Biomass Suspension Research Articles

Biomass suspension catalysed the generation of various alkyl esters from acid oil and virgin cottonseed oil

A substantial reduction in the cost of biodiesel production necessitates the identification of less expensive lipid-bearing substrates and a cost-effective process. The present study demonstrates the use of biomass suspension of Aspergillus sps. as a whole-cell catalyst for the generation of various alkyl esters from acid oil and cottonseed oil with different alcohols (methanol to decanol) as acyl acceptors. The yield of alkyl esters increased from methanol (79%) to pentanol (87%), followed by a decrease from hexanol (80%) to decanol (55%) in the case of acid oil. The extent of transesterification was significantly higher [P < 0.05] in case of acid oil, with most of the acyl acceptors as compared to cottonseed oil. The study reveals the potential use of biomass suspension of fungus as a catalyst and acid oil as an alternative, low-cost bearing, and quality feedstock for the generation of biodiesel for a diverse variety of industrial/commercial use.

A Thermosiphon Photobioreactor for Photofermentative Hydrogen Production by Rhodopseudomonas palustris.

A thermosiphon photobioreactor (TPBR) can potentially be used for biohydrogen production, circumventing the requirement for external mixing energy inputs. In this study, a TPBR is evaluated for photofermentative hydrogen production by Rhodopseudomonas palustris (R. palustris). Experiments were conducted in a TPBR, and response surface methodology (RSM), varying biomass concentration, and light intensity and temperature were employed to determine the operating conditions for the enhancement of both hydrogen production as well as biomass suspension. Biomass concentration was found to have had the most pronounced effect on both hydrogen production as well as biomass suspension. RSM models predicted maximum specific hydrogen production rates of 0.17 mol m−3h−1 and 0.21 mmol gCDW−1h−1 at R. palustris concentrations of 1.21 and 0.4 g L−1, respectively. The experimentally measured hydrogen yield was in the range of 45 to 77% (±3.8%), and the glycerol consumption was 8 to 19% (±0.48). At a biomass concentration of 0.40 g L−1, the highest percentage of biomass (72.3%), was predicted to remain in suspension in the TPBR. Collectively, the proposed novel photobioreactor was shown to produce hydrogen as well as passively circulate biomass.

Heat transfer and chemical kinetics analysis of a novel solar reactor for hydrothermal processing

This work proposes a novel concept of a hydrothermal solar reactor to convert biomass waste efficiently into bio-products. The operation of this system is studied using heat transfer and kinetic models to assess the concept’s capabilities. The reactor consists of a cylindrical cavity with a window that allows concentrated solar radiation to pass. Inside the cavity, radiative energy is absorbed by an array of tubes, where the reacting water biomass suspension circulates. The cavity walls are assumed to be highly reflecting, and the tube walls to be highly absorbing. Highly-scattering inert fluidized particles are utilized in the cavity to redistribute radiation prior to absorption by the tubes. The cavity-type solar reactor design aims at homogenizing the distribution of radiation absorbed by the tubes, that is, to minimize axial and angular thermal gradients and reduce thermal stresses, given the high operating pressures required for hydrothermal processes. The Monte Carlo Method (MCM) for thermal radiative transfer is used to couple the solar radiation absorption to conduction and convection heat transfer phenomena. The effect of design parameters, like the number of tubes, their location, the relative size of the cavity, and the scattering particles concentration, is evaluated in the reactor thermal performance. The results indicate that adding the participating medium and carefully choosing the number and distribution of tubes allows reactor thermal efficiencies above 80% while reducing thermal gradients within the tubes. Moreover, the analysis shows the solar reactor concept can attain biogas and biocrude yields slightly above 20% and 30%, respectively.

High density cultivation and CO2 uptake by panel arrays of the macrophytic red alga Gracilaria vermiculophylla in a 100 L raceway pond

New approaches are needed for land-based cultivation of macrophytic red algae that reduce costly aeration requirements for biomass suspension and enable high-density cultivation. The goal of this study was to demonstrate the high-density cultivation of the carbohydrate-rich macrophytic red alga Gracilaria vermiculophylla on vertical arrays of panels deployed in an open channel raceway configuration similar to those developed for mass cultivation of microalgae. A clonal culture of G. vermiculophylla, consisting of branched, cylindrical thallus tissues of 8–10 cm length, was mechanically blended using a Waring blender into 2–3 cm fragments and then fluidically injected onto a 3 mm polypropylene mesh support. Immobilized G. vermiculophylla mesh panels were spaced 6.5 cm apart and aligned parallel to flowing seawater medium at nominal bulk velocity of 20 cm s−1 in a 100 L raceway pond of 20 cm liquid depth. This raceway was equipped with real-time measurement of CO2 concentration in the inlet and outlet gas for determination of CO2 uptake dynamics. Specific rates for CO2 uptake became saturated at 8000 ppm CO2. To match CO2 demand by the biomass under nutrient-replete conditions at 21 °C, the inlet gas CO2 was increased from 1000 to 4000 ppm (day 7–14), and then to 8000 ppm (day 14–23) at 0.010 L gas L−1 liquid min−1 gas flow. Over the 23 day cultivation, biomass on the panel increased by a factor of 48, with final biomass loading exceeding 10 kg FW m−2 panel area, and cumulative CO2 capture of 65%. The cumulative average areal productivity within the panel zone of the raceway exceeded 60 g AFDW m−2 day−1, and final biomass density nearing 7.2 g AFDW L−1 (47 g FW L−1) was achieved after 23 days. Overall, these outcomes demonstrate the potential for land-based raceway cultivation of clonal red macroalgae of present and future commercial significance.

Plant growth biostimulant activity of the green microalga Desmodesmus subspicatus

The plant biostimulant activity of the green microalga Desmodesmus subspicatus was investigated, focusing on its potential application to organic crops. Different concentrations of D. subspicatus biomass suspensions were applied to tomato seedlings (Solanum lycopersicum) via a foliar spray. The treatments promoted root growth and foliar area, which increased when the suspension was applied at concentrations of 1 g L−1 and 0.4 g L−1, respectively. To elucidate the major constituents responsible for this potential activity, the biomass of D. subspicatus was submitted to aqueous extraction and dialysis (1 kDa cut-off), giving rise to the non-dialyzable fraction E (12.3%). Size-exclusion chromatography performed on fraction E using a Bio-Gel P-2 column yielded six subfractions. Gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR) analyses of the E subfractions revealed the presence of glycosides as major constituents (approx. 81%), including one acidic glycoside, [6-sulfo-α-D-quinovopyranosyl-(1→1)-glycerol], and two neutral galactosyl glycosides, [α-D-galactopyranosyl-(1→6)-β-D-galactopyranosyl-(1→1)-glycerol] and [β-D-galactopyranosyl-(1→1)-glycerol]. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) analyses of fraction E resulted in the identification of the phytohormone zeatin (35 μg g−1). To evaluate the biostimulant potential of fraction E, different concentrations (0.5, 1.0, 1.5, and 2.0 g L−1) were tested for their effects on tomato seed germination, hypocotyl volume, and length. All tested concentrations induced increased hypocotyl lengths and volumes compared with standard treatment (water), at rates equivalent to those in response to a commercial product derived from Ascophyllum nodosum brown seaweed. These results indicated that the biomass suspension and aqueous extract of D. subspicatus showed plant growth biostimulant activity. Glycosides, together with zeatin, may play important roles in biostimulant activity.

Isolation of poly(3-hydroxybutyrate) from bacterial biomass using soap made of waste cooking oil

The aim of this work was to develop a soap-based method for the isolation of poly(3-hydroxybutyrate) from bacterial biomass. The method consisted of adding soap derived from waste cooking oil to a concentrated (25%) biomass suspension, heating and centrifugal separation. Purity above 95% could be achieved with soap:cell dry mass ratios at least 0.125 g/g, making the method comparable to other surfactant-based protocols. Molecular weights Mw of products from all experiments were between 350 and 450 kDa, being high enough for future material applications. Addition of hydrochloric acid to the wastewater led to the precipitation of soap and part of non-P3HB cell mass. The resulting precipitate was utilized as a carbon source in biomass production and increased substrate-to-P3HB conversion.

Numerical and Experimental Biomass Separation from Fermentation Process by Minihydrocyclones

AbstractBiomass particle separation is challenging in the pharmaceutical industry because of the smallness and lightness of such particles. Centrifugation is applied conventionally for batch separation. However, imposing multiple wash steps in order to eliminate culture residues and the high risk of extrinsic contamination hamper batch techniques. In this research, minihydrocyclones were introduced to provide a better solution for the mentioned limitations in continuous processes. Numerical separation of methylotrophic yeast from fermentation broth was carried out in three hydrocyclones with different lengths, and the most efficient one was examined experimentally. Three various feed flow rates and seven feed concentrations were evaluated. The concentration of biomass suspension in the product was raised to 20 %.

Purification and characterization of a noble thermostable algal starch liquefying alpha-amylase from Aeribacillus pallidus BTPS-2 isolated from geothermal spring of Nepal

A thermophilic strain, Aeribacillus pallidus BTPS-2 was isolated from Bhurung geothermal spring of Nepal. The 16 s rRNA sequence showed 99.8 % similarity with the type strain Aeribacillus pallidus DSM 3670. The morphological, physiological and biochemical properties were similar to the type strain. Alpha-amylase from A. pallidus BTPS-2 was purified to 19-fold purification by DEAE-Cellulose ion exchange chromatography. The Km value of amylase on starch was 0.51 ± 0.05 mg/mL. The optimum pH and temperature were 7.0 and 70 °C. SDS-PAGE analysis showed a single band at 100 kDa. The half-life of the enzyme at 80 °C was 2.81 h. The enzyme showed an inhibitory effect in the presence of Fe2+, Pb2+, Sn2+ and Hg2+ at 10 mM concentrations. TLC analysis showed that the enzyme is a liquifying alpha-amylase. The enzyme reduced the viscosity of algal biomass suspension up to 74.2 ± 0.17 % which was more efficient than Bacillus amyloliquefaciens alpha-amylase (80.5 ± 0.2 %).

Development in biomass preparation for suspension firing towards higher biomass shares and better boiler performance and fuel rangeability

Suspension-firing enjoys the great popularity in biomass-fired heat and power generation. Since it has the strictest requirement on fuel quality and particle size, cares must be taken in biomass handling. This paper reviews, combined with concrete cases, the development in biomass preparation methods for suspension-firing: the processes and their impacts on critical issues in biomass suspension-firing. The first-generation preparation method, based on raw biomass, was successfully used for biomass suspension co-firing at low shares and nowadays is mainly used for other combustion technologies, due to the large particles it produces. The second-generation method, based on biopellets, is commonly used in existing suspension-firing plants. It can reduce biomass particle size to 85% < 1 mm (maximum 3 mm), ensuring good ignition and particle burnout. 100% biomass suspension-firing is mainly for high-quality biomass and often uses additives to mitigate corrosion. To improve fuel rangeability, the third-generation method will be prevailing. It includes extra thermal pre-treatment for increasing the energy density and grindability of the feedstock. Suspension-firing trials of torrefied biopellets are performed at several power plants. It is too costly in the present energy market and can be promoted by a future regulatory condition change in favor of alternative solid fuel sources.

Endobacterial symbiont of Fusarium oxysporum f.sp. cubense and the pathogenicity of their symbiosis towards banana plantling

Fusarium oxysporum f.sp. cubense (Foc), a causal agent of panama disease was reported carrying bacterial endosymbionts. This research aimed to identify the endobacteria in 7 Foc strains and to study their symbiosis effect on the Foc pathogenicity towards Ambon Kuning and Tanduk banana cultivars. The pathogenicity of endobacteria-Foc symbiosis were tested in vitro on banana plantling. Crude filtrate and biomass suspension that were produced by culturing each Foc strains for 21 days in static condition either in PDB (Potato Dextrose Broth) (Foc − ) or in antibiotics supplemented PDB (Foc +) were used as effectors. The Foc pathogenicity was stated as disease severity percentage on leaves and on rhizome. The result showed that all Foc strains contained endobacteria. Enterobacter sp. was hosted by Foc IPBCC 19.1427 and Izhakiella australiensis was in the hyphae of Foc IPBCC 19.1430. Enterobacter sp. affected Foc IPBCC 19.1427 virulence towards banana cv. Tanduk through effectors in the filtrate, while that towards cv. Ambon Kuning was unclear. Izhakiella australiensis did not affect Foc IPBCC 19.1430 virulence towards the two banana cultivars. The pathogenicity of Foc should further be verified, as the antibiotics given could not completely kill the endobacteria.

Impact on performance and emissions of the aspiration of algal biomass suspensions in the intake air of a direct injection diesel engine

Recently, the production of sustainable biofuels from algal biomass has gained significant attention and been investigated as a potential replacement of fossil fuel. However, existing downstream processes for producing biodiesel from algae cells are complex, highly energy-intensive, and have high economic and environmental cost. Therefore, this work introduces an alternative and novel method of utilizing the energy content of microalgae that precludes lipid extraction by aspirating wet algal biomass suspensions directly into the intake air of an internal combustion engine.For all engine experiments, powdered algae cells were prepared as slurries at different biomass concentrations. The impacts of (i) varying the biomass concentration with constant suspension injection flowrate into the engine intake and (ii) varying suspension injection flowrate with constant biomass concentration were investigated.A correlation between engine work produced during combustion and algal biomass aspiration was found. At constant flowrate and greater than 5% biomass concentrations, an increase of energy release during combustion from the aspirated algae could be observed. However, the aspiration of low concentration biomass suspension produced a negative impact on engine performance relative to water-only aspiration. The engine exhaust gas of nitrogen oxides (NOx) was reduced for all algae suspension tests relative to diesel-only combustion. However, the carbon monoxide (CO) emission level was much higher relative to diesel-only tests at high biomass concentrations and injection flowrate.These findings demonstrate the possibility of utilising the energy content of algal biomass in combustion without lipid extraction, with added benefits of reducing NOx emissions.

Membrane fouling caused by lipopolysaccharides: A suggestion for alternative model polysaccharides for MBR fouling research

Polysaccharides were identified as key foulants in membrane bioreactors (MBRs) in previous studies. Polysaccharides used for MBR fouling research should represent real foulants, and alginate and dextran have often been used as model polysaccharides. However, their properties are not necessarily similar to those of polysaccharides that actually cause membrane fouling in MBRs. In recent studies, it was shown that polysaccharides causing membrane fouling in MBRs had the structures of lipopolysaccharides (LPSs), which are components of the cell wall of gram-negative bacteria. In the present study, therefore, membrane fouling caused by commercially available LPSs was investigated and was compared with that caused by model polysaccharides. In a series of batch filtration tests using four different microfiltration (MF) and ultrafiltration (UF) membranes, regardless of the membrane used, LPSs caused more severe membrane fouling than did alginate or dextran when they were filtered under the condition of the same organic carbon concentration. The properties of LPSs were found to be considerably different from those of alginate and dextran. In particular, affinity of LPS to PVDF polymer assessed by quartz crystal microbalance (QCM) mass measurement was remarkably high, and it would account for the severe fouling caused by LPSs. In experiments with filtering of mixtures of the model polysaccharides and a biomass suspension collected from a pilot-scale MBR, which were conducted to mimic the sudden increase in dissolved polysaccharides in real MBRs, LPS induced significant irreversible fouling, while alginate and dextran did not. The results obtained in this study clearly demonstrated high fouling potential of LPSs. Use of LPSs in future MBR fouling studies is therefore recommended.

Publisher's Note: “Experimental and numerical study of the characteristics of biomass suspension combustion in a hot-water boiler” [J. Renewable Sustainable Energy 10, 033103 (2017)

Publisher's Note: “Experimental and numerical study of the characteristics of biomass suspension combustion in a hot-water boiler” [J. Renewable Sustainable Energy <b>10</b>, 033103 (2017)

HYPOGLYCEMIC AND HYPOLIPIDEMIC EFFECTS OF SPIRULINA PLATENSIS, PHYCOCYANIN, PHYCOCYANOPEPTIDE AND PHYCOCYANOBILIN ON MALE DIABETIC RATS

This study aimed to evaluate hypoglycemic and hypolipidemic activities of Spirulina Platensis and its bioactive components (phycocyanin (PC), phycocyanopeptide (PCP) and phycocyanobilin (PCB)) on male diabetic Rats compared to controls and glibenclamide drug. For this reason, male Albino rats were equally divided into seven groups designated as normal control, diabetic control, diabetic + glibenclamide (Glyburide) drug (600 µg kg−1 body weight), diabetic + Spirulina biomass suspension (50 mg/ml/ kg−1 body weight), diabetic + phycocyanin (50 mg kg−1 body weight), diabetic + phycocyanopeptide (49 mg kg−1 body weight) and diabetic + phycocyanobilin (982 µg kg−1 body weight). The results show a statistically significant reduction (P < 0.05) level of fasting blood glucose, insulin resistance and lipids levels in diabetic animals administration with Spirulina Platensis, phycocyanin, phycocyanopeptide and phycocyanobilin compared with diabetic control. Also, there were an increase in HDL–cholesterol levels and β-cell function in these treatments. Histopathologically, diabetic rats treated with spirulina, PC, PCP induced a slight improve of pancreatic cells and an obvious recovery of pancreatic cells. The expression of insulin secretion from cells (β-cells) of diabetic rats was improved in the groups treated with Spirulina, phycocyanin, phycocyanopeptide. While, diabetic rats treated with phycocyanobilin recorded insulin levels lower than them. From this study it can be concluded that Spirulina Platensis, phycocyanin, phycocyanopeptide and phycocyanobilin possessed hypoglycemic, insulin sensitivity and hypolipidemic effects. Hypoglycemic and hypolipidemic effects of Spirulina Platensis may be attributed to phenolic compounds and phycocyanin. The antidiabetic effect of PC is most likely due to its ability to reduction of insulin resistance, enhance β-cell function and recovery of β-cells. The effect of PC may be attributed to selenium-binding phycocyanopeptide or/ and phycocyanobilin responsible for the antioxidant activity and chromium-binding phycocyanopeptide which activates insulin receptors.

Experimental and numerical study of the characteristics of biomass suspension combustion in a hot-water boiler

Biomass powder fuel is an abundant and widely available biomass resource with potential advantages including simple manufacturing process, low energy consumption during processing, high bulk density, convenient storage and transport and high combustion efficiency over other forms of biomass fuels such as bulk, compact block and grain fuels. However, the nature of biomass powder produces a series of issues during combustion including inferior combustion stability, which demands a deep investigation to enhance the energy production and utilization from powder biomass. In this paper, a combined experimental and theoretical study on combustion characteristics is carried out based on a recently developed biomass suspension hot-water boiler with a new design. When the fuel powder concentration is 450 g/m3 and the primary/secondary air ratio is 0.8, the biomass suspension combustion hot-water boiler reaches its optimal condition and the combustion chamber temperature and the thermal efficiency are at their highest levels. The thermal performance of the designed biomass suspension hot-water boiler is tested for the rated condition. Data show that the combustion efficiency and the thermal efficiency reach 97% and 83%, respectively, whereas the harmful gas (CO, SO2, NOx) content in the fumes meet the requirements of the national industrial boiler atmospheric pollutant emission standard in China. The computational fluid dynamics simulation of the temperature field in the furnace shows that combustion of a biomass powder fuel in a pre-combustion chamber and a furnace is not only closely related to the oxygen supply but also related to the airflow ratio and the furnace temperature. The simulated results show that the furnace temperature field, the primary and secondary airflow streamlines, the biomass powder grain movement trajectory and the component field distribution are in agreement with the experimental results. Our findings may help to design an efficient biomass suspension hot-water boiler.

A mathematical model for the effects of volume fraction and fiber aspect ratio of biomass mixture during enzymatic hydrolysis

Renewable energy or biofuel from lignocellulosic biomass is an alternative way to replace the depleting fossil fuels. The production cost can be reduced by increasing the concentration of biomass particles. However, lignocellulosic biomass is a suspension of natural fibres, and processing at high solid concentration is a challenging task. Thus, understanding the factors that affect the rheology of biomass suspension is crucial in order to maximize the production at a minimum cost. Our aim was to develop a mathematical model for enzymatic hydrolysis of cellulose by combining three scales: the macroscopic flow field, the mesoscopic particle orientation, and the microscopic reactive kinetics. The governing equations for the flow field, particle stress, kinetic equations, and particle orientation were coupled and were simultaneously solved using a finite element method based software, COMSOL. One of the main results was the changes in rheology of biomass suspension were not only due to the decrease in volume fraction of particles, but also due the types of fibres. The results from the simulation model agreed qualitatively with the experimental findings. This approach has enables us to obtain better predictive capabilities, hence increasing our understanding on the behaviour of biomass suspension.

Mechanistic Model for Ash Deposit Formation in Biomass Suspension Firing. Part 2: Model Verification by Use of Full-Scale Tests

A model for deposit formation in suspension firing of biomass has been developed. The model describes deposit build-up by diffusion and subsequent condensation of vapors, thermoforesis of aerosols, convective diffusion of small particles, impaction of large particles and reaction. The model describes particle sticking or rebound by a combination of the description of (visco)elsatic particles impacting a solid surface and particle capture by a viscous surface. The model is used to predict deposit formation rates measured during tests conducted with probes in full-scale suspension-fired biomass boilers. The rates predicted by the model was reasonably able to follow the rates observed in the tests, although with some variation, primarily as overestimations of the deposit formation rates. It is considered that the captive properties of the deposit surface are overestimated. Further examination of some physical parameters related to the description of surface capture are suggested. Based on these examinations ...

Mechanistic Model for Ash Deposit Formation in Biomass Suspension Firing. Part 1: Model Verification by Use of Entrained Flow Reactor Experiments

Two models for deposit formation in suspension firing of biomass have been developed. Both models describe deposit buildup by diffusion and subsequent condensation of vapors, thermophoresis of aerosols, convective diffusion of small particles, impaction of large particles, and reaction. The models differ in the description of the sticking probability of impacted particles: model #1 employs a reference viscosity in the description of the sticking probability, while model #2 combines impaction of viscoelastic particles on a solid surface with particle capture by a viscous surface. Both models were used to describe the deposit formation rates and deposit chemistry observed in a series of entrained flow reactor (EFR) experiments using straw and wood as fuels. It was found that model #1 was not able to describe the observed influence of temperature on the deposit buildup rates, predicting a much stronger influence of this parameter. Model #2 was able to provide a reasonable description of the influence of temp...

CFD-PBE Modelling and Simulation of Enzymatic Hydrolysis of Cellulose in a Stirred Tank

Renewable energy or biofuel from lignocellulosic biomass is an alternative way to replace the depleting fossil fuels. The production cost can be reduced by increasing the concentration of biomass particles. However, lignocellulosic biomass is a suspension of natural fibres and processing at high solid concentration is a challenging task because it will affect the mixing quality between the enzyme and cellulose particles and the generation of sugars. Thus, understanding the factors that affect the rheology of biomass suspension is crucial in order to maximize the production at a minimum cost. Our aim was to develop a solution strategy for the modelling and simulation of biomass suspension during enzymatic hydrolysis. The complete model was solved using the DAE-QMOM technique in a finite-element software package, COMSOL. Essentially, we made a clear connection between the microscopic and macroscopic properties of biomass slurries undergoing enzymatic hydrolysis. The results showed that the quality of mixing within a reactor is crucial in optimizing the hydrolysis product. The model improved the predictive capabilities, hence increasing our understanding on the behaviour of biomass suspension.

Biomass (yard waste) Suspensions as Alternative Daily Cover Material for Landfills

Biomass makes up approximately 16% of the landfills (this number can vary significantly depending upon the geographical location and time of the year). A majority of the biomass disposed in landfills is comprised of yard waste including grass and leaf clippings. This is becoming a problem as most landfills are running out of space and it is expensive to build new landfills. Twenty-four states have prohibited the disposal of yard waste in landfills with more states likely to follow suit. To conserve landfill space it is important to identify processes and methods for effective utilization and disposal of yard waste. It has been shown in this research that conformal coating of a biomass suspension can be utilized as an alternative daily cover (ADC) for the landfills. The biomass is ground into fine particles (d ≤ 2 mm) and suspended in a surfactant solution. This approach can reduce the cost of daily operations for the landfill and provide a solution to the problem of yard waste disposal.