proportion of curing agent (poly-formaldehyde) 17%. The mechanical performances of laminated wood bonding with BRPF resin under the optimal condition were further verified. It is believed that the results obtained here will promote the use of bio-based resin in the bonding of laminated wood, and then contribute to the green manufacturing of glulam with lower cost.

Sustainable activated carbons from dead ginkgo leaves for supercapacitor electrode active materials

The practical applications of some advanced carbon nanomaterials in supercapacitors are still hampered by the resource scarcity and high cost. It arouses great interest to seek for ample and low-cost substitutes to meet the need of upcoming large-scale productions. The chemical conversion of renewable and abundant biomass provides a good opportunity for the economic and sustainable synthesis of carbon based electrode materials. In this work, activated ginkgo leaf-derived carbons were investigated as porous cheap biomass carbons with utility as supercapacitor electrode materials in the acid electrolyte. The influences of KOH-, ZnCl2-, and H3BO3-activations on the composition, morphology and performance of as-prepared carbons were studied and discussed. Benefiting from the superior electrochemical activity endowed by the hierarchical nano-architecture and abundant oxygen-containing groups, the as-obtained KOH-activated ginkgo leaf-derived carbon material exhibited the best specific capacitance (374F g−1 at 0.5 A g−1) relative to pristine carbon, ZnCl2-, and H3BO3-activated carbons. And this KOH-activated ginkgo leaf-derived carbon in the two-electrode configuration also demonstrated satisfactory specific capacitance (272F g−1 at 0.2 A g−1) and cycling reliability. Moreover, these performances also outperform those of some similar carbon materials.

Microbial production of mannitol by Lactobacillus brevis 3-A5 from concentrated extract of Jerusalem artichoke tubers.

In the present study, the conversion of the extract of Jerusalem artichoke tubers for mannitol production by Lactobacillus brevis 3-A5 was investigated. When the bacterium utilized enzymatic hydrolysates of Jerusalem artichoke extract as the main substrates in batch fermentation, the significant decrease in mannitol productivity was observed when the initial concentration of reducing sugar increased. Then, a strategy of continuous fed-batch fermentation was adopted for improving mannitol production with enzymatic hydrolysates of Jerusalem artichoke extract as main substrates. Although the concentration of mannitol could reach 199.86 g/L at the end of the fermentation, the productivity for the overall process of the fermentation was only 1.67 g/L/H. To improve the mannitol productivity with both higher yield and concentration, the simultaneous enzymatic saccharification and fermentation (SSF) was studied. In SSF, the mannitol production reached 176.50 g/L in 28 H with a productivity of 6.30 g/L/H and a yield of 0.68 g/g total sugar. Our study provides a cost-effective and eco-friendly method for mannitol production from a cheap biomass.

NaCl Crystal Tuning Nitrogen Self-Doped Porous Graphitic Carbon Nanosheets for Efficient Oxygen Reduction

The demand on the highly efficient and low-cost cathodic electrocatalysts for commercialization of fuel cells is rapidly increasing. One smart route for obtaining these ideal electrocatalysts is extracting active carbon materials from natural and cheap biomass waste. Here, we prepared a novel nitrogen self-doped porous graphitic carbon nanosheets (NPGCNs-NaCl) derived from a nitrogen-rich pruning of Lycium barbarum L. using NaCl crystal as intercalation agent. The as-obtained NPGCNs-NaCl possessed porous structure, large surface area, increased content of nitrogen and high graphitic carbon, and thus making it with high electrocatalytic activity for oxygen reduction reaction (ORR). Most importantly, significantly enhanced stability and tolerance against methanol were observed compared with commercial Pt/C catalyst in alkaline solution. This work is believed to open a new avenue for manufacturing advanced and low-cost ORR electrocatalysts in fuel cells from biomass waste.

Study on the formation of direct reduced iron by using biomass as reductants of carbon containing pellets in RHF process

To investigate the possibility of using biomass reductants instead of fossil fuels in the formation of direct reduced iron (DRI) in rotary hearth furnace (RHF), three kinds of cheap biomass such as bamboo char, straw fiber and charcoal were selected as reductants to compare with anthracite and graphite. The effect of reductants, temperature, dwelling time, C/O ratio and particle sizes on the shrinkage, strength and metallization of the biomass/ore pellets was investigated and discussed. The optimized reduction conditions were obtained as 1200 °C, 20min, C/O = 0.7 and the particle size range of <0.15 mm, 1–2 mm and 0.15–0.3 mm for straw fiber, bamboo char and charcoal respectively. The results showed that straw fiber was considered as an optimal reductant in the formation of direct reduced iron instead of fossil fuels. By the techniques of scanning electron microscope (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD), the mechanism of biomass as reductants was revealed. Volatile matter was confirmed to play an important role in the formation of DRI when biomass used as reductants.

Bacterial-cellulose-derived interconnected meso-microporous carbon nanofiber networks as binder-free electrodes for high-performance supercapacitors

Abstract Bacterial cellulose (BC), a typical biomass prepared from the microbial fermentation process, has been proved that it can be an ideal platform for design of three-dimensional (3D) multifunctional nanomaterials in energy storage and conversion field. Here we developed a simple and general silica-assisted strategy for fabrication of interconnected 3D meso-microporous carbon nanofiber networks by confine nanospace pyrolysis of sustainable BC, which can be used as binder-free electrodes for high-performance supercapacitors. The synthesized carbon nanofibers exhibited the features of interconnected 3D networks architecture, large surface area (624 m2 g−1), mesopores-dominated hierarchical porosity, and high graphitization degree. The as-prepared electrode (CN-BC) displayed a maximum specific capacitance of 302 F g−1 at a current density of 0.5 A g−1, high-rate capability and good cyclicity in 6 M KOH electrolyte. This work, together with cost-effective preparation strategy to make high-value utilization of cheap biomass, should have significant implications in the green and mass-producible energy storage.

Numerical investigation of the staged gasification of wet wood

Gasification of wooden biomass makes it possible to utilize forestry wastes and agricultural residues for generation of heat and power in isolated small-scale power systems. In spite of the availability of a huge amount of cheap biomass, the implementation of the gasification process is impeded by formation of tar products and poor thermal stability of the process. These factors reduce the competitiveness of gasification as compared with alternative technologies. The use of staged technologies enables certain disadvantages of conventional processes to be avoided. One of the previously proposed staged processes is investigated in this paper. For this purpose, mathematical models were developed for individual stages of the process, such as pyrolysis, pyrolysis gas combustion, and semicoke gasification. The effect of controlling parameters on the efficiency of fuel conversion into combustible gases is studied numerically using these models. For the controlling parameter are selected heat inputted into a pyrolysis reactor, the excess of oxidizer during gas combustion, and the wood moisture content. The process efficiency criterion is the gasification chemical efficiency accounting for the input of external heat (used for fuel drying and pyrolysis). The generated regime diagrams represent the gasification efficiency as a function of controlling parameters. Modeling results demonstrate that an increase in the fraction of heat supplied from an external source can result in an adequate efficiency of the wood gasification through the use of steam generated during drying. There are regions where it is feasible to perform incomplete combustion of the pyrolysis gas prior to the gasification. The calculated chemical efficiency of the staged gasification is as high as 80–85%, which is 10–20% higher that in conventional single-stage processes.

Progress in chemicals production by microbial consortia

Using cheap biomass resources is a hotspot of research on industrial biotechnology. It is difficult for traditional fermentations with single strain to treat so complex components and more impurities, which becomes the key problem in industrialization. In this review, some existing industrial bioprocesses involving microbial consortia were described. Comparison of 1,3-propanediol production by microbial consortia and pure cultures were then introduced and the relationship between cells in microbial consortia were summarized. Finally, the perspective was also addressed to design and apply microbial consortia in the future.

Impact of the Temperature of Waste Biomass Py-Rolysis on the Quality of the Obtained Biochar

Abstract Combustion and co-combustion of biomass from different sources is one of the most popular technologies applied in Poland. It allows management of numerous industrial, communal and agricultural waste. Organic waste constitutes one of the richest sources of cheap biomass solid fuels since they are very popular. The paper includes an assessment of practical use of biomass waste: hazelnut shell and pistachio nut shell. The impact of pyrolysis temperature (300, 450 and 550°C) of the investigated biomass on the quality of the obtained biochar was determined and the optimal temperature of this process was defined. The quality of the investigated biomass was analysed on account of its use for energy purposes. Numerous advantageous properties of the obtained materials were found out, for instance: low content of ash and a noticeable increase of the calorific value with an increase of the pyrolysis temperature.

Facile synthesis of novel hierarchically porous carbon derived from nature biomass for enhanced removal of NaCl.

In this work, the hierarchically porous biomass carbon (HPBC) was originally prepared for desalination through a simple activation of cheap biomass carbon (BC). Such crucial activated conditions as the KOH/C ratio, the activation time and the activation temperature were deeply investigated. It is demonstrated that the activated conditions had a great influence on the structure properties and electrochemical performance. According to structure and surface analyses, the HPBC with larger surface area and hierarchical porous structure could be well obtained in suitable activation conditions. The electrochemical analyses showed that the HPBC showed increased electrosorption capacitance, lower inner resistance and good stability, which can be attributed to large accessible surface area and smooth ion transportation. In the further desalination test, the HPBC electrode exhibited enhanced desalination efficiency and capacity. Hence, HPBC can be a promising candidate electrode material for desalination with low cost and high efficiency.

Eco-efficient biorefineries: Techno-fix for resource constraints?

An eco-efficient bioeconomy has been widely promoted to alleviate resource constraints of rising global demand. An integrated, diversified biorefinery would convert diverse non-food biomass into valuable products, thus providing input-substitutes for fossil fuels within current infrastructures. This agenda intensifies various resource burdens and market competition to supply cheap biomass. Biorefinery innovation trajectories have the same drivers as the current production-consumption patterns expanding global demand for food, feed, fuel, etc. More efficient, flexible conversion of biomass will strengthen financial incentives to intensify resource extraction, especially by industrialising agri-forestry systems. Such a techno-fix depends on cheapening resource supplies without paying for their societal and environmental costs.

Bacterial Cellulose: A Robust Platform for Design of Three Dimensional Carbon-Based Functional Nanomaterials.

Three dimensional (3D) carbon nanomaterials exhibit great application potential in environmental protection, electrochemical energy storage and conversion, catalysis, polymer science, and advanced sensors fields. Current methods for preparing 3D carbon nanomaterials, for example, carbonization of organogels, chemical vapor deposition, and self-assembly of nanocarbon building blocks, inevitably involve some drawbacks, such as expensive and toxic precursors, complex equipment and technological requirements, and low production ability. From the viewpoint of practical application, it is highly desirable to develop a simple, cheap, and environmentally friendly way for fabricating 3D carbon nanomaterials in large scale. On the other hand, in order to extend the application scope and improve the performance of 3D carbon nanomaterials, we should explore efficient strategies to prepare diverse functional nanomaterials based on their 3D carbon structure. Recently, many researchers tend to fabricate high-performance 3D carbon-based nanomaterials from biomass, which is low cost, easy to obtain, and nontoxic to humans. Bacterial cellulose (BC), a typical biomass material, has long been used as the raw material of nata-de-coco (an indigenous dessert food of the Philippines). It consists of a polysaccharide with a β-1,4-glycosidic linkage and has a interconnected 3D porous network structure. Interestingly, the network is made up of a random assembly of cellulose nanofibers, which have a high aspect ratio with a diameter of 20-100 nm. As a result, BC has a high specific surface area. Additionally, BC hydrogels can be produced on an industrial scale via a microbial fermentation process at a very low price. Thus, it can be an ideal platform for design of 3D carbon-based functional nanomaterials. Before our work, no systematic work and summary on this topic had been reported. This Account presents the concepts and strategies of our studies on BC in the past few years, that is, converting cheap biomass into high value-added 3D carbon nanomaterials and designing diverse functional materials on 3D carbon structure. We first briefly introduce the history, constituent, and microstructure features of BC and discuss its advantages as a raw material for preparing the CNF aerogels. Then, we summarize the methods and strategies for preparing various 3D carbon-based nanomaterials from BC. In addition, the potential applications of the developed CNF aerogel based functional materials are also highlighted in this Account, including stretchable conductors, oxygen reduction reaction catalysts, supercapacitors, lithium-ion battery, and oil cleanup. Finally, we give some prospects on the future challenges in this emerging research area of designing CNF aerogel based functional nanomaterials from BC.

A kinetic study on the Novozyme 435-catalyzed esterification of free fatty acids with octanol to produce octyl esters.

Octyl esters can serve as an important class of biolubricant components replacing their mineral oil counterparts. The purpose of the current work was to investigate the enzymatic esterification reaction of free fatty acids (FFA, from waste cooking oil) with octanol in a solvent-free system using a commercial lipase Novozyme 435. It was found that the esterificaton reaction followed the Ping-pong bi-bi kinetics with no inhibition by substrates or products within the studied concentration range. The maximum reaction rate was estimated to be 0.041 mol L(-1) g(-1) h(-1) . Additionally, the stability of Novozyme 435 in the current reaction system was studied by determining its activity and final conversion of FFA to esters after 12 successive utilizations. Novozyme 435 exhibited almost 100% enzyme activity up to 7 cycles of reaction and gradually decreased (by 5%) thereafter. The kinetic parameters evaluated from the study shall assist in the design of reactors for large-scale production of octyl esters from a cheap biomass source. The enzyme reusability data can further facilitate mass production by curtailing the cost of expensive enzyme consumption.

Modular design of metabolic network for robust production of n-butanol from galactose–glucose mixtures

BackgroundRefactoring microorganisms for efficient production of advanced biofuel such as n-butanol from a mixture of sugars in the cheap feedstock is a prerequisite to achieve economic feasibility in biorefinery. However, production of biofuel from inedible and cheap feedstock is highly challenging due to the slower utilization of biomass-driven sugars, arising from complex assimilation pathway, difficulties in amplification of biosynthetic pathways for heterologous metabolite, and redox imbalance caused by consuming intracellular reducing power to produce quite reduced biofuel. Even with these problems, the microorganisms should show robust production of biofuel to obtain industrial feasibility. Thus, refactoring microorganisms for efficient conversion is highly desirable in biofuel production.ResultsIn this study, we engineered robust Escherichia coli to accomplish high production of n-butanol from galactose–glucose mixtures via the design of modular pathway, an efficient and systematic way, to reconstruct the entire metabolic pathway with many target genes. Three modular pathways designed using the predictable genetic elements were assembled for efficient galactose utilization, n-butanol production, and redox re-balancing to robustly produce n-butanol from a sugar mixture of galactose and glucose. Specifically, the engineered strain showed dramatically increased n-butanol production (3.3-fold increased to 6.2 g/L after 48-h fermentation) compared to the parental strain (1.9 g/L) in galactose-supplemented medium. Moreover, fermentation with mixtures of galactose and glucose at various ratios from 2:1 to 1:2 confirmed that our engineered strain was able to robustly produce n-butanol regardless of sugar composition with simultaneous utilization of galactose and glucose.ConclusionsCollectively, modular pathway engineering of metabolic network can be an effective approach in strain development for optimal biofuel production with cost-effective fermentable sugars. To the best of our knowledge, this study demonstrated the first and highest n-butanol production from galactose in E. coli. Moreover, robust production of n-butanol with sugar mixtures with variable composition would facilitate the economic feasibility of the microbial process using a mixture of sugars from cheap biomass in the near future.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0327-7) contains supplementary material, which is available to authorized users.

(Invited) Microwave Chemistry Enabled Controlled Fabrication of Graphene with Tailored Structures for Designed Applications

Due to its excellent electronic, optical, thermal and mechanical properties, and its large surface area and low mass, graphene holds great potential for a wide range of applications. It seems that the research in graphene has now proceeded from the initial phase of developing myriad strategies for the synthesis of graphene sheets to the use of graphene in various research fields. Mass production of reduced graphene oxide and graphene nanoplatets has recently been achieved. However, it is still challengingto controllably produce solution processable highly conductive graphene sheets in large quantity, at low cost, via eco-friendly and energy saving process, with optimal sheet size, layer thickness, defective (vacancies and holes) and molecular structures (oxygen containing groups and non-defective graphene domains). All these structural parameters determine their electronic, thermal and mechanical properties of graphene, which are the key warrants for their practical application in various devices. As examples, fundamental studies and high-frequency electronics require pristine graphene. However, “bulk” applications such as flexible macroelectronics, and mechanically and electronically reinforced composites, require large quantities of solution-processible highly conductive large graphene sheets manufactured at low cost. On the other hand, holey graphene, referred to graphene with nanoholes in their basal plane, demonstrates much better performance in their application as metal free catalysts and in energy storage. Finally, there is a surge of interests in nanosized graphene sheets for solar cells and various biological applications due to their unique size effects, edge effects, and even quantum confinement effects. Most importantly, most of the commercial available solution processible graphene sheets were fabricated via a long multiple- step process (several hours to 5 days). By exploiting the unique thermal and kinetic effects induced by microwave heating and the right selection of graphite oxidation chemistry, we developed series of quick and scalable strategies to produce a family of “clean” graphene sheets (without surfactants and without metal ions and/or toxic residues) with controlled porous structures, and controlled sizes from a few nanometers to tens of micrometers. By choosing a series of cheap biomass molecules, also with the help of microwave heating, bottom-up fabrication approaches are developed to produce heteroatom (N, B and/or P) doped graphene sheets and graphene quantum dots with bright emission. The applications of these graphene sheets and graphene quantum dots in Lithium battery, metal free-catalysts, and multifunctional drug delivery will be discussed.

Production of monoclonal antibodies in plants for cancer immunotherapy.

Plants are considered as an alternative platform for recombinant monoclonal antibody (mAb) production due to the improvement and diversification of transgenic techniques. The diversity of plant species offers a multitude of possibilities for the valorization of genetic resources. Moreover, plants can be propagated indefinitely, providing cheap biomass production on a large scale in controlled conditions. Thus, recent studies have shown the successful development of plant systems for the production of mAbs for cancer immunotherapy. However, their several limitations have to be resolved for efficient antibody production in plants.

Recombinant biosynthesis of functional human growth hormone and coagulation factor IX in transgenic soybean seeds

Background Plants constitute promising systems for the alternative production of valuable recombinant proteins. Recently, ELELYSOTM, an enzymatic drug developed by the Israeli company Protalix Biotherapeutics to treat Type 1 Gaucher’s disease, became the first plant-derived therapeutic product to reach marketable status [1]. This confirms the inherent potential of plant systems for the large-scale production of pharmaceuticals and industrial proteins with high quality and at competitive costs. Soybeans [Glycine max (L.) Merrill] provide a potential economically viable platform for the large-scale production of different therapeutic molecules. Plant seeds are specialized in the stable accumulation of proteins at high levels, representing an excellent source of abundant and cheap biomass. Additionally, the vegetative growth of plants can be significantly extended under a daily photoperiod of 23 h of light, inducing more than a tenfold increase in seed production when compared with plants cultivated under field conditions [2]. In this report we present the recombinant biosynthesis and the molecular and functional characterization of two important therapeutic proteins in transgenic soybean seeds: the 22 kDa human growth hormone (hGH) and the 56 kDa human coagulation factor IX (hFIX), a vitamin K-dependent serine-protease glycoprotein utilized to treat Type B Christmas disease, the second most frequent haemophilia variant [3,4].

A route from olive oil production to natural dyeing: valorisation of prina (crude olive cake) as a novel dye source

An attempt has been made to valorise an agroindustrial solid waste in natural textile dyeing as a novel dye source. The dyeing and fastness properties of prina (crude olive cake/pomace) extract were evaluated to fill the gap in this field. This very cheap biomass was utilised (80 g/l) by applying chemical solvent‐free aqueous extraction to dye wool fabric with only small amounts (0.2, 0.4, 0.8, and 1.6 g/l) of metallic mordants, namely alum, iron(II) sulfate, copper(II) sulfate, stannous chloride, and potassium dichromate, and avoiding the use of alkali, acid, chemicals, and auxiliaries in dyeing and washing processes. Colour shades of beige, cream, sandy, apricot, straw, cumin, mustard, olive, and khaki were obtained. Significant differences in colour strength and CIELab coordinates were observed, depending on mordant type and mordanting method. Copper(II) sulfate and iron(II) sulfate ensured the most significant colour changes and nuances, the darkest colours, and the best light fastness values. Prina extract itself (without mordant) has a light fastness of 3 (fair) and excellent wash fastness of 4–5, both for colour change and bleeding. Irrespective of the concentration and mordanting method, alum, stannous chloride, and potassium dichromate did not generate a light fastness improvement compared with the control sample. Although good light and wash fastness values have been achieved without mordants, it is necessary to use them to widen the colour gamut and to obtain increased colour strength.

Microorganism lipid droplets and biofuel development

Lipid droplet (LD) is a cellular organelle that stores neutral lipids as a source of energy and carbon. However, recent research has emerged that the organelle is involved in lipid synthesis, transportation, and metabolism, as well as mediating cellular protein storage and degradation. With the exception of multi-cellular organisms, some unicellular microorganisms have been observed to contain LDs. The organelle has been isolated and characterized from numerous organisms. Triacylglycerol (TAG) accumulation in LDs can be in excess of 50% of the dry weight in some microorganisms, and a maximum of 87% in some instances. These microorganisms include eukaryotes such as yeast and green algae as well as prokaryotes such as bacteria. Some organisms obtain carbon from CO2 via photosynthesis, while the majority utilizes carbon from various types of biomass. Therefore, high TAG content generated by utilizing waste or cheap biomass, coupled with an efficient conversion rate, present these organisms as bio-tech ‘factories’ to produce biodiesel. This review summarizes LD research in these organisms and provides useful information for further LD biological research and microorganism biodiesel development. [BMB Reports 2013; 46(12): 575-581]